The spikelet number per panicle is a key factor that constitutes the grain yield in rice. Modern high-yielding rice varieties mostly show high spikelet number per panicle. Increasing the spikelet number per panicle and promoting the formation of large panicles are important ways to improve rice yield. This paper reviewed the relationship between the formation of spikelet number per panicle and young panicle development in rice. Combined with the author’s related research, the mechanisms underlying genetic regulation in rice panicle size, the effects of nutritional status and nitrogen fertilizer management, water, temperature, light, and endogenous hormones on the formation of spikelet number per panicle in rice were reviewed. We put forward the future research focus on strengthening the formation of large panicles in rice from the aspects of root morphophysiology and young panicle development, water and nitrogen management, temperature and light conditions, and the physiological and molecular mechanisms of interaction between plant hormones regulating spikelet degeneration. The purpose of this study was to provide a basis for the selection and cultivation of high-yielding rice varieties with large panicles.

The sheathed panicle phenomenon is a disadvantageous trait in agricultural production, which is mainly due to the abnormal elongation of the uppermost internode, resulting in the panicle closed by flag leaf sheath. Although some mutants of sheathed panicle have been identified and reported in rice, the underling molecular mechanism of uppermost internode shortening is still poorly understood. OsPSS1/SUI1 is a phosphatidylserine synthase gene and the mutation of OsPSS1 leads to a severe shortening of the uppermost internode of mutant sui1-4. We discovered and identified a new allelic mutant sui1-5 of SUI1 and the degree of the uppermost internode shortening in sui1-5 was significantly reduced. Sequence analysis revealed a single nucleotide substitution of G to T at the seventh exon of SUI1 in sui1-5, resulting in an amino acid change from glycine to valine. To study the function of OsPSS1, we detected a protein GH9A3 interacting with SUI1 through a yeast screening library, which was verified by yeast two-hybrid, luciferase complementarity (LCI), and bimolecular fluorescence complementarity (BiFC). GH9A3 was a member of GH9 gene family, encoding an endo-β-1,4-glucanase which was speculated to be a key enzyme in cell wall cellulose synthesis. At seedling stage, the relative expression level of SUI1 was not synchronized with that of interaction protein-coding gene GH9A3, and the relative expression level of GH9A3 was up-regulated in sui1-5. But at heading and jointing stage, the relative expression level of SUI1 and GH9A3 decreased synchronously, and the relative expression level of other cellulose synthase CESAs family genes decreased obviously in sui1-5. These results lay a foundation for further study of the function of OsPSS1.

Four yield traits and five fiber quality traits of their 298 varieties (lines) and their 884 F₂ crosses of upland cotton were analyzed for their additive and dominance effects by a genetic model with additive, dominance, and their interaction effects with the environment in two successive years in Alar, South Xinjiang. To explore the potential of the breeding and utilization value of varieties, all varieties were clustered using cluster analysis of the R software package based on the additive and dominance effects. The results indicated that under the high-density planting mode of “low plant growth (plant height: 0.8-1.0 m), high density (225,000-300,000 plant hm^-2), early ripe and film cover” in southern Xinjiang province, the additive effects of 298 parents were divided into 12 groups. The average additive effects of yield and fiber quality traits of 23 varieties (lines) in the sixth group were in a good level. It was easy to obtain offspring with both yield (except lint percentage) and fiber quality traits through crossing between these varieties (lines). The eighth group had a better average additive effect on fiber quality traits, while the fourth group had a higher average additive effect on yield traits. The progeny with complementary yield and fiber quality traits could be obtained by crossing these two kinds of varieties. The dominance effects of 298 parents were divided into nine groups. The eighth group included eight varieties (lines) and their yield traits and fiber quality traits (except micronaire) were all at a better average level in dominance effect, indicating that could be used as parents for hybrid utilization of both yield traits and fiber quality traits. The average dominance effect of yield traits was higher in the eighth category, and the average value of dominance effect of fiber quality traits in the third group was higher.

Tassel size affects the nutrient allocation synthesized by photosynthesis in maize, which in turn affects ears development and the yield components, such as kernel rows, kernel number per row, seeding rate, and kernels weight per one hundred. In this study, haploids were induced using the F_2:3 families, which were constructed from the elite inbred lines Zheng 58 and B73. Genotypes were obtained by 48K liquid phase hybridization capture probes technique, and phenotypes were evaluated in multi-environment trails. QTL mapping was performed using the inclusive composite interval mapping (ICIM) method. The RRBLUP model was used for genomic selection to explore the effects of training population size and the number of SNP markers on prediction accuracy. The results showed that the heritabilities of tassel length, tassel primary branch number, tassel secondary branch number, and tassel branch number were 0.82, 0.88, 0.84, and 0.88, respectively. Two QTL, located in bins 1.03 and 4.09, were detected for tassel length with phenotypic variation explained (PVE) of 6.02% and 11.10%, respectively. Two QTL, located in bins 1.05 and 4.05, were detected for tassel primary branch with PVE of 9.17% and 11.75%, respectively. Two QTL, located in bins 2.03 and 3.06, were detected for the tassel secondary branch with PVE of 5.51% and 5.65%, respectively. Two QTLs, located in bins 1.04 and 4.05, were detected for the tassel branch number with PVE of 9.37% and 10.83%, respectively. Tassel primary branch number and tassel branch number identified a same QTL located in bin 4.05 with multiple effects. The prediction accuracy of five-fold cross-validation for genomic selection was 0.36, 0.41, 0.28, and 0.37, respectively. When the training population reached 60% of the total population and the marker density reached 500, a high prediction accuracy could be obtained.

In this study, the advanced backcross population of semi-fertility plant 10 (sfp10) mutation constructed by rice pollen semi-fertile mutant lsm and indica rice cultivar 93-11 (wild-type, WT) was used as the research subjects. Compared to the WT, there were no significant differences in plant height, leaf length, leaf width, tiller number, pollen number and other agronomic traits, but pollen fertility reduced significantly. Pollen microscopy and scanning electron microscopy (SEM) at the late stage of pollen development showed that starch accumulation in some pollen of sfp10 decreased observably, eventually led to pollen abortion. Physiological indexes related pollen development revealed that the contents of proline and starch in pollen of the sfp10 mutant decreased significantly. Sucrose accumulation generally increased in the upstream tissues (source leaf, sink leaf, and stem) of panicle, but sucrose content decreased significantly in panicle, indicating that transport from sucrose to panicle was affected. Genetic analysis indicated that the sfp10 phenotype was controlled by a pair of recessive nuclear genes. Gene preliminary mapping located the mutant site into a 398 kb interval between RM25389 and RM25404 on rice chromosome 10, which contained 3 genes related to sucrose transport and 1 gene related to starch synthesis. This study laid a foundation for further research on fine mapping, gene function, and regulation mechanism of pollen semi-fertility regulation genes.

Suitable plant height (PH) and ear height (EH) can improve the efficiency of nutrient utilization and lodging resistance, which is of great significance for stable and high yield in maize. In this study, an association panel including 854 maize inbred lines used to analyze the PH, EH, and the ratio of EH to PH (EH/PH) in four environments, and genome-wide association study (GWAS) was then conducted using 2795 single nucleotide polymorphism (SNP) markers distributed uniformly throughout maize genome. A total of 81 SNP loci (P < 0.0001) were identified by using FarmCPU model, among which 35 SNPs were significantly associated with PH, with phenotypic variation explained (PVE) ranging from 0.020% to 6.225%; 31 SNPs were significantly associated with ear height, and PVE was from 0.026% to 3.060%; 24 SNPs were significantly associated with EH/PH, and the PVE ranged from 0.032% to 6.636%. 15 stable SNPs that were repeatedly detected in multiple environments for specific trait were further identified, among which six loci were reported for the first time in this study, and the remaining nine loci located in the previously identified quantitative trait loci (QTLs) or/and no more than 2 Mb with the known SNPs related with PH and EH traits. A total of 83 genes were annotated in the confidence intervals of the 15 stable SNPs, and the most likely candidate genes were further predicted according to the gene functional annotations and comparison with previous reports. The candidate genes were mainly involved in hormone synthesis and signal transduction, carbohydrate metabolism, cell division regulation and so on. Finally, six major SNP loci and one locus that affected PH, EH, and EH/PH simultaneously were identified. This study can provide genetic loci for molecular marker-assisted selection in maize breeding and provide valuable information for fine mapping and cloning of PH and EH related genes.

Early-senescence mutants are genetic materials important for the researches on the molecular mechanism of cell apoptosis in plants. An early-senescence mutant named esl8 (early senescence leaf 8) has been screened from the mutagenesis library of rice variety Kefujing 7. Compared with the wild-type control, the leaves of the esl8 mutant displays a severe of early-senescence phenotype at heading stage in rice, and its agronomic traits, including plant height, tiller number, grain length, grains per panicle, and seed setting rate, were obviously impaired except for the 1000-grain weight. In leaves of the esl8 mutant, the chlorophyll content was abnormally decreased, and the programmed cell death accompanied by excessive accumulation of the reactive oxygen species and the malondialdehyde were detected by histochemical staining. Genetic analysis indicated that the early-senescence phenotype of the esl8 mutant was controlled by a recessive nuclear gene. Based on the strategy of map-based cloning, the esl8 gene was finely mapped into a 359-kb region flanking by two molecular markers (FM12-14 and FM12-15) on chromosome 12. The prediction and verification of candidate genes by PCR sequencing confirmed that esl8 was a new variational allele of the OsSL/ELL1 gene. The sequence of mutation esl8 occurred in the conserved region of the corresponding wild-type gene. Our results provide a theoretical basis for further study on the biofunction and molecular mechanism of the protein encoding by ESL8 in early-senescence process.

Weighted Gene Co-expression Network Analysis (WGCNA) is a classic systems biology analysis method, which can be used to identify coexpressed gene modules and explore the biological correlation between modules and target traits, and mine core genes in module networks. In this study, 58 transcriptome data of roots, stems, leaves, and other tissues under low temperature stress, high temperature stress, drought stress, and salt stress in maize (Zea mays L.) were collected, and the gene co-expression network of maize abiotic stress was identified by WGCNA method. After filtering the 12,552 low-expression genes from transcriptome data, the co-expression network was constructed using the remaining 27,204 high-expression genes, and 25 modules were obtained. According to the distribution of abiotic stress-related genes and different expression genes in the modules reported in maize, the mediumpurple4, ivory, coral2, darkseagreen4 modules most related to low temperature stress, high temperature stress, drought and salt stresses, and green modules responding to various stresses were screened out. Subsequently, GO enrichment of the genes in these five modules revealed that genes with functions related to abiotic stress were significantly enriched in these modules, such as stress response, peroxidase activity. Correlation analysis showed that 10 abiotic stress-related core genes were predicted, including Zm00001eb072870, Zm00001eb320970, Zm00001eb037640, Zm00001eb423300, and Zm00001eb265310. This study provides new ideas for the mining of abiotic stress-related genes and the research of abiotic stress regulatory networks in maize.

CYP79 is a key enzyme in the synthesis of cyanogenic glycoside. However, there is no systematical study of CYP79 genes in flax. In this study, we identified CYP79 gene family in 9 crops including flax, and focused on the sequence characteristics, duplication events, collinearity, evolution, cis-acting elements and expression patterns of LuCYP79 genes. The results revealed that a total of 9, 9, 3, 2, 5, 7, 6, 16, and 4 CYP79 family members were identified in flax, pale flax, poplar, cassava, sesame, sorghum, soybean, grape, and rice, respectively. Phylogenetic analysis showed that the evolution of CYP79 genes was species-specific. LuCYP79 were distributed unevenly on four chromosomes and had 1-3 exons. The promoter region of LuCYP79 contained lots of elements involved in response to hormone and stress. 8 full-length DNA sequences and 5 full-length cDNA sequences of flax LuCYP79 genes were cloned. LuCYP79 proteins contained 282-565 amino acid residues with molecular weight of 31.56-62.86 kD, and isoelectric point of 5.84-9.14. All LuCYP79 members were hydrophilic protein and located in endoplasmic reticulum. There were five pairs of LuCYP79 genes with duplication events, accounting for 77.8% of all genes, and all the duplication genes underwent strong purification selection. Both LuCYP79-1 and LuCYP79-9 had homologous genes in Arabidopsis and cassava. The relative expression levels showed that LuCYP79 family members were tissue-specific and had different expression patterns under different genetic backgrounds. There were significantly different in the relative expression of LuCYP79-1, LuCYP79-7, LuCYP79-8, and LuCYP79-9 in the four cultivars. Moreover, correlation analysis showed that LuCYP79-1/LuCYP79-7 in 50 days flaxseed was significantly positively correlated with the concentration of cyanogenic glycosides in mature flaxseed. LuCYP79-7/LuCYP79-8 and (LuCYP79-7+LuCYP79-9)/LuCYP79-8 in 20 days flaxseed were significantly positively correlated with the concentration of cyanogenic glycosides in mature flaxseed, respectively. It was preliminarily speculated that they might be the key genes in the synthesis of cyanogenic glycoside in flaxseed. These results have positive significance for further elucidating the function of CYP79 proteins in flax and provide theoretical references for breeding flax varieties with low cyanogenic glycoside.

Functional molecular markers were designed based on nucleotide differences of known functional loci on Waxy (GBSSI), a regulation gene for amylose synthesis in proso millet. Genotypes and phenotypes of 270 proso millet accessions from Shanxi province were tested and verified by combining phenotypes and genotypes. The amylose content of 46 proso millet accessions with different genotypes was determined to explore the genetic effect of this gene and evaluate its breeding value. Waxy gene of proso millet existed in two forms (L and S), targeting 15 bp on S type gene. A functional marker was designed for InDel (RYW214), which could effectively distinguish 126 bp, 141 bp, and heterozygous (126/141 bp) types. The consistency between the marker and phenotypic identification was 93.30%, and the Pearson correlation index (r) was 0.745. Two CAPS markers (RYW215, RYW216) were designed for a single nucleotide insertion site and a SNP site in the L-type gene. Among 270 accessions, genotype S_-15/L_F accounted for the most (31.10%), S₀/S_-15/L_F was the second (22.96%), and S_-15/L_Y/L_F was the least (0.74%). Genotype S_-15/L_C was absent. Among 46 proso millet accessions, the genotypes with the highest mean amylose content were S₀/L_Y/L_F (15.50%) and S_-15/L_F (0.58%). The mutant alleles of L type gene had little effect on amylose content, and the existence of wild type S₀ was enough to guarantee amylose content in endosperm. The existence of mutant S_-15 would lead to a qualitative decline in amylose content, and the amylose content of heterozygous genotype S₀S_-15 was slightly higher than that of homozygous genotype S_-15.

The seed size of castor (Ricinus communis L.) directly affects the yield, and there is a great difference in seed size among different castor varieties. It is of great significance to further study the genetic mechanism of castor seed size traits for the development of castor seed industry. In this study, we used monoecious inbred lines SL1 as male parent, pistillate line HCH1 as female parent 1 (Combination 1), and pistillate line HCH3 as female parent 2 (Combination 2) to construct F₂ and BC₁ populations, respectively. Firstly, the correlations between seed size traits were analyzed by phenotypic statistics of the two genetic populations. Secondly, based on the phenotypic data of 150 individual plants in F₂ population from Combination 1, a high-density genetic map was constructed using genotyping by whole genome sequencing technology (WGS), and QTL analysis was performed for the seed size traits. Finally, the KEGG pathway enrichment and BLAST comparison were performed to determine the candidate genes in the definite QTL region. The results showed that the correlation between seed traits was different among different combinations and populations, and the correlation between seed length and width was the most significant by the phenotypic analysis. And a total of 18 QTLs were detected for four traits including 2 QTLs for seed length, 5 QTLs for seed width, 4 QTLs for seed thickness, and 7 QTLs for hundred-grain weight, which were distributed on linkage groups 1, 4, 7, 8, 9, and 10, respectively. The LOD values ranged from 3.77 to 7.40, and the contribution of variation rate ranged from 0.71% to 86.20%. Based on these results, six candidate genes (28470.m000435, 29908.m006143, 29848.m004589, 27752.m000045, 29683.m000480, and 29848.m004611) for regulating seed size were screened. This study lays a theoretical foundation for further research on fine mapping and gene cloning, molecular marker-assisted breeding and gene function analysis of castor seed size traits.

Rice grain size is a complex agronomic trait, controlled by multiple genes. Chromosome segment substitution lines are an effective method for creating natural occurring variations and are as the ideal materials for exploring the complex traits. In this study, a novel rice long-large grain chromosome segment substitution line Z66 was developed. Z66 contained 12 substitution segments from R225 (average substitution length was 3.32 Mb) based on the genetic backgrounds of Nipponbare. Then, 12 QTLs for rice grain size were identified by the secondary F₂ population from Nipponbare/Z66, and 5 novel single-segment substitution lines (SSSLs, S1-S5), and 4 novel double-segment substitution lines (DSSLs, D1-D4) harboring target QTL were developed. Among them, 9 QTLs (qGL3, qGL7, qGL10, qGW6, qGW10, qRLW3, qRLW10, qGWT3, and qGWT10) could be verified by the SSSLs, indicating that these QTLs were genetically stable. In addition, 6 novel QTLs (qGL9-2, qGW9-2, qRLW6, qRLW7, qRLW9-2, and qGWT7) were detected by the SSSLs. Among 18 QTLs, 5 QTLs (qGL9-2, qRLW9-1, qRLW9-2, qGW9-2, and qGWT9-2) might be novel. Target QTLs pyramiding showed that the pyramid of different QTLs had various epistasis effects. For example, the pyramids of qRLW3 (a=0.21) and qRLW9-2 (a=0.08) produced an epistasis effect of 0.10, which made the ratio of grain length to width in D2 significantly larger than that in Nipponbare, S1 (qRLW3), and S4 (qRLW9-2). The pyramid of qGWT3 (a=3.99) and qGWT10 (a=3.98) yielded an epistasis effect of -5.35, and its genetic effects in D3 (2.62 g) significantly increased 1000-grain weight of D3 than in Nipponbare, but significantly decreased than that in S1 (qGWT3) and S5 (qGWT10). Understanding the interaction effects between target QTLs can predict the phenotype of futural QTL pyramid genotypes, which is important for intelligent design breeding in rice.

Flag leaf is the main photosynthetic organ in wheat. The chlorophyll content is not only the major photosynthetic pigment in flag leaf but also an important phenotypic indicator in crop breeding. Therefore, the identification of major loci/genes related to chlorophyll content in the flag leaf play an important role in breeding wheat varieties with higher grain yields and stability. In this study, we constructed a double haploid (DH) population from a cross of two cultivars with significant difference in chlorophyll content, and the chlorophyll contents of DH lines were detected under five environments. A total of 20 QTLs associated with chlorophyll content were detected using Wheat 90K single-nucleotide polymorphism (SNP) array, with contributions to phenotypic variation explained (PVE) from 4.10% to 27.16%. Three QTLs (Qchl.saw-2D.1, Qchl.saw-4D.2, and Qchl.saw-6A) were identified under multiple environmental conditions, in which Qchl.saw-2D.1 with the strongest genetic effect was different from previous studies and identified as a novel major QTL. Furthermore, Qchl.saw-2D.1 was validated by a tightly linked kompetitive allele specific PCR (KASP) marker in a recombinant inbred line (RIL) population containing the co-parent Jinmai 919. Those lines with the favorable allele of Qchl.saw-2D.1 revealed significantly higher chlorophyll content than other lines under multiple environments. Moreover, a total of 12 candidate genes controlling chlorophyll content were identified in the three QTL regions. Based on gene annotation, three genes were involved in the binding process of metal iron, such as magnesium. Five genes were regulated the structural composition of chloroplasts, and four genes were engaged in the regulation of electron transfer activities during the photosynthetic process. In conclusion, this study will broaden the understanding of the genetic mechanism and provide a molecular basis for the marker-assisted breeding (MAS) of chlorophyll content in the flag leaf of wheat.

It is of great theoretical and practical significance to study the dry matter accumulation and translocation properties of ratoon rice for further understanding the physiological mechanism of yield formation and exploring the potential of yield increase. In this study, two rice varieties, Jiafuzhan (conventional indica rice) and Yongyou 2640 (indica-japonica hybrid rice), popularly planted in Southeast China, were used as the test materials. The ratooning and main rice crops of the two cultivars were regulated to be heading and ripening in the similar temperature condition of late autumn. Differences of photosynthetic physiology, hormone content, dry matter production, NSC translocation, and ¹³C assimilate in aboveground and underground parts of ratooning rice and its main crop synchronized heading in late season were compared. The results showed that, compared with main crop (late season) synchronized in rice heading time, the growth period of ratooning rice of the two varieties was 50% shorter, but they had 50% increase of effective panicles and 10% increase of harvest indexes, so the final yield could still reach 55%-65% of the control yield; the photosynthetic rate and SPAD value of the ratooning rice at the early stage of grain filling were significantly higher, but they turned to be significantly lower from 20 days after full heading to maturity; the content of ZR and IAA in ratooning rice were higher at the full heading stage, but lower later; the content of ABA in ratooning rice was 10%-20% higher from full heading stage to 10 days or 20 days after full heading, while the content of GA₃ in ratooning rice was generally lower; NSC translocation rates of stubble, leaf and stem-sheath of the two tested varieties were as high as 67%-78%, 59%-67%, and 52%-61%, respectively, and the contribution rate of NSC translocation to yield was also as high as 10%-18%, respectively. The distribution rate of ¹³C photochemical compounds in panicle of ratooning rice at maturity stage was up to 20.83%, and the translocation of ¹³C assimilates to underground part of ratooning rice was reduced by 5%, resulting in more effective panicles and higher harvest index. Therefore, ratooning rice can reduce translocation and allocation of photoassimilates to rhizosphere soil, improve harvest index, lessen CH_4, and other greenhouse gas emissions, which is a high-benefit and environment-friendly rice cropping pattern.

The application of nitrogen (N), phosphorus (P), and potassium (K) fertilizers is an important measure to increase yield in agricultural production. Continuous upland and paddy-upland anniversary multiple cropping rotation is the main planting mode of winter oilseed rape in the Yangtze River basin in China. In order to explore the effects and differences of N, P, and K on the yield and nutrient absorption and utilization of rapeseed in different rotations, a field experiment was carried out in Shayang County, Hubei Province for 3 years from 2017 to 2020. Two rotation modes of upland-oilseed rape (maize-rape) and paddy-oilseed rape (rice-rape) were adopted, and four treatments of nitrogen, phosphorus and potassium combined application (NPK), no nitrogen (-N), no phosphorus (-P), and no potassium (-K) applications on the basis of NPK were set in each rotation. The yield, yield components, and nutrient uptake of rapeseed were analyzed, the fertilizer use efficiency and soil indigenous nutrient supply were evaluated. The average results of the three-year trials showed that, compared with the NPK treatments, the -N, -P, and -K treatments in upland reduced rapeseed yields by 68.4%, 89.6%, and 7.0%, and by 71.0%, 84.7%, and 6.4% in paddy fields, respectively. Among the yield components, whether it was upland or paddy, fertilization had the greatest impact on the number of siliques, followed by the number of grains per silique, and had the least impact on the thousand-grain weight. Compared with NPK treatment, the number of siliques in upland and paddy fields was decreased by 61.6% and 52.0%, 82.0% and 67.8%, 16.2% and 19.7% due to N, P, and K deficiency, respectively. There were significant differences in the yield and nutrient absorption of rapeseed in upland and paddy field under different fertilization treatments. The yield of rapeseed in upland was about 27.2%, 15.2%, and 16.7% higher than that in paddy field in the -N, -K, and NPK treatments, while the yield of paddy rapeseed under -P treatment was 20.8% higher than that of upland. Nutrient accumulation trends were similar to the yield, except for -P treatment, the accumulation of N, P, and K in the upland oilseed rape under NPK treatment was 20.4%, 37.3%, and 4.2% higher than paddy oilseed rape, respectively. The soil indigenous N and K supply in upland was 15.0% and 20.9% higher than that in paddy field, while the supply of P in upland was 39.2% lower than that in paddy field. The recovery efficiency of N and P in upland were higher than that of paddy field, while K recovery efficiency was lower than that of paddy field. In summary, the combined application of nutrients could improve rapeseed yield and nutrient use efficiency. The significant differences in rapeseed yield and nutrient utilization among different crop rotations were affected by nutrient types. Compared with the upland, to supplement the nutrients deficiency in the soil and achieve high-yield and high-efficiency production of rapeseed, rapeseed in paddy fields needs to pay more attention to the application of N and K fertilizers, while rapeseed in upland needs to be appropriately increased in P fertilizers compared with paddy fields.

In order to explore the effects of supplemental irrigation with micro-sprinkling hoses and water and fertilizer integration on yield and water and nitrogen use efficiency in winter wheat, different water and fertilizer management models were tested in winter wheat growing season from 2019 to 2021. Taking Shannong 29 as the experimental material and adopting the split zone design, two main areas of border irrigation (W1) and supplemental irrigation with micro-sprinkling hoses (W2), and two sub areas of uniform nitrogen supply with water during jointing (T1) and local nitrogen supply with furrow and strip application (T2) were set. The results showed that compared with W1 treatment, the irrigation amount during the whole growth period of W2 treatment decreased by 53.3 mm and 45.9 mm, saving water by 35.5% and 30.6% in two years, respectively. Under the same irrigation mode, the content of soil nitrate nitrogen in 0-80 cm soil layer at flowering stage and 0-120 cm soil layer at maturity stage in T2 treatment was significantly higher than that in T1 treatment. In W1 mode, the content of soil nitrate nitrogen in 0-30 cm soil layer of T1 treatment at flowering and maturity stages was significantly higher than that in non-fertilization row of T2 treatment, the root length density and root surface area density in 0-100 cm soil layer at flowering and maturity stages were significantly higher than those in fertilization row and non-fertilization row of T2 treatment, the root activity, nitrogen assimilation, and nitrogen transport from vegetative organs to seeds in 0-20 cm soil layer after flowering. There were no significant differences in nitrogen partial productivity, nitrogen use efficiency, water use efficiency, and grain yield between T2 treatment and T2 treatment. Under W2 mode, the soil nitrate nitrogen content of 0-60 cm soil layer in T1 treatment at flowering and maturity stages was significantly higher than that of non-fertilization row in T2 treatment. The root length density and root surface area density of 0-100 cm soil layer at flowering and maturity stages were significantly higher than that of fertilization row and non-fertilization row in T2 treatment. The root activity, nitrogen assimilation, nitrogen transport from vegetative organs to seeds in 0-20 cm soil layer after flowering, nitrogen uptake efficiency, nitrogen use efficiency, nitrogen partial productivity, water use efficiency, and grain yield were significantly higher than those of T2 treatment. In conclusion, the above results showed that under the condition of traditional border irrigation, there was no significant difference in grain yield, water and nitrogen use efficiency between uniform nitrogen supply with water and topdressing at jointing stage and local nitrogen supply with furrow and strip application. Under the condition of micro spray supplementary irrigation and water saving, the uniform nitrogen supply with water and topdressing at jointing stage was significantly better than the local nitrogen supply of furrow and strip application. The integration of supplemental irrigation with micro-sprinkling hoses and topdressing of fertilizer (supplemental irrigation with micro-sprinkling hoses + uniform topdressing nitrogen with irrigation water at jointing stage) optimized the spatial distribution of soil nitrate nitrogen, which could maintain a high nitrogen supply level in the middle and late growth stage of wheat, significantly improve the absorption area and intensity of roots, and increase the amount of nitrogen assimilation and nitrogen transport from vegetative organs to grains after flowering, thus grain yield, water and nitrogen use efficiency were improved simultaneously.

The coordination of shoot and root is essential for the growth and development in maize. Analyzing the effect of the planting density on the shoot and root coordinated development can provide a new perspective for the theory and technology of increasing planting density and yield improvement. The experiments were conducted in 2020 and 2021 at the experimental station of Institute of Crop Sciences, the Chinese Academy of Agricultural Sciences, Gongzhuling, Jilin province. Two densification resistant varieties (Zhengdan 958 and Xianyu 335) and two planting densities (D1: 67,500 plants hm^-2; D2: 97,500 plants hm^-2) which were in the production stability interval were set up in this study, and the difference of some indexes of root and shoot was analyzed at different growth stages. The results showed that, compared with D2, the dry matter and root dry weight per plant of maize decreased significantly, while some population indexes were different. Among them, the yield of two varieties were not significantly increased. When the root indexes reached the maximum value on the 15th day after silking (R2 stage), the root dry weight per area, root length density did not increase significantly. The dynamic of shoot root ratio (S/R) during growth period could be expressed by exponential equation (y=ae^bx), and the increasing planting density significantly increased the S/R, grain root ratio, and leaf area root ratio. The increase of the three ratio at high density provided a signal of intensified root survival pressure. The results showed that the response of maize root to planting density was different from that of shoot. Under the premise of the same yield level, choosing the planting density with less root pressure may be more conducive to the construction of shoot and root coordination and constructing reasonable maize population.

Soil moisture and nitrogen nutrient are the two principal factors affecting rice production. Alternating dry and wet irrigation (AWD) coupled with nitrogen application plays important roles in root growth and yield formation in rice. However, its effect on grain filling physiology and their relationship with root physiology is not clearly understood. To explore the effects of alternating dry and wet irrigation and nitrogen application coupling on grain filling, changes of key enzyme activities involved in sucrose-to starch conversion and hormone contents, and root physiology of rice, the super rice variety Nanjing 9108 was cultivated as the material in the field. The field experiments were conducted with two irrigation regimes [conventional irrigation (CI) and AWD] and five nitrogen application rates [no nitrogen fertilizer (0N), 90 kg hm^-2 (90N), 180 kg hm^-2 (180N), 270 kg hm^-2 (270N), and 360 kg hm^-2 (360N) nitrogen fertilizer]. The results showed that there was a significant interaction effect between irrigation method and nitrogen application rate. Alternating dry and wet irrigation increased the maximum grain filling rate and average grain filling rate of Nanjing 9108, and increased the activities of the sucrose synthase enzymes, adenosine diphosphate glucose pyrophosphorylation enzymes, starch synthase enzymes, and starch branching enzymes, and the contents of zeatin + zeatin riboside, 3-indoleacetic acid and abscisic acid, increased root oxidation activity, and the content of zeatin + zeatin riboside in roots after heading, promoted the transfer of NSC stored in the stem sheath to the grain in the early growth stage of rice, and the highest yield was obtained after coupling with 270N, which was the best water-nitrogen coupling mode in this experiment. In conclusion, the water-nitrogen coupling effect can be exerted by appropriate regulation of water and fertilizer, which can improve the physiological performance of rice roots and grain-filling physiological activity, and achieve high rice yield.

The objective of this study is to investigate the response mechanism of nitrogen fertilizer to starch synthesis in wheat grains under high temperature stress after anthesis and to clarify the physiological mechanism and reasonable operation measures of nitrogen fertilizer to alleviate the damage of high temperature stress. The experiment was carried out in Jinan and Jiyang experimental station of Shandong Province on different nitrogen application rates (N1: 180 kg hm^-2, N2: 240 kg hm^-2, and N3: 300 kg hm^-2), with heat resistant wheat variety JM44 and heat sensitive variety XM26 from 2018 to 2020, using an artificial greenhouse to warm up the air temperature for 7 days after anthesis as high temperature stress (H) and the field as control (CK). Grain filling rates, grain weight, sucrose, starch synthesis and related enzyme activities were analyzed. The results showed that the grain filling period was shortened, the maximum grain filling rate, amylopectin content, total starch contents, and the ratio of amylopectin to amylase were significantly reduced compared with the control caused by high temperature stress after anthesis. Compared with 180 kg hm^-2 and 300 kg hm^-2 treatments, the sucrose accumulation in flag leaves were found highest in 240 kg hm^-2 treatment under high temperature stress. The contents of amylase, amylopectin, total starch, grain weight, the highest activity of sucrose synthase decomposition direction (SS-I), soluble starch synthase (SSS), and starch branching enzyme (SBE) in grains were also the highest in 240 kg hm^-2 treatment under high temperature stress. The results also showed that under high temperature stress with nitrogen application rate of 240 kg hm^-2 the activity of sucrose synthase synthetic direction (SS-II), and the activity of sucrose synthase decomposition direction (SS-I), the soluble starch synthase (SSS), and the starch branching enzyme (SBE) of grains in JM44 were higher than those in XM26, resulting in more sucrose content in flag leaves, higher grain weight, and more starch content of grains in JM44. The study showed that to reduce the inhibition on starch synthesis, the nitrogen application rate of 240 kg hm^-2 could maintain higher level of sucrose synthesis in flag leaves and sucrose decomposition capacity in grains after high temperature stress. These results indicate that the suitable nitrogen application and selection resistance cultivars were a coping measure to increase the starch content and alleviating the harmful effects of high temperature stress after anthesis in winter wheat.

Abstract: To exploit the difference of root nodule growth and nitrogen fixation potential of soybean in maize-soybean relay strip intercropping system, a two-year filed experiment with different nodulation characteristics soybean varieties (Gongxuan 1, Guixia 3, and Nandou 25) under different maize-soybean spacing (30, 45, 60, and 75 cm) was conducted. The results showed that the peaks of soybean nodule number and fresh weight were delayed under the intercropping system compared with soybean monoculture. The root nodule number and fresh weight of each variety under 60 cm were significantly higher than those of other spacing treatments, and were higher than those of monoculture soybean after reaching the peak stage. The differences among varieties were as follows: Nandou 25 > Guixia 3 > Gongxuan 1. Compared with soybean monoculture, nitrogen fixation potential of soybean nodules per plant before the beginning seed stage (R5) under intercropping mode was reduced. However, nitrogen fixation potential per plant of Gongxuan 1, Guixia 3, and Nandou 25 increased by 8.53%, 16.40%, and 13.70% on average in two years under 60 cm at R5 stage. The accumulation process of inclusions in infected cells of different soybean varieties was quite different. Compared with soybean monoculture, the number of bacteroids increased under 60 cm at R5, among which poly-β-hydroxybutyrate (PHB) increased, and Nandou 25 was the best. Therefore, to improve the number of soybean nodule bacteroids, PHB and nitrogen fixation potential the appropriate inter-plant row spacing (60 cm) under intercropping can increase soybean nodule number and fresh weight at R5 stage, and Nandou 25 with strong nodulation had the best effect.

Post-anthesis delayed leaf senescence and stay-green leaf phenotype are typically associated with the increasing yield, which offers the potential to increase crop resilience to drought stress. Retarded leaf senescence is beneficial to maintain cereal yield adaptability and stability. Many different management approaches, including fertilization, can modulate leaf senescence as well. The impacts of different long-term fertilization treatments on sorghum post-anthesis leaf senescence, antioxidant enzyme activities, and the yield were explored in 2020 and 2021 in this study. There were five treatments, which included chemical fertilizers of NPK (NPK), NPK plus manure (NPKM), NPK plus manure and straw returning (NPKMS), manure plus straw returning (MS), and fertilizer withdrawn (CK). Fertilizer application enhanced green leaf area per plant, SPAD reading and specific leaf nitrogen (SLN) compared with the control. Compared with NPK, the treatments of NPKM, NPKMS along with MS delayed post-anthesis attenuation of leaf area per plant and enhanced the values of SPAD and SLN in spite of the similar N application for NPK and MS. The treatments of NPK, NPKM, NPKMS, and MS increased antioxidant activities of SOD, POD, and CAT conjugate with a decreasing MDA content compared with the control. Among those, higher antioxidant enzymes activities and lower MDA content were induced by NPKM, NPKMS, and MS than NPK. In conclusion, NPKM, NPKMS, and MS promoted sorghum grain yield due to the increased grain number per panicle. Therefore, long-term application of manure combined with straw returning can not only replace chemical fertilizer but also delay leaf senescence, which leading to high grain yield in sorghum.

Rapeseed (Brassica napus L.) is an important oilseed crop in China, with high yield and nutritional value. Exploring the mechanism of the broad-spectrum stress regulatory genes plays key roles for improving stress resistance, yield, and quality in rapeseed. Mitogen-activated protein kinase (MAPK) cascades are the junctions of several transmembrane signaling, and are involved in a wide variety of biological processes, including growth, development, biotic, and abiotic stress responses. In order to survey the biological function of BnMAPK1 gene in rapeseed, BnMAPK1-overexpression (OE) and Zhongyou 821 (CK) plants were used as the experimental materials to perform the digital gene expression profiling sequencing at one-month-old seedling stage. Compared with CK, a total of 650 differentially expressed genes were obtained in OE plants, including 243 up-regulated genes and 407 down-regulated genes. GO annotation showed that differentially expressed genes were mainly enriched in 118 pathways in biological process, among which 18 pathways related to photosynthesis (with 77 differentially expressed genes). There were seven pathways in molecular function such as oxalate oxidase activity, manganese ion binding, and oxidoreductase activity; and 38 pathways in cellular component such as chloroplast, plastid, and thylakoid. KEGG indicated that BnMAPK1 was involved in regulating 14 pathways in rapeseed, including photosynthesis, carbon metabolism, and biosynthesis of secondary metabolites. In addition, the relative expression levels of eight candidate genes were validated by qRT-PCR in OE and CK in rapeseed, demonstrating that the expression changes of these eight genes were generally consistent with the sequencing data. Our findings lay a foundation for the function of BnMAPK1 in growth and development and light response in rapeseed and provide a theoretical basis for genetic breeding of crop resistance.

Peanut is one of the important oil crops. Its kernel quality directly affects its processing characteristics and is an important index for peanut quality evaluation. Establishing a high-throughput phenotyping model for peanut kernel quality and evaluating peanut kernel quality quickly and efficiently might significantly improve the efficiency of peanut breeding. In this study, the spectra of 175 peanut kernel samples (140 RIL populations derived from Yuhua 14 × LOP 215 and 35 other breeding lines) were collected by Antaris II Fourier Transform Near Infrared Spectroscopy Analyzer (Thermo company), and the oil content, protein content, sugar content, and fatty acid content of seed kernel were determined by Soxhlet extraction method, Dumas nitrogen method, anthrone colorimetry, and gas chromatography, respectively. Partial least squares (PLS) was used to construct the near-infrared calibration models of oil content, protein content, sugar content and some fatty acid content of peanut kernel. 30 other peanut materials which were not involved in the modelling were selected to verify the model externally. The determination coefficients (R²) of the models were greater than 0.90, indicating that the models could be applied to the high-throughput prediction of peanut kernel quality traits. This study provides a detection platform for high-throughput phenotypic analysis of peanut kernel quality traits.