Table of Content

12 April 2019, Volume 45 Issue 4

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REVIEW

Theoretical and technical models of quantitative regulation in food crop production system

ZHAO Ming,ZHOU Bao-Yuan,MA Wei,LI Cong-Feng,DING Zai-Song,SUN Xue-Fang

Acta Agronomica Sinica. 2019, 45(4):  485-498.  doi:10.3724/SP.J.1006.2019.83051

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Multi-objective collaborative development of crop production with high yield, high efficiency, and environmental friendliness is more important in China. Further improving theoretical models of crop system is a main way to adapt multi-objective coordinated development, and promote the sustainable development of crop production. In this paper, we reviewed current theoretical and technical regulation approaches for crop system. Meanwhile, according to the current crop production developing condition and previous researches, a new model “Three Collaboration Theory and Technology System” was established based on the overall composition of crop system, which can collaboratively optimize the relationship of “climate-crops”, “soil-crops”, and “population-individual” simultaneously. The application and perspective of such model were discussed.

CROP GENETICS & BREEDING·GERMPLASM RESOURCES·MOLECULAR GENETICS

Identification of indeterminate domain protein family genes associated with flowering time in maize

Yun-Fu LI,Jing-Xian WANG,Yan-Fang DU,Hua-Wen ZOU,Zu-Xin ZHANG

Acta Agronomica Sinica. 2019, 45(4):  499-507.  doi:10.3724/SP.J.1006.2019.83068

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Flowering time is one of the important factors affecting grain yield in maize (Zea mays L.). Indeterminate1 (ID1) is a known gene encoding indeterminate domain (IDD) protein which controls flowering time of maize. However, biological functions of the other IDD family genes are little known. In this study, we identified 37 IDD family genes, referred to as ZmIDDs by searching conserved IDD domains using bioinformatics strategy, and we then isolated these ZmIDDs by amplifying B73 genome using PCR. Diverse expression patterns of these ZmIDDs were revealed in eight tissues using B73 transcriptome data deposited in public database MaizeGDB (www.maizeGDB.org). In addition, we found that 35 ZmIDDs showed abundant genetic diversity with an average of 37.8 polymorphic loci per gene in 172 inbred lines, and seven ZmIDDs including ID1 were significantly associated with three flowering time-traits: days to tassel, days to anthesis and days to silking under multiple environments. We resequenced a 2 kb promoter region and 600 bp coding region of Zm00001d020683, and found 64 variants within 172 inbred lines. Candidate gene association analysis identified that two variants at promoter region were significantly associated with flowering time, and the haplotype composed of 3 bp and 2 bp insertion at the two associated loci showed an effect of shortening flowering time. The results provide a subset of flowering time-related candidate genes for further function assay and genetic improvement of flowering time in maize.

QTL mapping of salt and alkaline tolerance-related traits at the germination and seedling stage in maize (Zea mays L.) using three analytical methods

ZHANG Chun-Xiao,LI Shu-Fang,JIN Feng-Xue,LIU Wen-Ping,LI Wan-Jun,LIU Jie,LI Xiao-Hui

Acta Agronomica Sinica. 2019, 45(4):  508-521.  doi:10.3724/SP.J.1006.2019.83060

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The recombinant inbred line (RIL) F_2:5 population was derived from a cross between Zheng 58 tolerant to alkaline stress and Chang 7-2 sensitive to alkaline stress. By using the 3K chips, the high-density genetic map with 1407 SNP markers was constructed. The number of markers on 10 chromosomes ranged from 84 to 191, and the average physical distance between two markers was 0.81 cM. The germination percentage (GP), plant height (PH), fresh weight (FW), dry weight (DW), tissue water content (TWC), shoot Na ⁺ concentration (SNC), shoot K ⁺ concentration (SKC), shoot K ⁺/Na ⁺ ratio (NKR), salt tolerance rating (STR), or alkaline tolerance rating (ATR) were measured under 200 mmol L ^-1 NaCl solution of salt stress, 100 mmol L ^-1 Na₂CO₃ solution of alkaline stress and the normal water or full-strength Hoagland’s nutrient solutions irrigation as control conditions. The additive quantitative trait loci (QTLs) analysis was conducted by using the composite interval mapping (CIM) and the complete interval mapping method (ICIM), the additive and epistatic QTL × environment interaction effects were analyzed by using the mixed composite interval mapping method (MCIM). Compared with the normal condition, the alkaline stress decreased the tolerance more significantly than the salt stress. Maize was more sensitive to the alkaline stress. The harm of alkaline stress on maize was more serious. The SKC was comparable, but the SNC had great difference for alkaline and salt stresses indicating that the uptake and transport of Na ⁺ and K ⁺ were independent and salt and alkali were two different kinds of stresses. Under normal condition, salt stress and alkaline stress, 27, 28, and 40 additive QTLs were respectively detected by CIM, and 28, 13, and 17 additive QTLs were respectively detected by ICIM. By using MCIM, a total of 11 additive QTLs and 4 QTL × environment interaction QTLs for salt tolerance-related traits, as well as a total of 11 additive QTLs and 3 QTL × environment interaction QTLs for alkaline tolerance-related traits were detected. The QTLs qPH-9, qSTR-8, qNKR-6, qNKR-7 for salt tolerance and qPH-9, q-ATR-3 for alkaline tolerance were repeatedly detected by three mapping methods. After comparing the physical positions of these QTLs with those previously reported, we found qPH-9, qSTR-8, qNKR-6, and q-ATR-3 were located in the same or adjacent position, but qNKR-7 was newly reported. The present study provides a good basis for mapping major genes, mining candidate genes and developing practically functional markers applied in the improvement of salt and alkaline tolerance-related traits in maize.

Locating QTL controlling yield traits in overwintering cultivated rice

YAN Chao,ZHENG Jian,DUAN Wen-Jing,NAN Wen-Bin,QIN Xiao-Jian,ZHANG Han-Ma,LIANG Yong-Shu

Acta Agronomica Sinica. 2019, 45(4):  522-537.  doi:10.3724/SP.J.1006.2019.82045

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Overwintering cultivated rice is a type of special rice that can survive through cold-winter season, germinate in spring of the coming year, seed and be harvested. In this study, four genetic linkage maps contained 108, 116, 111, and 184 SSR markers were constructed using three half-sib F₂ populations from overwintering cultivated rice for the identification of QTLs affecting yield traits, respectively. Phenotypic values for yield traits were investigated for QTL mapping and other statistical analysis using Microsoft Excel 2003, GraphPadPrism 5.0, and QTL IciMapping 4.10. The phenotypic values for yield traits exhibited a continuously normal distribution and might be controlled by quantitative trait locus (QTL). A total of 37 QTLs affecting 15 yield traits and 26 epistatic QTL pairs with one or more interactions were detected in the three populations, explaining the wide phenotypic variance ranging from 2.32% to 36.31% and from 1.04% to 2.05% respectively. Among these QTLs, nine QTLs affecting two or more traits were detected on chromosomes 1, 3, 6, 8, 11, and 12 respectively. Thirteen QTLs affecting yield-related traits were detected by nested association mapping (NAM) mapping; four out of thirteen were overlapped with QTLs detected in single mapping population. The additive-dominance QTL affecting yield traits played an important role than that of epistatic QTL. Overall, this research lays a good foundation for the mining of yield-related genes from overwintering cultivated rice and their breeding innovation and utilization.

Effect of indica pedigree on yield and milling and appearance qualities in the offspring of indica/japonica cross

WANG Xu-Hong,LI Ming-Xiao,ZHANG Qun,JIN Feng,MA Xiu-Fang,JIANG Shu-Kun,XU Zheng-Jin,CHEN Wen-Fu

Acta Agronomica Sinica. 2019, 45(4):  538-545.  doi:10.3724/SP.J.1006.2019.82031

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Most of the rice cultivars in Northeast China has been released by crossing indica rice since the 1980s, especially in the new century. In order to clarify the influence of indica pedigree on the yield and quality of rice in northeastern China, 85 BILs derived from Sasanishiki (japonica)/Habataki (indica)//Sasanishiki///Sasanishiki were planted in Shenyang of Liaoning, Changchun of Jilin, and Harbin of Heilongjiang. The indica frequency (Fi) we defined is a ratio of indica type marker to all markers in order to analyses the relationships between yield traits and quality traits. The normal mature plant coefficients and Fi average values in Liaoning, Jilin and Heilongjiang gradually decreased from south to north, and the differences in biological yield, economic coefficient and economic yield were not significant (Biological yield and economic coefficient in Heilongjiang were missing). The spike number in Liaoning and Jilin were higher than that in Heilongjiang. The number of grains per panicle showed a trend in Heilongjiang>in Jilin>in Liaoning. The brown rice in Heilongjiang was significantly higher than that in Liaoning and the brown rice in Jilin was no significant difference compared with that in Liaoning and Heilongjiang. The milled rice rate and head rice rate were higher in Liaoning and Jilin than those in Heilongjiang. The chalkiness rice rate and chalkiness level showed trends in Liaoning>in Jilin>in Heilongjiang. The grain length, grain width and aspect ratio were not significantly different among the three areas. There were significantly negative correlations of Fi with 1000-grain weight, economic yield, economic coefficient, brown rice rate and grain width, and a significantly positive correlation with aspect ratio. The correlations between Fi and yield and its components were similar to those in the overall situation, but most parameters in Heilongjiang did not reach a significant level. There were a significantly negative correlation between Fi and grain width in Liaoning and Jilin, and only a significantly positive correlation between Fi and aspect ratio in Liaoning. Under the conditions of this experiment, controlling Fi at about 10% could be beneficial to complement each other of elite alleles from two subspecies, promote the japonica production into a higher level in Northeast China.

Improvement of oleic acid content in peanut (Arachis hypogaea L.) by marker assisted successive backcross and agronomic evaluation of derived lines

HUANG Bing-Yan,QI Fei-Yan,SUN Zi-Qi,MIAO Li-Juan,FANG Yuan-Jin,ZHENG Zheng,SHI Lei,ZHANG Zhong-Xin,LIU Hua,DONG Wen-Zhao,TANG Feng-Shou,ZHANG Xin-You

Acta Agronomica Sinica. 2019, 45(4):  546-555.  doi:10.3724/SP.J.1006.2019.84096

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High oleic acid content is a key quality trait in peanut varieties. Peanut and its products with high oleic acid content possess better quality stability and nutrition for benefiting peanut processing and human health. To date, the released high oleic acid varieties were few and most of which were derived by conventional breeding with narrow genetic background. In this study, Allele Specific-PCR-Mispairing (AS-PCR-MP) method and optimized KASP assay system were developed to facilitate successive marker-assisted backcross breeding strategy for high oleic acid content. We also applied Near Infra-Red technology and winter nursery in the five-year successive backcross and selfing. Four types of cultivars (Yuhua 15, Yuanza 9102, Yuhua 9327, and Yuhua 9326) were selected as recurrent parents for backcrossing. Twenty-four BC₄F₄ and BC₄F₅ stable lines with different genetic backgrounds and high oleic acid content were produced from four generations of successive backcrosses and four generations of BC₄ selfing. Similarities between BC₄ selfing progenies and recurrent parents were analyzed based on 13 agronomic traits. The recovery rate of genetic background for BC₄F₄ and BC₄F₅ was investigated by designing KASP assays with SNPs that were polymorphic between recurrent parents and non-recurrent parents. The proportion of genetic background of recurrent parents in BC₄F₅ was 79.49% to 92.31%. This study provides a new strategy for efficiently improving oleic acid content of peanuts with diverse genetic backgrounds. The near isogenic lines obtained in this study could be valuable genetic resources for further utilizations.

Physiological and biochemical analysis and gene mapping of a novel short radicle and albino mutant sra1 in rice

ZHANG Li-Sha,MI Sheng-Nan,WANG Ling,WEI Gang,ZHENG Yao-Jie,ZHOU Kai,SHANG Li-Na,ZHU Mei-Dan,WANG Nan

Acta Agronomica Sinica. 2019, 45(4):  556-567.  doi:10.3724/SP.J.1006.2019.82041

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The leaf color mutant is an ideal material for studying the process of photosynthesis and the pathways of chlorophyll synthesis and degradation. Studies on rice leaf color mutants are helpful to explain the gene network of chloroplast development and photosynthesis in higher plants. The mutant sra1, derived from the progeny of EMS-treated indica rice Xinong 1B. Leaves of sra1 were white in color from budding to the third leaf, and the radicle of sra1 was significantly shorter than that of wild type in the same stage. The observation of leaves in the same position showed that in Xinong 1B, the chloroplast of mesophyllous cells was abundant and the membrane system was fully developed, while in sra1, the vacuolarization of mesophyll cells was serious, the number of chloroplasts was significantly reduced or absent, and the granule thylakoids were loosely folded. The contents of chlorophyll a, chlorophyll b, and carotenoid in sra1 were close to zero, and the net photosynthetic rate was negative. Genetic analysis indicated that the short-root and albino phenotype was controlled by a single recessive nuclear gene, and SRA1 was localized between the long-arm InDel markers Z-20 and Z-42 of rice chromosome 3. The physical distance between the two InDel markers was about 657 kb. No genes related to chloroplast and root development have been reported in this interval, indicating that sra1 is a novel mutant. The sra1 is a novel mutant with albino and accompanying short roots, suggesting that SRA1 may be involved in regulating chloroplast and root development.

Excavation of main candidate genome regions in Suwan germplasm improvement process of maize

LI Xiu-Shi,WU Xun,WU Wen-Qiang,LIU Peng-Fei,GUO Xiang-Yang,WANG An-Gui,ZHU Yun-Fang,CHEN Ze-Hui

Acta Agronomica Sinica. 2019, 45(4):  568-577.  doi:10.3724/SP.J.1006.2019.83052

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Suwan germplasm with good resistance, strong adaptability and excellent grain quality has played an irreplaceable role in modern breeding, especially in the southern of China. It is important to clarify the genetic mechanism of Suwan germplasm. In this study, modified generations of Suwan 1 (Suwan 1 C₁₀) and its derived population (Suwan-Lancaster 1 C₀) were used to be genotyped by using MaizeSNP50 chips containing about 56,000 SNP markers. There was a smaller genome differences among different improved generations for Suwan 1 population, with only five different inherited fragments identified, among which four appeared only in the 11th improved generation (Suwan 1 C₁₁), one appeared only in the 15th improved generation (Suwan 1 C₁₅). For Suwan-Lancaster1 population, among 18 different genetic fragments eight were stably inherited in different improved generations. A total of 43 specific genetic segments of Lancaster germplasm were obtained, among them 35 were stably inherited in different improved generations. Genome-wide association studies (GWAS) showed that 16 QTNs significantly associated with kernel row number were located on chromosomes 2, 3, 5, 6, 7, 8, and 9, respectively, among them SYN25713 and SYN36577 were located in the Lancaster specific genetic fragment of the Suwan-Lancaster 1 population. A total of 13 QTNs related to ear length were located on chromosomes 1, 2, 5, 7, 8, and 9, respectively, among them PZE-105143697 was located in the Lancaster specific genetic fragment. These results provide an important theoretical basis for the subsequent genome-wide association study and molecular marker assisted selection.

TILLAGE & CULTIVATION·PHYSIOLOGY & BIOCHEMISTRY

Characteristics of medium-maturity conventional japonica rice with good taste and high yield in Jianghuai area

ZHU Ying,XU Dong,HU Lei,HUA Chen,CHEN Zhi-Feng,ZHANG Zhen-Zhen,ZHOU Nian-Bing,LIU Guo-Dong,ZHANG Hong-Cheng,WEI Hai-Yan

Acta Agronomica Sinica. 2019, 45(4):  578-588.  doi:10.3724/SP.J.1006.2019.82040

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A field experiment was conducted with 103 medium-maturity conventional japonica rice varieties (lines) including main varieties grown in Jianghuai area and released varieties in recent years with potential productivity, from which three types [good taste and high yield (GH), good taste and medium yield (GM), and medium taste and high yield (MH)] were selected to explore the characteristics of varieties with good taste and high yield in Jianghuai area. There was no significant difference in processing quality between GH type and MH type. Compared with MH type, GH type was 82.06%, 56.34%, and 93.28% higher in chalkiness rate, chalky area ratio and chalkiness, 14.21% and 39.78% lower in protein content and amylose content, 8.73% higher in gel consistency, and 282.11% and 37.88% lower in setback and consistence, respectively. The yield of GH type was 26.73% higher than that of GM type, due to large number of spikelets per panicle and high seed-setting rate. The panicles per unit land area was 22.26% lower, the number of spikelets per panicle and seed-setting rate were 42.12% and 6.18% higher, the ratio of productive tillers to total tillers was 4.2% higher in GH type than those in GM type. The LAI of GH type during heading and maturity periods was 5.47% and 16.94% higher and the decay rate of LAI was 7.25% lower than those of GM type. From heading to maturity, the dry matter accumulation and its ratio, the photosynthetic potential, the crop growth rate, the net assimilation rate and seed setting density were 24.07%, 15.50%, 17.59%, 13.96%, 3.67%, and 40.33% respectively higher in GH type than those in GM type. From above, GH type of medium-maturity conventional japonica rice has the following characteristics: the brown rice rate and the head milled rice rate reach the 1 grade of Chinese standard; the transparency is from grade 3 to grade 5; the protein content is around 8% and the amylose content is around 10%; the gel consistency is over 75 mm; the setback is below -300 cP and the consistence is below 600 cP; the number of panicles per unit land area is around 310×10 ⁴ ha ^-1, and the grains number per panicle is around 140. It can keep the dry matter accumulation and the leaf area index in optimum ranges before heading period, and remain the leaf area index, the dry matter accumulation and its ratios at high levels after heading period.

Characteristics of annual climate resource distribution and utilization in high-yielding winter wheat-summer maize double cropping system

ZHOU Bao-Yuan,MA Wei,SUN Xue-Fang,DING Zai-Song,LI Cong-Feng,ZHAO Ming

Acta Agronomica Sinica. 2019, 45(4):  589-600.  doi:10.3724/SP.J.1006.2019.81067

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To clarify the characteristics of the resource distribution and its use efficiency for wheat-maize cropping system with high yield potential of 20,000 kg ha ^-1 is essential for increasing annual yield and resource use efficiency in the Huang-Huai-Hai Plain. The relationship between high yield and distributions of radiation, accumulated temperature, and precipitation in seasons of winter wheat-summer maize cropping system was quantitatively analyzed by using the data of 45 field experiments from nine sites in Huang-Huai-Hai Plain from 2006 to 2010. The annual yield of winter wheat and summer maize in nine sites of the three provinces achieved more than 20,000 kg ha ^-1, with large differences among regions. Among the three provinces, the yield of wheat in Henan and Shandong and summer maize in Shandong was the highest, accounting for 16.9% and 21.5% higher than these in Hebei, respectively. The greater differences of yield among the three provinces mainly came from the distribution differences in radiation, accumulated temperature, and precipitation. The accumulated temperature and precipitation during wheat growth season in Henan and Shandong were higher than those in Hebei, when the accumulated temperature was from 1924.2°C to 2608°C, and rainfall was less than 201.1 mm; while the accumulated temperature, radiation, and precipitation during maize growth season in Shandong were higher than those in Henan and Hebei, when the radiation was 2168.5-2953.8 MJ m ^-2, the accumulated temperature was less than 2990.7°C, and rainfall was less than 591.3 mm. However, the relatively fixed resources distribution rate between winter wheat and summer maize was found among different experimental sites, the accumulated temperature distribution rate in wheat and maize season was 43% and 57%, respectively, the accumulated temperature ratio between two seasons was 0.7, which is the quantitative standard to dispose the reasonable resources distribution between growth seasons in winter wheat and summer maize. The results are of great significance for promoting the sustainable development of winter wheat and summer maize cropping system in the Huang-Huai-Hai Plain by using the quantitative indexes established in this study to optimize the distribution of resources between two seasons for traditional winter wheat-summer maize cropping system without any input.

TILLAGE & CULTIVATION·PHYSIOLOGY & BIOCHEMISTRY

Screening of germplasm tolerant to low phosphorus of seedling stage and response of root protective enzymes to low phosphorus in foxtail millet

YUAN Yi-Chuan, CHEN Xiao-Yu, LI Ming-Ming, LI Ping, JIA Ya-Tao, HAN Yuan-Huai, XING Guo-Fang

Acta Agronomica Sinica. 2019, 45(4):  601-612.  doi:10.3724/SP.J.1006.2019.82029

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The purpose of this paper was to explore the characteristics of low-phosphate tolerance in different genotypes of foxtail millet and establish an evaluation system for screening and breeding new cultivars with low-phosphate tolerance. Correlation analysis, principal component analysis, membership function and cluster analysis were carried out on 11 indicators of 160 core foxtail millet varieties, including plant heights, root lengths, fresh weights of aerial part and underground part, leaf lengths and widths, stem thicknesses, phosphorus contents of aerial part and underground part, dry weights of aerial part and underground part, to comprehensively evaluate indicators and characters related to low-phosphorous tolerance. Furthermore, a hydroponic experiment was conducted to cultivate selected varieties with low-phosphorus sensitivity and low-phosphorus tolerance under low phosphorus (LP) and normal phosphorus (NP) conditions, and superoxide dismutase (SOD) activity, peroxidase (POD) activity, and catalase (CAT) activity in roots were analyzed. There were nine varieties with low-phosphorus sensitivity, 66 and 70 varieties with medium low-phosphate tolerance and 15 varieties with low-phosphorus tolerance. The activities of SOD, POD, and CAT were increased under low phosphorus condition. It was concluded that the comprehensive index is more objective to evaluate the low-phosphorus tolerance of 160 foxtail millet variation at the seedling stage, and the root protective enzymes are important for the adaptability of foxtail millet to low-phosphorus stress.

TILLAGE & CULTIVATION·PHYSIOLOGY & BIOCHEMISTRY

Temperatures of promoting rapid leaf abscission of cotton in Xinjiang region

TIAN Jing-Shan,ZHANG Xu-Yi,ZHANG Li-Na,XU Shou-Zhen,QI Bing-Qin,SUI Long-Long,ZHANG Peng-Peng,YANG Yan-Long,ZHANG Wang-Feng,GOU Ling

Acta Agronomica Sinica. 2019, 45(4):  613-620.  doi:10.3724/SP.J.1006.2019.84068

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Machinical harvesters have increasing used in recent years, but excessive seed-cotton cleaning processes resulting from the higher foreign matter of mechanically harvested cotton cause unintended fiber damage. How to apply the defoliant to improve lint quality is a dominant cultural practice, because temperatures are unstable in the Xinjiang cotton belt with minimum dropping sharply in early autumn. The objective of this study was to analyze the relationship between temperatures and the rapid leaf abscission of cotton. The cotton leaf abscission rate was the highest, being from 55% to 79% at (7.0±1.0) days after defoliant application. And growing degree days (GDD) and maximum temperature were positively correlated with the cotton leaf abscission during (7.0±1.0) days after defoliant application. If obtaining more than 55% leaf abscission at (7.0±1.0) days after defoliant application, the maximum temperature and GDD should be more than 27.2°C and 7.0°C day, respectively. Therefore, the critical period promoting the good leaf abscission of cotton is during (7.0±1.0) days after defoliant application, and the dominant temperature factors influencing cotton leaf abscission are the maximum temperature and growing degree days.

Relationship of stem characteristics and lignin synthesis with lodging resistance of hulless barley

WANG Kai,ZHAO Xiao-Hong,YAO Xiao-Hua,YAO You-Hua,BAI Yi-Xiong,WU Kun-Lun

Acta Agronomica Sinica. 2019, 45(4):  621-627.  doi:10.3724/SP.J.1006.2019.81064

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Lodging is one of the main limiting factors affecting the quality and yield of hulless barley. It is of great significance to carry out the research on the lodging resistance mechanism and breeding lodging resistant varieties. The hulless barley varieties Kunlun 14, Kunlun 16, Zang 2972 were used as lodging resistant materials, and Menyuanlianglan, Beiqing 6, Hualonghongqingke as lodging materials, to measure the characteristics of stems, contents of cellulose and lignin in stems and activities of their related enzymes. Compared with the lodging varieties, the lodging resistant varieties had shorter stem, and stronger stem breaking-resistant strength. Four enzyme activities related to lignin synthesis were higher and more lignin was accumulated in the stems of lodging resistant varieties. The activities of tyrosine ammonia-lyase (TAL), phenylalanine ammonia-lyase (PAL), cinnamyl alcohol dehydrogenase (CAD), and 4-coumarate: CoA ligase (4CL) in the stems increased, which caused more lignin to accumulate in stems, increasing stem breaking-resistant strength and enhancing lodging resistance of hulless barley.

RESEARCH NOTES

Allohexaploid synthesis and its characteristic identification between cotton species Gossypium hirsutum and G. sturtianum

SHEN Zhuang-Zhuang,LI Yu-Ying,RONG Er-Hua,WU Yu-Xiang

Acta Agronomica Sinica. 2019, 45(4):  628-634.  doi:10.3724/SP.J.1006.2019.84086

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Gossypium hirsutum is an important cultivated cotton species and G. sturtianum is a wild cotton species with many excellent characteristics. In this study, we obtained fertile offsprings by interspecific distant hybridization and chromosome doubling between G. hirsutum and G. sturtianum. Through flow cytometry and meiosis observation of pollen mother cells, two heterohexaploid plants with complete chromosomes were selected. Further, the characteristic identification of their leaves, flowers and seeds was carried out, showing that the leaf shape of hexaploid was between their parents with increased leaf area, and the number of chloroplasts in guard cells obviously more than that of their parents and triploid. The flowers were significantly different between distant hybrids and their parents, and the pollen grain diameter of hexaploid was larger than that of parents and triploid. The fiber color of hexaploid was white, and the fiber length was shorter than that of G. hirsutum, and the traits of delayed seed gland development coming from G. sturtianum were expressed in the allohexaploid hybrids. These results of synthesized new fertile allohexaploid germplasms between G. hirsutum and G. sturtianum provide new valuable materials for the study of cotton genetics and breeding.

Effects of genotype and environment on wheat yield, quality, and nitrogen use efficiency

JIN Xin-Xin,YAO Yan-Rong,JIA Xiu-Ling,YAO Hai-Po,SHEN Hai-Ping,CUI Yong-Zeng,LI Qian

Acta Agronomica Sinica. 2019, 45(4):  635-644.  doi:10.3724/SP.J.1006.2019.81072

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An experiment was carried out at Guantao, Ningjin, and Gaocheng using five wheat varieties (thirteen strong gluten wheat varieties and two middle gluten wheat varieties) with four levels of nitrogen fertilizer application (0, 180, 240, and 300 kg ha ^-1). The average yield of different wheat varieties was 9289 to 10,088 kg ha ^-1; yield of strong gluten varieties was 9548 kg ha ^-1, which was 3.1% lower than that of middle gluten varieties. The yield in Gaocheng, Ningjin and Guantao was 9932, 9433, 9223 kg ha ^-1, respectively. The averaged grain protein content, wet gluten content, Zeleny sedimentation, dough stability time, extensibility energy and maximum resistance were 14.5%, 28.5%, 39.5 mL, 15.4 min, 87.5 cm ², and 428.8 BU, respectively. Gaoyou 5218, Gaoyou 5766, Jimai 738, Kenong 2009, Shiluan 02-1, Gaoyou 2018, and Jimai 738 had better quality. The wheat had better quality in Guantao and Ningjin than in Gaocheng. The nitrogen use efficiency decreased with nitrogen fertilizer increase. Under nitrogen fertilizer application of 180 kg ha ^-1, nitrogen agronomic efficiency, recovery efficiency and internal efficiency were the highest, with 4.3 kg kg ^-1, 26.2% and 16.6 kg kg ^-1, respectively. Gaocheng was suitable for growing Jimai 738, Jimai 867, and Shiluan 02-1. Ningjin was suitable for growing Shiluan 02-1, Kenong 2009, and Jimai 738. Guantao was suitable for growing Gaoyou 5766, Gaoyou 2018, and Shiluan 02-1. Taking grain yield, quality and nitrogen use efficiency into account, 180 kg ha ^-1 is the optimum nitrogen application under the similar condition of this study.