Table of Content

12 July 2009, Volume 35 Issue 7

Previous Issue    Next Issue

CROP GENETICS & BREEDING·GERMPLASM RESOURCES·MOLECULAR GENETICS

Identification and Molecular Mapping of Xa32(t),a Novel Resistance Gene for Bacterial Blight(Xanthomonas oryzae pv.oryzae)in Rice

ZHENG Chong-Ke,WANG Chun-Lian,YU Yuan-Jie,LIANG Yun-Tao,ZHAO Kai-Jun

Acta Agron Sin. 2009, 35(7):  1173-1180.  doi:10.3724/SP.J.1006.2009.01173

Abstract ( 2368 )   PDF (471KB) ( 1561 )   Save

References | Related Articles | Metrics

The rice bacterial blight (BB), caused by Xanthmonas oryzae pv. oryzae (Xoo),is the most devastating bacterial disease of rice worldwide. Use of resistant varieties has been thought the most economical and environment-friendly approach to control BB of rice. Since the rapid changes of the pathogenicity of the pathogen (Xoo), new BB resistance genes are always needed for rice breeding. We, here, report the identification and molecular mapping of a new BB resistance gene from Oryzae ustraliensis. Based on the resistance spectrum analysis, we identified a new rice germplasm, C4064, for bacterial blight (BB) resistance. Leaf-cutting innoculation assays showed that C4064 was resistant to Xoo strains P1 (PXO61), P4 (PXO71), P5 (PXO112), P6 (PXO99), P7 (PXO145), P8 (PXO280),P9 (PXO339), and KX085, but susceptible to P2 (PXO86) and P3 (PXO79). Comparison of resistance spectrum with that of all the known BB resistance genes and genetic analysis revealed that the rice germplasm C4064harbored a new BB-resistance gene, designated as Xa32(t). To molecularly map Xa32(t) gene,Bulked Segregant Analysis (BSA) was adopted to survey SSR and EST molecular markers. Out of 299 markers tested, six markers RM27256, RM27274, RM2064, ZCK24, RM6293, and RM5926 on rice chromosome 11 displayed polymorphism between the S-pool and R-pool. By analyzing the F₂ and F₃ populations, the gene Xa32 (t) was mapped on the long arm of rice chromosome 11. Linkage analysis revealed that molecular markers RM27256, RM27274, RM2064, and ZCK24 were located between Xa32 (t) and the centromere of the chromosome, with genetic distances of 2.1, 1.0, 1.0, and 0.5 cM to Xa32 (t), respectively; while RM6293 and RM5926 were located onthe othersideof Xa32(t), with genetic distances of 1.5 and 2.6 cM to Xa32 (t), respectively. Thus, the new BB-resistance gene Xa32(t) was mapped within a length of 2.0 cM on the long arm of rice chromosome 11. The results of this study will be useful in fine mapping of Xa32(t) and marker-assisted breeding for BB resistant rice varieties.

Cloning and Analysis of a Salt Stress Related Gene TaMYB32 in Wheat

ZHANG Li-Chao,ZHAO Guang-Yao,JIA Ji-Zeng,KONG Xiu-Ying*

Acta Agron Sin. 2009, 35(7):  1181-1187.  doi:10.3724/SP.J.1006.2009.01181

Abstract ( 2458 )   PDF (888KB) ( 2023 )   Save

References | Related Articles | Metrics

Transcriptional factors play an important role in plant adapt ability to abiotic stress at molecular level. MYB transcriptional factor family is a multifunctional gene family that have been found some of them take part in response to plant abiotic stress.In the large-scale sequencing of the wheat full length cDNAs cloned in our laboratory and functional analysising of transcriptional factors, a salt stress related gene was screened out and named TaMYB32. TaMYB32 is 1 250 bp in full length with a 732 bp ORF, encoding a R2R3-MYB transcriptional factor with 244 amino acids. The sequences of TaMYB32 were cloned from the diploid ancestors of Triticum urartu UR206, Aegilops speltoides Y2006 and Aegilops tauschii Y2282 and hexaploid wheat of Chinese Spring and Chadianhong using the primers designed based on the cDNA sequence of TaMYB32. Sequence analysis indicated that two types of sequences existed in the diploid ancestors and four in hexaploid wheat. One of the sequences was the same in the diploid and hexaploid wheats which implied that TaMYB32 was very conservative during the evolution of wheat. After comparing the genomic sequences with their cDNA sequences of TaMYB32, we found that it was a non-intron gene. TaMYB32 was mapped onto wheat homoeologous group 6 using electronic mapping strategy; there were two copies in each genome of hexaploid wheat, which was consistent with the sequencing results. Homologous analysis found thatTaMYB32 had a similarity with R2R3-MYB proteins from rice and maize as high as 72.4% and 73.7%, respectively. Tissue specific analysis indicated that TaMYB32 expressed in root, stem, leaf, pistil and anther. Semi-quantitative and real-time RT-PCR revealed that the expression of TaMYB32 was induced by salt stress.

Expression Profile of Landrace Hongyoumai Infected by Blumeria graminis f.sp.tritici Using Gene Microarray

WANG Jun-Mei,LIU Hong-Yan,XU Hong-Ming,WANG Fei,GAO Su-Xia,

Acta Agron Sin. 2009, 35(7):  1188-1193.  doi:10.3724/SP.J.1006.2009.01188

Abstract ( 2695 )   PDF (201KB) ( 2169 )   Save

References | Related Articles | Metrics

Wheat landrace Hongyoumai carries one dominant resistance gene for powdery mildew (Blumeria graminis), tentatively designated Pmhym. To further elucidate molecular mechanism of the resistance to powdery mildew in Hongyoumai, a resistant pool was constructed with four homogenous resistant lines from the F₃ generation of Yumai 13/Hongyoumai. The wheat seedlings were inoculated with single spore isolates of B. graminis f. sp. tritici, and at 0 and 24 h after inoculation the gene expression profile was analyzed using Affymetrix wheat microarray. There were approximately 5 282 expressed genes (with Log ratio ≥ 2 or ≤ 0.5) among total 61 127 genes set in the microarray plate, including 2 553 up-regulated and 2729 down-regulated genes or expressed sequence tags (ESTs). In the up-regulated ESTs whose functions have been known, 39.81% were disease/defense genes. In the down-regulated ESTs, energy genes and disease/defense genes accounted for 26.71% and 19.65%, respectively. A total of 81 ESTs were up-regulated more than eight times, in which most were related to disease resistance, such as pathogenesis-related protein, defense genes, genes producing or eliminating reactive oxygen species, and genes involved in signal transduction. Quantitative RT-PCR (qRT-PCR) was carried out with 13 probe sets up-regulated and down-regulated more than eight times which validated a good reproducibility of microarray analysis.

Molecular Identification and Expression Analysis of  GhCYP51G1 Gene，a Homologue of Obtusifoliol-14α-demethylase Gene， from Upland Cotton（Gossypium hirsutum L.）

TAN Kun-Ling,HU Ming-Yu,LI Xian-Bi，QIN Shan,LI De-Mou,LUO Xiao-Ying, et al.

Acta Agron Sin. 2009, 35(7):  1194-1201.  doi:10.3724/SP.J.1006.2009.01194

Abstract ( 2011 )   PDF (732KB) ( 1785 )   Save

References | Related Articles | Metrics

Besides as a precursor of BL biosynthesis, more and more evidences support the hypothesis that phytosterols possess a BL-independent signaling pathway. Furthermore, the obtusifoliol is regarded as a signal molecule in sterol signaling. To understand the effects of phytosterols on the development of cotton (Gossypium hirsutum L.) fibers and the molecular basic of sterol signaling in cotton fiber growth, we cloned a gene encoding a homologue of obtusifoliol 14α-demethylase from developing fibers of upland cotton cv. Xuzhou 142 through screening cotton fiber EST (Express Sequence Tag) database and contigging the candidate ESTs. The full length of GhCYP51G1 (GenBank accession No. EU727154) was 1 710 bp, including a 160 bp 5'-untranslated region (UTR), a 1461 bp open reading frame (ORF), and an 89 bp 3'-UTR. The GhCYP51G1 encoded a polypeptide of 486 amino acid residues with a predicted molecular mass of 55.2 kD. The deduced amino acid sequences had high homology with the members of CYP51 family in plant kingdom. Moreover, many typical conserved regions were characterized as the obtusifoliol 14α-demethylase, such as substrate recognition sites (SRS) and heme-binding region presented in the deduced protein. Quantitative real-time RT-PCR analysis revealed that the higher expression levels of GhCYP51G1 gene were detected in 8-DPA, 12-DPA, 18-DPA fibers, and 12-DPA ovules. These results indicate that GhCYP15G1 gene plays an important role in fiber elongation. Furthermore, Auxin significantly down regulates the expression level of GhCYP51G1 in cotton fiber growth. This suggested that phytosterols play a role in the interaction of plant hormones, especially brassinosteroids and auxin.

Expression of ARC1 in Vitro and Test of Interaction between ARC1 and SRK from Brassica oleracea L. in Signal Transduction Pathway of Self-Incompatibility

NIU Yi,WANG Zhi-Min,GAO Qi-Guo,SONG Ming,WANG Xiao-Jia,ZHU Li-Quan

Acta Agron Sin. 2009, 35(7):  1202-1208.  doi:10.3724/SP.J.1006.2009.01202

Abstract ( 1961 )   PDF (386KB) ( 1419 )   Save

References | Related Articles | Metrics

Self-incompatibility (SI) is a widespread mechanism in flowering plants that prevents inbreeding and promotes outcrossing. Self-pollen recognition relies on the products of genes located at the S (self-incompatibility) locus. Significant progress has been made in understanding molecular interactions allowing stigmatic cells to recognize and reject self-pollen in Brassica during the past decades. Thus, the male and female determinants responsible for the self-incompatibility (SI) response have been identified. The structural features of these molecules strongly suggest that SI response is triggered by a ligand-receptor interaction. ARC1 is anArm Repeat Containing and also a downstream gene of SRK. ARC1 interacts with SRK probably in signal transduction pathway of self-incompatibility. In this study, with an aim to testify the interaction, the coding sequences of ARC1 were amplified from stigma mRNA of Brassica oleracea L., and inserted into the expression vector pET43.1a to construct the recombinant plasma pET43.1a-ARC1, transformed E. coli(BL21) and detected expression of the recombinant protein via SDS-PAGE. Using Co-Immunoprecipitation theory and characteristic of 6×His Tag combined with Ni+ in pET43.1a-ARC1, a new method was put forward for testing the interaction between proteins. Through the method the interaction between ARC1 and SRKwas analyzed, showing that ARC1 and SRK could act with each other to combine and form a complex. This research provides a theoretical and technical bases for further analyzing the mechanism of interaction between ARC1 and SRK, for probing into interaction between ARC1 and downstream targets.

Strategy of Sampling for Pre-Core Collection of Sugarcane Hybrid

LIU Xin-Long,CAI Qing,MA Li,WU Cai-Wen,LU Xin,YING Xiong-Mei

Acta Agron Sin. 2009, 35(7):  1209-1216.  doi:10.3724/SP.J.1006.2009.01209

Abstract ( 2249 )   PDF (211KB) ( 1770 )   Save

References | Related Articles | Metrics

Sugarcane is a major economic crop in the world and sugarcane hybrids provides an important gene pool for sugarcane. The National Nursery of Sugarcane Germplasm Resources (NNSGR) in China has maintained a large collection of sugarcane hybrids from over ten provinces of China and twenty countries around the world. In this study, 1 202 sugarcane hybrids were selected as materials, 26 sampling procedures were used, which consisted of 4 grouping principles (cluster grouping, grouping based on original regions, grouping based on planting regions and not grouping), 4 sampling proportions within group (simple proportion, logarithmic proportion, square root proportion and genetic proportion), 2 individual selection methods within group (random selection and cluster selection) on the basis of 23 quantitative and qualitative traits. At the same time, 10 grads for sampling percentage (5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, and 50%) from total resources were analyzed to decide the best one of them. The sampling strategies and the pre-core collection were validated and evaluated with five effective parameters including indices of genetic diversity, variance of phenotypic value, variance of phenotypic frequency, coefficient of variation and ratio of phenotypic traits retained. The result indicated that the cluster sampling was better than the random sampling; cluster grouping was the best grouping principle; square root proportion was the best sampling proportion within group in clustering sampling, genetic proportion was the best in random sampling. Finally, an optimal pre-core collection was set up based on cluster grouping, logarithmic proportion, and cluster sampling according to 10% sampling percentage by analyzing 26 sampling strategies and 10 sampling ratio. The pre-core collection contained 136 accessions, which accounted for 11.31% of total resources and its genetic diversity was better than that of total resources. They included 120 accessions sampled by program and 16 accessions chosen by directional selection, which included the elite ones and some with the rare phenotypic traits.

Associated Analysis between Temporal and Spatial Expression of Fiber Development Genes and Fiber Quality

JU Ming, WANG Hai-Tang, WANG Li-Ke, LI Fei-Fei, WU Shen-Jie, ZHU Hua-Yu, et al.

Acta Agronomica Sinica. 2009, 35(7):  1217-1228.  doi:10.3724/SP.J.1006.2009.01217

Abstract ( 2623 )   PDF (911KB) ( 1875 )   Save

References | Related Articles | Metrics

Ten genes expressed preferentially in fiber development period reported previously and 14 cotton cultivars (strains) with distinctly different fiber quality were selected in this paper. To test the relative expression values of the genes in six different fiber developmental stages, 0 day post anthesis (DPA), 5 DPA, 10 DPA, 15 DPA, 20 DPA, 23 DPA, by real-time quantitative RT-PCR (qRT-PCR), and the data of fiber qualities from 14 cotton varieties (strains). The expression profile showed that GhExp1, GhCIPK1,GhSus1, GhSusA1 and GhPL genes were expressed preferentially during fiber elongation; GhACT1、GhRacA and GhRacB genes all had high expression level in earlier stage of fiber elongation and the thickening period of secondary cell wall. Two cellulose synthase genes (GhCelA1 and GhCelA3) were expressed predominantly during late stage of fiber elongation and the thickening period of secondary cell wall. For most genes, the expression value in low expression level period had significant correlation with fiber quality, while no significant correlation was detected in preferential expression stage of these genes with an exception of GhRacA gene. The expression level of GhExp1 in 20DPA fiber of 14 cotton varieties (strains) had a significant negative correlation with fiber strength and uniformity and a significant positive correlation with fiber elongation percentage; the expression level of GhPL gene in 23DPA had a significant negative correlation with fiber length; the expression level of GhRacA gene in 5DPA and 23DPA both had a high significant positive correlation with fiber elongation percentage; the expression level of GhRacB gene in 10DPA had a significant negative correlation with fiber length and uniformity; the expression level of GhCelA1 gene in 5DPA had a significant positive correlation with fiber length and a significant negative correlation with micronaire value; the expression level of GhCelA1 gene in 10DPA had a significant negative correlation with fiber length, a significant positive correlation with micronaire value, and a high significant correlation with fiber elongation percentage; the correlation between the expression levels of GhCIPK1, GhACT1, GhSus1, GhSusA1and GhCelA3 gene and fiber quality indexes had not been detected.

Characterization and Genetic Analysis of Grain Filling Rate of Ludao and Restorer Line C-Bao in Japonica Rice(Oryza sativa L.)

ZHANG Qi-Wu,JIANG Jian-Hua,YAO Jin,HONG De-Lin

Acta Agron Sin. 2009, 35(7):  1229-1235.  doi:10.3724/SP.J.1006.2009.01229

Abstract ( 2177 )   PDF (422KB) ( 1355 )   Save

References | Related Articles | Metrics

Plants of hybrid japonica rice with large panicles usually possess fewer productive panicles per plant and have poor plumpness for a number of fertilized grains. “Ludao” is a kind of primitive japonica rice of O. sativa L., which expressed strong tillering ability and short grain filling duration. In order to overcome the barrier of poor plumpness of japonica hybrid rice with large panicles, grain filling rate of 6 filling stages (1–7 d, 8–14 d, 15–21 d, 22–28 d, 29–35 d, and 36–42 d after flowering) were investigated using 6 generations (P₁, P₂, F₁, F_2, B₁ and B₂) in the reciprocal crosses derived from “Ludao” and C Bao, a restorer line of japonica rice. And genetic analysis for average grain filling rate over whole filling duration was conducted by using the methods of components of means and the mixed major gene plus polygene inheritance models. Research results were as follows: (1) No cytoplasmic effect was found for average grain filling rate based on reciprocal analysis. (2) The largest filling rate appeared in the second stage (8–14 d after flowing) in P₁, P₂ and their F₁. (3) The whole filling duration of Ludao was 28 days, 14 days shorter than that of C Bao, and average filling rate in Ludao was fast by 50% as compared with that in C Bao. (4) The inheritance of average grain filling rate fitted additive-dominance- epistasis model based on the analysis of components of means. The average filling rate was controlled by two major genes with additive-dominance-epistatic effects plus polygene with additive-dominance-epistatic effects based on the mixed major gene plus polygene inheritance models, and was mainly governed by major genes.

Development and Identification of InDel Marker Based on rhg1 Gene for Resistance to Soybean Cyst Nematode(Heterodera glycines Ichinohe)

NAN Hai-Yang,LI Ying-Hui,CHANG Ru-Zhen,QIU Li-Juan

Acta Agron Sin. 2009, 35(7):  1236-1243.  doi:10.3724/SP.J.1006.2009.01236

Abstract ( 2402 )   PDF (365KB) ( 2034 )   Save

References | Related Articles | Metrics

Soybean cyst nematode (Heterodera glycaines, SCN) is one of the most important pests of soybean in the world. New molecular markers developed from resistance genes can provide marker resources for MAS (marker-assisted selection) breeding. Among four InDel loci detectedby comparing thesequences of candidate rhg1 conferringSCN resistance, three multiple-bases InDel loci were used to develop markers. A total of 11 alleles were detected in 33 cultivated soybean germplasm using three InDel markers developed. There were 5 alleles at rhg1-I1 locus, 2 and 4 at rhg1-I2 and rhg1-I4 respectively. Allelic variations at three InDel markers were assayed in the genotypes and discovered that rhg1-I4 marker was related to SCN resistance, which could distinguish 88.2% of resistant germplasm and 100% of the susceptible germplasm. Alleles of 288 and 294 bp presented in the SCN-resistant germplasm, and alleles 269 and 272 bp presented in the SCN-susceptible germplasm. In addition, rhg1-I4 could be used in MAS for the progenies of cross between typical southern US cultivar Lee crossed and the important resistant source PI88788. Combing with Satt309 which displayed the identical allele on these genotypes, rhg1-I4 would be higher effective in identifying germplasm with rhg1 conferring resistance in the MAS breeding.

Characterization,Molecular Cloning and Phylogenetic Analysis of Three y-Type High Molecular Weight Glutenin subunit genes from Aegilops tauschii of the Middle Reaches of Yellow River

SU Ya-Rui,ZHANG Da-Le,ZHANG Ming,LI Suo-Ping*

Acta Agron Sin. 2009, 35(7):  1244-1252.  doi:10.3724/SP.J.1006.2009.01244

Abstract ( 2075 )   PDF (448KB) ( 1172 )   Save

References | Related Articles | Metrics

Aegilops tauschii (2n = 2x = 14, DD), an ancestral specie of Tiriticum aestivum (2n = 6x = 42, AABBDD), possesses extensive allelic variation in high molecular weight glutenin subunits (HMW-GS). The elite genetic recourses are of great value in quality improvement of T. aestivum. Ae. tauschii is distributed in the middle reaches of Yellow River, and its HMW-GS genes have not been investigated in large scales. To detect HMW-GS genes in Ae. tauschii resources in this area and to understand its structure and function by sequencing, 161 Ae. tauschii accessions collected in July 2006 were used in this study with Yumai 49 as a control. Through sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) technique, three y-type subunits were observed, named as Dy10.5^t, Dy10.4^t , and Dy10.5^*t. Genes of the three subunits were amplified, cloned and sequenced by allele-specific PCR. The results revealed that the deduced amino acid sequence had typical characters of HMW-GS and a general resemblance to each other, but Dy10.4t had a repeated amino acid motif deletion to Dy10.5^t, and Dy10.5^*t had an amino acid substitution sites in signal peptide domain to Dy10.5^t (L-F). From multiple sequence alignment and phylogenetic analysis of storage protein gene family, it is concluded that the subunits Dy10.5^t, Dy10.4^t, and Dy10.5^*t of Ae. tauschii are similar to the Glu-1 locus found in wheat and related species, and are new members of y-type HWM glutenin family.

Codl Tolerance of Transplastomic Tobacco Lines Carrying Insect Antifreeze Protein

WANG Yan,MA Ji,HUANG Wei,QIU Li-Ming,YE Feng,ZHANG Fu-Chun

Acta Agron Sin. 2009, 35(7):  1253-1360.  doi:10.3724/SP.J.1006.2009.01253

Abstract ( 2074 )   PDF (465KB) ( 1952 )   Save

References | Related Articles | Metrics

The antifreeze protein gene MpAFP149 from desert insect Microdera punctipennis dzungarica was inserted into soybean chloroplast vector pJY01 to construct recombinant chloroplast vector pJY01-MpAFP149 by designing special primers. The plasmid was then transformed into tobacco by gene gun. Four transplastomic tobacco lines were obtained by spectinomycin screening. PCR and PCR-Southern analysis showed that the MpAFP149 gene was successfully integrated into the tobacco chloroplast genome, but the transgenicplants exhibited low homoplasmy. The result of RT-PCR also validated that MpAFP149 gene was transcribed at mRNA level. The antifreeze effect of transplastomic tobacco with insect antifreeze protein gene in its chloroplasts was evaluated by measuring the relative conductivity and comparing the phenotypes of different plants after cold treatment. Wild-type tobacco, transplastomic tobacco and T₁ generation of transgenic tobacco containing pCAMBIA1302-MpAFP149 in its nuclei were subjected to –1℃ for different days (0, 1, 2, and 3 d). The results showed that transgenic plants with insect antifreeze protein gene in chloroplasts or in nuclei performed better phenotype after cold treatment at –1℃ for three days and recovering at room temperature for five days than wild-type tobacco. After three days, the electrolyte leakage reached 73.7% for wild-type tobacco, 39.2% for chloroplast transgenic plants and 38.2% for nuclei transformed T₁ generation tobacco. There was no cold tolerance difference between nuclei transgenic tobacco and heterogeneous tansplastomic tobacco in our research.

Segregation of Chromosomes and Traits of Hybrid Generations Derived from Cross between Triticum aestivum and Amphidiploid of Aegilops ventricosa X Aegilops cylindrica

WANG Yu-Hai,WANG Li-Ming,BAO Yin-Guang,CUI Fa,HAO Yuan-Feng,et al.

Acta Agron Sin. 2009, 35(7):  1261-1267.  doi:10.3724/SP.J.1006.2009.01261

Abstract ( 1990 )   PDF (361KB) ( 1496 )   Save

References | Related Articles | Metrics

SDAU18 is an amphidiploid derived from the cross between Aegilops ventricosa and Ae. cylindrical, which carries excellent traits from the both parents. Because of the good crossability with common wheat (Triticum aestivum L.), it also acts as a bridge material to transfer objective genes from Ae. ventricosa and Ae. cylindrical to improved wheat cultivarsthrough hybridization. To disclose the chromosome segregation of hybrid progenies derived from common wheat ´ SDAU18 cross, we used a common wheat cultivar Yannong 15 as female parent and recurrent parent to develop hybrid generations F₁, F₂, F₃, F₄, F₅, BC₁F₁, BC₂F₁, BC₃F₁, and BC₁F₂. The mitosis in root tip cells and meiosis in pollen mother cells were observed. Agronomic traits, such as plant height, spike length, spikelet number per spike, grain number per spike, and seed-setting rate were also investigated in BC₁F₁, BC₂F₁, and BC₃F₁ generations. In higher generations of selfing and backcross, the chromosome number gradually decreased and eventually tended to 42, which was the same as common wheat. Backcrossing was able to fasten the process than selfing. In the F₅ and BC₃F₁ generations, plants with 42 chromosomes were accounted for 93.9% and 92.0%, respectively. Chromosome configuration in PMCs MI was simpler in backcross generations than in selfing ones. Compared with the BC₁F₁ and BC₂F₁ generations, BC₃F₁ showed less diversity in chromosome configuration, indicating that excessive backcross resulted in less chromosomes recombination between SDAU18 and common wheat. Two or three rounds of backcross were feasible. With the increasing generation of selfing and backcross, fertility of the hybrid was improved till the stable status in F₃ and BC₂F₁ generations. In various generations, variant plants with excellent traits were found, such as dwarf plant, huge spike, large grain, high resistance or immunity to powdery mildew and stripe rust, and good appearance of grain. In particular, the F₃ and BC₁F₁ generations had the most variation types.

Genotype Analysis and QTL Mapping for Tolerance to Low Temperature in Germination by Introgression Lines in Soybean

JIANG Hong-Wei,LI Can-Dong,LIU Chun-Yan,ZHANG Wen-Bo,QIU Peng-Cheng,et al.

Acta Agron Sin. 2009, 35(7):  1268-1273.  doi:10.3724/SP.J.1006.2009.01268

Abstract ( 2119 )   PDF (547KB) ( 1759 )   Save

References | Related Articles | Metrics

Northeast of China is the main soybean production area. Low temperature is one of the main factors to reduce soybean yield and to limit soybean production spreading to north regions. Shortening the growth stage is considered as one way of solving the problem, but the effective way is to breed cultivars with low temperature to tolerance. The identification of low-temperature tolerance germplasm is the basis for soybean breeding. A set of backcross introgression lines were constructed with Hongfeng 11 as recurrent parent and Clark as donor parent, 46 individuals were screened out, which were more tolerant than recurrent parent Hongfeng 11 under low temperature condition. Fifty individuals from BC₁F₄ were used as control (random population). Fourteen QTLs on ten linkage groups for tolerance to low temperature in germination were detected with genotype analysis by chi-test and one-way ANOVA. Twelve excessive-introgression alleles from donor parent with positive effect were acquired by chi-square and 5 alleles by ANOVA. Satt237, SOYPRP1, and Satt540 were detected by the two methods, so the three loci should be the main effect QTL and more believable. Introgression lines were used for mapping QTL related with tolerance to low temperature in germination, and the molecular mechanism could be studied in the further research on the platform established in this study for molecular assisted breeding.

Mapping of Wheat Stripe Rust Resistance Gene YrZH84 with RGAP Markers and Its Application

YIN Gui-Hong,WANG Jian-Wu,WEN Wei-E,HE Zhong-Hu,LI Zai-Feng,et al.

Acta Agron Sin. 2009, 35(7):  1274-1281.  doi:10.3724/SP.J.1006.2009.01274

Abstract ( 2447 )   PDF (505KB) ( 1830 )   Save

References | Related Articles | Metrics

Zhou 8425B, with an effective stripe rust resistance gene YrZH84, is a hall-mark parent line of wheat (Triticum aestivum L.) in the Yellow-Huai rivers wheat growing region. An F₂ population derived from the cross Zhou 8425B/Chinese Spring and their parents were used forpolymorphism analysis employing the resistance gene-analog polymorphism (RGAP) markers and bulked segregant analysis (BSA) based on marker genotypes and phenotypes selection. An RGAP marker Xrga-1 was identified, which was tightly linked to the stripe rust resistance gene YrZH84, with a genetic distance of 0.8 cM. The fragment amplified by Xrga-1 was 343 bp. BLAST analysis indicated that the rga-1 showed 93% of identical nucleotide sequences to barley stem rust resistance gene Rpg1, and 92% to barley powdery mildew resistance gene Mla homology family. Fifty-eight cultivars from Yellow-Huai rivers wheat growing region were genotyped by the RGAP marker Xrga-1. From the information of genotypes, pedigrees and resistance responses, the cultivars Zhoumai 11, Zhoumai 20, Zhoumai 22, Aikang 58, 04 Zhong 36, Yuanyu 3, 05 Zhong 37, Wuankang 18, and Yuzhan 10 were identified to have the resistance gene YrZH84. These cultivars were the derivatives of Zhou 8425B. These results will greatly benefit the marker-assisted selection in wheat and cloning of the resistance gene YrZH84.

TILLAGE & CULTIVATION·PHYSIOLOGY & BIOCHEMISTRY

Effects of Nitrogen Application Rate and Growth-Development Type on Milling Quality in Japonica Rice

MA Qun,ZHANG Hong-Cheng,DAI Qi-Gen,WEI Hai-Yan,HUO Zhong-Yang，et al.

Acta Agron Sin. 2009, 35(7):  1282-1289.  doi:10.3724/SP.J.1006.2009.01282

Abstract ( 2149 )   PDF (253KB) ( 1506 )   Save

References | Related Articles | Metrics

Nitrogen is the most important and largest input required in rice production although over use of N causes so many environment problems. The milling quality is one of the important aspects of rice quality. The effect of nitrogen application rate on milling quality is varied in different rice varieties, especially in different types. In this research, the field experiment for milling quality was carried out with 57 Japonica rice varieties including five growth-development types, planting in the region of Yangtze River, under four nitrogen levels (zero, low, medium and high) to investigate the difference of rice types under four nitrogen levels. Genotypic difference of head rice rate in response to nitrogen levels was discussed and their types were also classified. The main results were as follows: (1) As the increase of nitrogen application, the brown rice rate, milled rice rate and head rice rate of all the rice varieties were improved although the range of improvement decreased gradually. And there was no significant difference in head rice rate between medium and high nitrogen level. (2) In general, the longer of rice growth duration, the better of rice milling quality. According to this research, the milling quality of late japonica rice was better than that of medium japonica rice and the milling quality of late mature rice variety was superior to that of early mature rice varieties. The head rice rate of late japonica rice was higher than that of medium japonica rice by 19.07% on an average. (3) The response of head rice rate to nitrogen varied significantly. According to the variation coefficient of head rice rate under different nitrogen levels, rice varieties could be classified into three types including insensitive type, intermediate type and sensitive type. The varieties with high and stable head rice rate under all nitrogen levels and with high head rice rate at only high nitrogen application rate were recommended to be used in production.

Simulation Model of Cottonseed Protein and  Oil Formation

LI Wen-Feng,ZHOU Zhi-Guo,XU Nai-Yin,CHEN Bing-Lin,MENG Ya-Li*

Acta Agron Sin. 2009, 35(7):  1290-1298.  doi:10.3724/SP.J.1006.2009.01290

Abstract ( 1996 )   PDF (505KB) ( 1233 )   Save

References | Related Articles | Metrics

The simulation of cotton (Gossypium hirsutum L.) seed growth is an area of great uncertainty, especially in the process of cottonseed quality formation. To simulate the formation of cottonseed protein and oil under different environmental conditions, we developed a simple process-based model driven by the inputs of cultivar parameters, weather information, and crop management variable (precisely N supply). A set of field experiments were conducted with Kemian 1 and NuCOTN 33B in the lower reaches of Yangtze River Valley (Nanjing, Huai’an) and the Yellow River Valley (Xuzhou, Anyang) in 2005. Two sowing dates and three N rates were set in the trials. According to the data collected in Nanjing, the response functions of cottonseed protein and oil accumulation to weather conditions (temperature, solar radiation), crop management (variable N supply) and boll positions were all developed and involved in the model. The subtending leaf N concentration of cotton boll obtained from a semi-empirical equation was made as a direct indicator of the N nutrition affecting cottonseed quality formation. The model was based on the hypothesis that nitrogen accumulation and oil synthesis in cottonseed are mainly sink-determined, and was integrated with the cotton boll maturation period model and cottonseed biomass accumulation model. The parameters in the model were calibrated using the field data obtained in Nanjing. The model was tested using the field data obtained in Huaian, Xuzhou and Anyang. The root mean square error (RMSE) of the simulated and measured cottonseed protein contents was 2.05% for Kemian 1 and 2.33% for NuCOTN 33B. The RMSE of the simulated and measured cottonseed oil content was 2.45% for Kemian 1 and 2.95% for NuCOTN 33B. Driven by the inputs of data including weather conditions (daily maximum, minimum and average temperatures and daily solar radiation), management variable (precisely N supply), the present model accurately predicted cottonseed protein content and oil content under diverse environmental conditions. This model is a necessary component of cotton growth model, and provides a good platform for further study on modeling cottonseed protein and oil yield.

Relationship of Nicotine and Total Nitrogen Contents with Neutral Aroma Components in Flue-Cured Tobacco in Central Area of Henan Province

SHI Hong-Zhi,DI Hui-Hui,ZHAO Xiao-Dan,LIU Guo-Shun,MA Yong-Jian,et al

Acta Agron Sin. 2009, 35(7):  1299-1305.  doi:10.3724/SP.J.1006.2009.01299

Abstract ( 2150 )   PDF (311KB) ( 1577 )   Save

References | Related Articles | Metrics

The flavor quality of tobacco is highly correlated with nicotine content, while the relationship between aroma components and nicotine content is unknown. The aroma constituents come from different precursors and contribute differently to aroma styles. A total of 27 Flue-cured tobacco samples were collected from full aroma tobacco growing areas to investigate the relationship of nicotine and total nitrogen contents with neutral volatile aroma component contents by GC/MS. Results showed that there existed significantly positive quadratic correlation relationship between nicotine, total nitrogen and carotenoid catabolite contents, with the maximum carotenoid catabolites contents at the nicotine content of 3.82%. In the range of nicotine contents from 1.28% to 3.92%, the contents of megastigmatrieonel 2, megastigmatrieonel 4, farnesyl acetone, dihydroactinidiolide, and geranyl acetone kept going up with increasing nicotine content. Significant positive quadratic correlation relationship also existed between nicotine, total nitrogen and solanone, the cembratriendiol catabolite, while the solanone content was highest at the nicotine content of 2.62% and the total nitrogen content of 2.77%, then decreased significantly. Only a very few Mallard reaction compounds had significant correlations with nicotine and total nitrogen. Aromatic amino acid catabolites, neophytadiene, and total amount of volatile aroma compounds had significant quadratic correlations with nicotine and total nitrogen contents, and at the nicotine content of 2.89% and total nitrogen content of 3.05%, the total amount of volatile aroma compounds reached maximum value.

Contents of Grain Protein Components and Their Relationships to Processing Quality in Wheat

SHI Yu,ZHANG Yong-Li,YU Zhen-Wen

Acta Agron Sin. 2009, 35(7):  1306-1312.  doi:10.3724/SP.J.1006.2009.01306

Abstract ( 2504 )   PDF (282KB) ( 2200 )   Save

References | Related Articles | Metrics

Qualitative and quantitative analyses of glutenin and gliadin contents are important for quality improvement in wheat (Triticum aestivum L.). Although several studies have focused on the relationship between grain processing quality and protein components, there are no consistent conclusions, especially the effects of glutenin and gliadin components on processing quality need to be further studied. In this study, the contents of albumin + globulin, gliadin, HMW-GS, and LMW-GS of 12 wheat cultivars were measured using reversed-phase high-performance liquid chromatography (RP-HPLC). According to glutenin content, gluten protein content, and dough stability time, the 12 cultivars were classified into three groups, namely high-glutenin-content (I), medium -glutenin-content (II), and low-glutenin-content III) groups. Each group consisted of four cultivars. Content of each protein component varied with cultivars, and the content of gluten protein was the main factor to determine total protein content. The content of total protein was positively correlated (P < 0.05) with content of each protein component, and the contents of HMW-GS, LMW-GS, and glutenin had significantly positive correlations with dough development time, stability time, and sedimentation volume. Positive correlations were also observed between HMW/LMW and the development time and stability time of dough. However, the ratio of Gli/HMW-GS was negatively correlated with development time and stability time, and the ratio of Gli/Glu was negatively correlated with dough stability time. High contents of glutenin, HMW-GS, and LMW-GS as well as, large HMW/LMW ratio and small Gli/Glu ratio in wheat grains are favorable for high processing quality in strong-gluten wheat.

Morphogenesis and Physiological Basis in Wheat Cultivars with Different Levels of Cold-Resistance during Cold Acclimation and Freezing Period

WANG Xiao-Nan,FU Lian-Shuang,LI Zhuo-Fu,SUN Yan-Li,WANG Yu-Bo et al.

Acta Agron Sin. 2009, 35(7):  1313-1319.  doi:10.3724/SP.J.1006.2009.01313

Abstract ( 2308 )   PDF (476KB) ( 1569 )   Save

References | Related Articles | Metrics

“Dongnong dongmai 1” is the released cultivar of winter wheat (Triticum aestivum L.) in Heilongjiang province in China. However, the physiological metabolism in the over-wintering process of the cultivar is unclear. In this study, the plant morphological characters were investigated and several physiological parameters were measured with comparisons of three winter wheat cultivars, Dongnong Dongmai 1 (cold tolerant), Dongnong 705 (semitolerant to coldness), and Jimai 22 (cold susceptible), the objective was to understand the physiological adaptation to low temperature of Dongnong Dongmai 1. The numbers of leaf, tiller, and tiller leaf as well as water content in plant were investigated from 3 Oct. to 8 Nov. at a 5 d interval. Leaf, sheath, and tiller nod were sampled from 22 Oct. to 22 Dec. at a 10 d interval. The numbers of tiller and tiller leaf were significantly higher in Dongnong Dongmai 1 than in other cultivars before frozen period. Under cold stress, water content decreased in all parts of cultivars. Dongnong Dongmai 1 had the largest reduction of water content in leaf, but the water content in tiller nod declined slower and maintained the highest level among the three cultivars. In contrast, Jimai 22 had relatively higher water content in leaf and sharp reduction in tiller nod. The electric conductivity measurement indicated that leaves died at 30, 20, and 0 d after the frozen day in Dongnong Dongmai 1, Dongnong 705, and Jimai 22, respectively. The total soluble sugar content in leaves and leaf sheathes was the highest in Dongnong Dongmai 1, and the lowest in Jimai 22. Similarly, during frozen period, the content of total soluble sugar in tiller nod was the highest in Dongnong Dongmai 1 and the lowest in Jimai 22. Superoxide dismutase (SOD) in leaf was inactivated at 20 d after the frozen day in Dongnong 705 and Jimai 22, but maintained the certain activity even at 40 d after the frozen day in Dongnong Dongmai 1. Moreover, the activities of SOD in all parts of Jimai 22 were lower than those of other cultivars. During frozen period the activities of peroxidase (POD) were higher in sheath and tiller nod in Dongnong Dongmai 1, it was higher in tiller nod and lower in leaf sheath in Dongnong 705, and cignificantly lower both in sheath and tiller nod in Jimai 22.The results suggest that high resistance to coldness in Dongdong Dongmai 1 is probably related to the translocation of total soluble sugar from leaf to sheath and tiller nod. Low water content in plant and relative high activities of SOD and POD in sheath and tiller nod are also contributed to the cold-resistance of Dongnong Dongmai 1.

Monitoring Grain Protein Accumulation Dynamics with Canopy Reflectance Spectra in Wheat

FENG Wei,ZHU Yan,CAO Wei-Xing,ZHU Yun-Ji,GUO Tian-Cai

Acta Agron Sin. 2009, 35(7):  1320-1327.  doi:10.3724/SP.J.1006.2009.01320

Abstract ( 2031 )   PDF (350KB) ( 1429 )   Save

References | Related Articles | Metrics

Grain protein is an important index indicating wheat quality status, and nondestructive and quick assessments of grain protein accumulationdynamics is necessary for cultural regulation and quality classification in wheat (Triticum aestivum L.) production. The objectives of this study were to determine the relationships between plant nitrogen nutrition status, grain protein accumulation, and canopy reflectance spectra in winter wheat, therefore, to derive regression equations for monitoring grain protein accumulation with canopy hyper-spectral remote sensing. Three types of cultivars, i.e., high protein content (Xuzhou 26 and Yumai 34), medium protein content (Yangmai 10, Yangmai 12, and Huaimai 20), and low protein content (Ningmai 9) were used in three field experiments under different nitrogen levels in the growing seasons of 2003–2006. Time-course measurements were taken on canopy hyperspectral reflectance, plant weight, nitrogen content and grain protein accumulation (GPA) during the experimental periods. The results showed that the cumulative value of canopy nitrogen nutrition index (CNNI) from anthesis to specific day were highly correlated with grain protein accumulation at corresponding day across grain filling with the best predictor of plant N accumulation (PNA). According to the regression analyses between vegetation indices and canopy nitrogen nutrition index,several key spectral parameters could accurately estimate the changes in plant N status across different growth stages, nitrogen levels, and growing seasons with the same spectral parameters for each wheat cultivar. According to the technical route of key spectral parameters-canopy N nutrition index-grain protein accumulation, estimating models on grain protein accumulation were constructed on the basis of canopy hyper-spectral parameters by linking the above two models with canopy N nutrition index as intersection in wheat. Tests with other independent dataset showed that the key spectral index SDr/SDb on the basis of the technical route of SDr/SDb-PNA-GNA could be used to predict grain protein accumulation from 7d after anthesis to maturity, with the predictive precision (R²) of 0.954 and the relative error (RE) of 13.1%, respectively. It can be concluded that dynamic change of grain protein accumulation in wheat could be monitored directly with key vegetation spectral index.

GGE Biplot Analysis of Effects of Planting Density on Growth and Yield Components of High Oil Peanut

CHEN Si-Long,LI Yu-Rong,CHENG Zeng-Shu,LIU Ji-Sheng

Acta Agron Sin. 2009, 35(7):  1328-1335.  doi:10.3724/SP.J.1006.2009.01328

Abstract ( 2495 )   PDF (289KB) ( 1762 )   Save

References | Related Articles | Metrics

Peanut planting density directly affects peanut yield and yield components, it is an effective way to adopt an optimal growing system for improving yield level. The paper presents an optimum density of peanut cultivation and a new method of data analysis. Five treatments (densities at 7.5×10⁴, 105×10⁴, 150×10⁴, 195×10⁴, and 240×10⁴ holes per hectare) were designed with peanut cultivar Jihua 4. We investigated the agronomic traits, economic traits, yield components and pod yield in peanut, analyzed the differences between growing densities and every trait determined by SAS (Statistical Analysis System) and GGE (Genotype main effects plus Genotype×Environment interaction model). The results showed that there were inconsistent performances between traits and densities. The number of flowers per plant in the whole growth period, the number of pods per plant, pod yield per plant and pod yield per hectare were more sensitive to peanut planting density, but the main stem height, lateral branches length, shelling percentage, oil yield per hectare and protein yield per hectare were more stable. The number of flowers per plant in the whole growth period, the number of pods per plant, 100-pod weight and pod yield per plant decreased significantly with the increase of planting density, but pod yield per hectare increased. Pod yield produced by plants with the highest planting density were slightly greater than those with the lower planting density, while with planting density increasing, the increasing degree of pod yield per hectare decreased. Although the total pod yield increased with density, the higher yield achieved at the higher density did not give a higher economic profit which also affected by seed cost for planting. The result showed that the optimal planting density of Jihua 4 was from 105.0×10⁴ to 150×10⁴ holes per hectare based on maximal economic profit. GGEbiplot is a new and more realistic and effective method to analyze growth and yield components of high oil peanut cultivar.

Regulation Effects of Exogenous Hormones on Growth and Photosynthesis and Yield of Rapeseed（Brassica napus L.）after Frozen

Acta Agron Sin. 2009, 35(7):  1336-1343.  doi:10.3724/SP.J.1006.2009.01336

Abstract ( 2334 )   PDF (447KB) ( 2073 )   Save

References | Related Articles | Metrics

Different contents of exogenous hormones were applied on rapeseed at the initial blossoming stage. The net photosynthetic rate (P_n) and yield were investigated. In January 2008, a heavy snow and low temperature for a period destroyed crops including winter rape. In this experiments exogenous hormones ABA and BR with optimal contents were applied on the rapeseed (Brassica napus L.) plants after the frozen from the worst weather. The gas exchange parameters and chlorophyll fluorescence characteristics of leaves as well as the regularity of pod size changes and yield components were determined. The results were as follows: ABA (76×10^-6 mol L^-1)and BR(1×10^-6 mol L^-1) could delay the decreasing of net photosynthetic rate (P_n) in short petiole leaves. The P_n, stomatal conductance (G_s), intercellular CO₂ concentration (C_i), transpiration rate (T_r) and photosynthetic saturated light intensity (LSP) were increased after exogenous hormones treatment. ABA and BR treatments also caused a significant increase in the maximus photchemical efficiency of photosystem II (F_v/F_m), the quantum yield of electron transport (Φ_PSII), the photochemical quenching co-efficient (q_P), Chl content and soluble protein content. These changes were accompanied by the decline in both minimal fluorescence (F_o) and non-photochemical quenching co-efficient (NPQ). The pod surface areas per pod were increased. The number of the first branches per plant and seeds per pod and 1000-seed weight were raised, resulting in improvement of yield after BR treatment. As to the plants after ABA treatment, the high yield was mainly attributed to the increasing of seeds per pod and 1000-seed weight. In conclusion, ABA (76×10^-6 mol L^-1) and BR (1×10^-6 mol L^-1) treatments are effective on promoting the growth and relieving the negative effects of frozen on rapeseed.

Effects of Phosphorus Deficiency on Growth and Nitrogen Fixation of Soybean after Nodule Formation

MIAO Shu-Jie,QIAO Yun-Fa,HAN Xiao-Zeng*,WANG Shu-Qi,LI Hai-Bo

Acta Agron Sin. 2009, 35(7):  1344-1349.  doi:10.3724/SP.J.1006.2009.01344

Abstract ( 2257 )   PDF (411KB) ( 1822 )   Save

References | Related Articles | Metrics

Phosphorus had a key role in soybean growth, however, it is very different to separate the role in soybean growth from that in nodule function. The research was conducted to elucidate the effects of phosphorus deficiency on growth and nitrogen fixation after nodule formation in soybean. Soybean seedlings were cultivated in nutrient solution culture with normal phosphorus concentration (30 µmol L^-1), which was shifted to 0 and 4 µmol L^-1 after nodule formation resulting in phosphorus deficienct for soybean plants.The results showed that phosphorus deficiency negatively influenced soybean plant growth at the ninth day of phosphorus deficiency treatment and nitrogen fixation at the beginning of the treatnent. The nodule number increased by 11.8%, 15.4%, and 20.0%, respectively in 0, 4, and 30 µmol L^-1 phosphorus treatments at the ninth of treatment (DOT) compared with that at the third DOT. Leghemoglobin concentration per gram of plant and per nodule biomass increased with phosphorus concentration increase. These suggested that phosphorus deficiency affected significantly nodule development and nitrogen fixation when soybean plants formed sufficient nodule.

RESEARCH ACTIVITIES

Effect of Fertilization on Yield of Forage Grass，Nutrient Uptake and Soil Properties under Sudangrass and Ryegrass Rotation Regime

LI Wen-Xi,LU Jian-Wei,LU Jun-Ming,LI Xiao-Kun,DAI Zhing-Gang,YANG Juan

Acta Agron Sin. 2009, 35(7):  1350-1356.  doi:10.3724/SP.J.1006.2009.01350

Abstract ( 2149 )   PDF (256KB) ( 1173 )   Save

References | Related Articles | Metrics

Sudangrass and ryegrass rotation is a new type of growth system in Jianghan Plain, which had developed very fast in recent years. So it is highly essential to propose an optimum nutrient management practice for increasing forage grass yield, improving soil fertilization and assuring sustainable development in this new system. Effect of fertilization on yield of forage grass, nutrient uptake and nutrition in soil under Sudangrass and ryegrass rotation regime was studied for two years through the field experiments in Honghu City of Jianghan Plain. The results showed that the application of nitrogen (N), phosphorus (P) and potassium (K) combination obviously improved fresh yield of Sudangrass and ryegrass, with a total forage yield of 162.7 t ha^-1 in 2005–2006, which was 312.9%, 26.9%, 17.9% higher than that of PK, NK, NP treatments, respectively. The total forage yield was 114.9 t ha^-1 in 2006–2007, and 338.5%, 20.3%, 17.2% higher than that of PK, NK, NP treatments, respectively. Fertilization affected nutrient content of forage grass, and N fertilizer increased N content of grass, and K fertilizer increased K content of grass. NPK combination also promoted nutrient uptake of forage grass, with the higher nutrient uptake than other treatments. The total N, P, K uptake of forage grass was 500 kg ha^-1, 91 kg ha^-1and 997 kg ha^-1 in 2005–2006, and 312 kg ha^-1, 56 kg ha^-1, 402 kg ha^-1 in 2006–2007, respectively. In this rotation, the surplus of N and P₂O₅ in NPK treatment was the least, compared with that in NP, NK and PK treatments. However, K₂O surplus in NPK treatment was the negative. In Sudangrass and ryegrass rotation, organic matter and total nitrogen in soil in all treatments, available phosphorus in soil in NPK, NP and PK treatments and available potassium in soil in NPK, NK and PK treatments increased with crop rotation times. But available phosphorus in soil in NK treatment and available potassium in soil in NP treatment slightly degraded, respectively.

Characteristics of Roots Traits in Conventional Indica Rice Cultivars with Large-Panicle

DONG Gui-Chun,LI Jin-Qian,TIAN Hao,YU Xiao-Feng,ZHANG Biao,ZHANG Chuan-Shen,etal

Acta Agron Sin. 2009, 35(7):  1357-1363.  doi:10.3724/SP.J.1006.2009.01357

Abstract ( 2061 )   PDF (271KB) ( 1322 )   Save

References | Related Articles | Metrics

Eighty-eight and one hundred and twenty two conventional indica rice cultivars were solution-cultured in 2001 and 2002, respectively. Dry matter weight (including root system, culm and sheath, leaves, panicle), root traits, root physiological activity, yield and its components were measured. The tested rice cultivars were classified into six types (i.e. A, B, C, D, E, and F, A was the lowest, and F was the highest) based on their panicle weight level by the MinSSw method, to study their differences of root traits, root physiological activity. Difference of panicle weight of the cultivars used in this study was very large (the ratio of the maximal panicle weight to the minimum panicle weight in 2001 and 2002 were 493% and 764%, respectively), the average of panicle weight was 0.99, 1.56, 2.00, 2.54, 3.16, and 4.08 grams per panicle in 2001, and 0.82, 1.38, 1.80, 2.38, 3.04, and 4.29 grams per paniclein 2002, respectively. Root dry weight per plant, total length of adventitious roots per plant, and total root absorption area per plant in large-panicle type cultivars higher than those in small-panicle type cultivars. Number of adventitious roots per panicle, root dry weight per panicle, length of adventitious roots per panicle, total root absorption area per panicle, root active absorption area per panicle, and root activity per panicle in large-panicle type cultivars were higher than those in small-panicle type cultivars. Polynomial regression analysis showed that panicle weight was significantly influenced by length of adventitious roots per panicle, root dry weight per panicle, ratio of shoot to root at heading stage, root activity per panicle, and the determinant coefficient ranged from 0.620 to 0.639. Larger panicle weight could be reached by increasing length of adventitious roots per panicle, root dry weight per panicle, ratio of shoot to root at heading stage, root activity per panicle.

Effect of tilling Depth on Growth,Nutrient Uptake,Yield and Quality of Flue-Cured Tobacco Plant

XU Tian-Yang,ZHAO Zheng-Xiong,LI Zhong-Huan,CHEN Rong-Ping,XU Long,et al.

Acta Agron Sin. 2009, 35(7):  1364-1368.  doi:10.3724/SP.J.1006.2009.01364

Abstract ( 2109 )   PDF (243KB) ( 1431 )   Save

References | Related Articles | Metrics

Deeper tillage has been commonly thought having positive effect on plant growth, but what depth for tillage is better is not clearly in tobacco production. A field experiment was conducted to investigate the effect of tilling depth (20, 30, and 40 cm, respectively) on the growth, root distribution, dry matter accumulation, nutrient uptake, yield and quality of flue–cured tobacco plant in Shilin county, Yunnan. The results showed that tobacco plant growth was significantly affected by the tilling depth from topping to harvesting except the early stage. The number and dry weight of roots decreased with increasing tilling depth at the 0–10 cm soil layer, but increased at the 10–20 cm and 20–30 cm soil layers, and more roots were found for the treatment with tilling depth at 40 cm. Leaf area index, maximum leaf area, dry matter accumulation and uptake of nitrogen, phosphorus and potassium increased in the plant with deepening tilling depth. The highest yield and economic value of flue-cured tobacco leaves were obtained at 40 cm of tilling depth. Moreover, the 30 cm of tilling depth was also better for higher yield and higher quality of leaf. It suggested that 30 to 40 cm was the optimum tilling depth for flue-cured tobacco.

Effects of Chemical Ripeners on photosynthetic Characteristics of Pods and Rapeseed Quality and Yield

ZHOU Ke-Jin,GUAN Chun-Yun,XIAO Wen-Na,TAN Tai-Long

Acta Agron Sin. 2009, 35(7):  1369-1373.  doi:10.3724/SP.J.1006.2009.01369

Abstract ( 2290 )   PDF (330KB) ( 1952 )   Save

References | Related Articles | Metrics

We investigated the effects of chemical ripeners Diguat and Roundup on photosynthetic rate, gas exchange parameters and chlorophyll content in pods, 1000-grain weight and yield and oil content through gas exchange measuring technology during the latest stage of pod growth. The ripener Diquat, with a good effect on accelerating pods ripening, damaged pod peel chlorophyll seriously, decreasedphotosynthetic rate, and light-energy utilization efficiency rapidly, so that the 1000-grain weight, yield and quality decreased largely, which sensitively depends on the Diquat content. In comparison, the ripener Roundup, with a slow effect on pods ripening, had a less injury on pod growth and a higher photosynthetic rate, so that the yield and quality of grains were higher. Our investigations disclosed a close relationship of grain yield and oil content with P_nand chlorophyll content, proving the importance of utilization efficiency of light energy in the latest stage of pods ripening on the grain yield and oil accumulation. In production, we recommend an appropriate ripener recipe of 0.1% Diguat or 0.8% Roundup for accelerating pods ripening with a less loss of the grain yield.

Polymorphism Analysis of Seedling Storage Proteins in Foxtail Millet（Setaria italic L.Beauv.）with A-PAGE

YANG Yan-Bing,ZHANG Hua-Wen,QIN Ling,WANG Hai-Lian,GUAN Yan-An*,DUAN Nai-Bin

Acta Agron Sin. 2009, 35(7):  1374-1378.  doi:10.3724/SP.J.1006.2009.01374

Abstract ( 2039 )   PDF (353KB) ( 2092 )   Save

References | Related Articles | Metrics

The polymorphism of water-soluble protein, salt-soluble protein, acid-soluble protein and prolamin was analyzed by A-PAGE in 24 foxtail millet varieties from different ecological zones. The results revealed that the banding patterns of the water-soluble protein in different millet varieties were similar to those of the acid-soluble protein. There existed over twenty bands of the salt-soluble protein in each millet variety, and only four varieties contained polymorphic bands, showing that bands of the water-soluble protein, the salt-soluble protein and the acid-soluble protein obtained by A-PAGE are not available to use in millet varieties identification. There existed a certain degree of heterogeneity in millet prolamin bands. Seven to ten prolamin bands appeared in tested varieties, five of which were the common ones, two to five of which were polymorphic, so prolamin patterns of millet varieties can be used in variety identification and evaluation. The results showed that there was less variance for proteins in tested millet varieties from different ecological zones compared with other major cereal crops like wheat and corn, which implies that only a limited heterogeneity in the genetic background of millet varieties. Therefore, it is very important to enrich the genetic basis of millet genetic stocks to develop elite varieties.