【Objective】Analyzing the yield and yield related traits of Sichuan wheat varieties from 2000 to 2020, providing reference for genetic improvement of yield in Sichuan wheat varieties. 【Method】From 2019 to 2022, a community trial design was used to measure the yield and related traits of 145 wheat varieties in Sichuan Province since 2001 to 2016, as well as 60 high-yield wheat varieties (Varieties with top yields in regional trials in Sichuan Province over the years) since 2000 to 2020. This data was used to analyze the trend of yield and yield related trait changes in Sichuan wheat cultivars cultivated from 2000 to 2020. 【Result】145 Sichuan wheat varieties from 2001 to 2016 have an average annual genetic gain of 37.20 kg·hm^-2 or 0.66% in yield. Grain number per spike and effective spike number per unit area showed an increasing trend, while thousand grain weight and plant height showed a decreasing trend. Correlation analysis showed that effective spike number per unit area was positively correlated with yield. Path analysis showed that the continuous increase of effective spike number per unit area (annual increase 0.42×10⁴/hm² or 0.13%) was the main factor for the increase of yield potential of high-yielding varieties. The average annual yield genetic gain of 60 high-yield wheat varieties from 2000 to 2020 was 61.10 kg·hm^-2 or 0.89%, the effective spike number per unit area showed an increasing trend, the plant height showed a decreasing trend, and the grain number per spike and thousand grain weight had almost no change. Correlation analysis shows that there was a significant positive correlation between yield and the number of effective ears per unit area. Path analysis showed that the continuous increase in effective spike number per unit area (with an average annual increase of 1.80×10⁴/hm² or 0.51%) was also a major factor in improving the yield potential of 60 high-yield wheat varieties in Sichuan from 2000 to 2020. 【Conclusion】The improvement and breeding of wheat yield heritage in Sichuan Province has made some progress, especially the improvement effect of high yield breeding is remarkable, and the yield level of wheat varieties in Sichuan Province is gradually increasing. The continuous increase in effective ears per unit area was the main factor for improving the yield potential of Sichuan wheat varieties. High grain number per spike and thousand grain weight are important foundations for high yield in Sichuan wheat, but their genetic improvement is in a bottleneck period. Increasing the effective spike number per unit area is the key to furtherly improve the yield of wheat in Sichuan.

【Objective】 Starch is the main component of wheat kernel and plays an important role in processing. The gelatinization characteristic of starch is an important index to evaluate its quality. The genetic variation of starch gelatinization was studied to provide basis for improving wheat quality. 【Method】 Seven starch gelatinization traits, including gelatinization temperature, peak time, peak viscosity, trough viscosity, final viscosity, decay value and recovery value, were phenotypically determined in 205 winter wheat varieties. Genome-wide association analysis was performed using 90K chip, and haplotype analysis was performed on the stable and significant sites found. 【Result】 The seven characteristics, such as pasting temperature, showed abundant variation in different environments, and the coefficient of variation of attenuation value was the largest (29.31%-31.14%). There were significant differences among genotype, environment and genotype × environment, and the generalized heritability was 0.69-0.86. Through genome-wide association analysis, we found 198 loci that showed significant associations with seven traits. It was distributed in 20 other linked groups except 6D chromosome. There were 58 sites that were stable in 2 or more environments, involving all 7 traits, such as pasting temperature (10), peak time (5), peak viscosity (12), trough viscosity (10), final viscosity (7), break down (4) and set back (10), which could explain 5.54%-22.21% of genetic variation, twenty-one new sites were identified. By haplotype analysis of multiple effector sites that exist in multiple environments and have high phenotypic contribution, Four haplotypes, Hap1 (66.84%), Hap2 (16.84%), Hap3 (9.70%) and Hap4 (6.63%), were found at Kukri_c17417_407 on chromosome 4A, which were significantly related to peak viscosity and break down. Where Hap2 is the peak viscosity and high break down. (P<0.0001). The distribution frequency of varieties (lines) containing haplotype Hap2 in different ecological regions was from high to low as Huanghuai winter wheat region>foreign varieties>Southwest winter wheat region>Middle and lower reaches of Yangtze River winter wheat region>Northern winter wheat region. There were 11 single cause multieffect sites, among which there were 3 multiple effect sites associated with final viscosity, set back, peak time and trough viscosity. Jagger_c4026_328 and other 11 stable genetic loci located on 1B, 2A, 3A, 3B, 4A, 4B, 5B and 6B were mined, and 11 candidate genes that might be related to wheat starch gelatinization traits were screened. 【Conclusion】 In this study, RVA parameters had high heritability, and the RVA parameters of wheat starch were different in different environments. In this study, RVA parameters had high heritability, and the RVA parameters of wheat starch were different in different environments. 58 stable loci were detected that were significantly associated with starch gelatinization traits, and 4 different haplotypes were identified on chromosome 4A that were significantly associated with peak viscosity and break down, and 11 candidate genes related to starch gelatinization were screened, which could provide help for marker-assisted high-quality wheat breeding.

【Objective】Canopy activity is an important indicator of wheat growth and development. Identification the loci for canopy activity related traits and their relationships with grain yield (GY) related traits can provide theoretical support for the dissection of genetic structure of yield trait and assisted wheat breeding.【Method】A total of 166 wheat varieties originating from both domestic and international sources were planted in Anyang of Henan province and Suixi of Anhui province in cropping seasons. With the integrated physical map containing 326 570 SNP markers from the wheat 90K and 660K chips, genome-wide association studies for normalized difference vegetation index at seedling stage (NDVI-S) and 10 days after flowering (NDVI-10), and chlorophyll content in flag leaf at 10 days after flowering (Chl-10) were carried out. The results were compared with the previous study for GY related traits using the same material. 【Result】Analysis of variance (ANOVA) showed highly significant effects (P<0.01) of genotypes, environments and genotype×environment interactions on NDVI-S, NDVI-10 and Chl-10, with broad-sense heritabilities (h2 b) of 0.81, 0.81 and 0.91, respectively. Thirteen, 12 and 15 loci were detected to be significantly correlated with NDVI-S, NDVI-10 and Chl-10, respectively, among which 12, 11 and 12 were new, and five loci were associated with two or more traits. The number of favorable alleles for NDVI-S, NDVI-10 and Chl-10 ranged from 4 to 11, 3 to 11 and 4 to 12, respectively, in the 166 wheat varieties, and the phenotypic values increased with the accumulation of favorable alleles. NDVI-S showed significant (P<0.01) and positive correlations with thousand-kernel weight, kernel length and kernel width. Chl-10 was significant positively correlated with GY and flag leaf width (P<0.01), whereas significant negatively correlated with spike number per unit area, plant height and uppermost internode length (P<0.01). Seven pleiotropic loci were detected co-related with both GY and canopy activity related traits.【Conclusion】NDVI-S can be directly used for selection of yield traits. The stable and pleiotropic loci detected in this study can be used for marker-assisted selection.

【Objective】 Cropping patterns are a summary of crop sequence which reflects the use patterns and efficiency of cropland resources. Through analyzing the phenological differences of different cropping patterns, the cropland phenology information atlas and cropping pattern spectrum for croplands on the Jianghan Plain were constructed, and the major cropping patterns in this area were mapped. 【Method】 The cropland phenology information atlas including different cropland use patterns was formed through expressing graphically the spatial difference between vegetation index states and cropland use patterns, according to the prior knowledge of crop planting and the phenological differences of different cropping patterns under the framework of geo-information atlas. Taking the major cropping patterns on the Jianghan Plain as the study cases, the vegetation index states in the key phenological periods were arranged and combined to establish the information remapping rule from the vegetation index states to the cropping patterns, their phenological characteristics were explored, and the cropping pattern spectrum was constructed. Then the data during the key phenological periods and phenological knowledge were integrated to map cropping patterns on the Jianghan Plain by using the Naive Bayes Networks. The vegetation index states of the key phenological periods were quantitatively expressed by using the knowledge probability coding method.【Result】The cropping pattern spectrum on the Jianghan Plain was constructed, and it was found that the cropping pattern spectrum on the Jianghan Plain was composed of eight cropping patterns: Spring single-cropping, Summer single-cropping, Spring-and-Summer double-cropping, Summer-and-Autumn double-cropping, double-cropping paddy-rice, cash crops, aquaculture ponds, trees or abandoned croplands. The results showed that the proposed cropping pattern spectrum and the method of mapping cropping patterns based on the key phenological periods and the Naive Bayesian Networks could extract all cropping patterns accurately, at the same time, which had good performance and suitability. There was a significant trend of the expansion of Summer-and-Autumn double-cropping and the shrink of Spring-and-Summer double-cropping and the Summer single-cropping on the Jianghan Plain during the study period.【Conclusion】The cropping pattern spectrum gave a picture of the overall situation of intensive utilization of croplands on the Jianghan Plain, for improving the accuracy of monitoring the use of croplands and enriching the connotation of the use of cropland resources.

【Objective】 This study was conducted to investigate the effects of alternating high temperature and drought on the content of Cry1Ac protein in Bt cotton and the underlying physiological mechanism, so as to provide a reference for the safe and stable utilization of insect resistance of Bt cotton in production.【Method】 The conventional cultivar Sikang 1 (SK-1) and hybrid cultivar Sikang 3 (SK-3) were used in 2019 and 2020 in experimentally controlled greenhouse, Yangzhou University. From 7:00 am to 7:00 pm, two high-temperature treatments [34℃ (A1) and 38℃ (A2)] were imposed on cotton plants, followed by an optimum temperature 28℃ during the remaining night hours. There were two treatments for soil moisture content, which were 50% (B1) and 60% (B2) field capacity. The treatment with 32℃/28℃ and 75% field capacity was set as the control (CK). The leaf Cry1Ac protein content and its physiological mechanism were detected on 4, 7, and 10 days after stress (DAS), respectively.【Result】 Compared with CK, the Cry1Ac protein content all decreased under the stresses of high temperature and drought, and with the extension of the stress time, greater decrease was observed. The extent of decline for A1B2 was the smallest, followed by A1B1, while A2B1 and A2B1 were the largest. The Cry1Ac protein content under A1B2 was significantly lower than CK after 7 DAS, while the significant differences between A1B1, A2B2, A2B2 and CK were detected after 4 DAS. The Bt gene expression level, soluble protein (SP), free amino acid (aa) contents, nitrate reductase (NR), the glutamic pyruvic transaminase (GPT), glutamic oxaloacetate transaminase (GOT), glutamine synthetase (GS) and glutamate synthase (GOGAT) activities showed a downward trend. While the tannin content, the activities of protease and peptidase showed an upward trend. The correlation analysis and path analysis showed SP, aa, NR, GPT, GOT, GS, and GOGAT were positively correlated with Cry1Ac protein content. The tannin content, activities of protease, and peptidase were negatively correlated with Cry1Ac protein content. NR, GPT and GS could be key indices for the Cry1Ac protein content.【Conclusion】 The interaction of high temperature and drought resulted in the decrease of Cry1Ac protein content in Bt cotton, with greater decrease observed as the stress extended. There was no significant difference between the treatment with 34℃/28℃ and 60% field capacity and CK in 7-10 DAS. The reduction extent of Cry1Ac for alternating high temperature regime and drought decreased and the period was delayed. NR, GPT and GS could be key indices for the Cry1Ac protein content.

【Objective】 Net anthropogenic nitrogen input (NANI) is one of the important causes to non-point source pollution. In order to investigate the spatio-temporal characteristics and influencing factors of net anthropogenic nitrogen input, the key source areas were identified and the key sources in watersheds were analyzed, so as to provide data support for solving the problem of non-point source nitrogen pollution. 【Method】 Three watersheds were selected according to their characteristics, among which Xiangxi River watershed was a typical agriculture watershed, Erhai watershed was comprehensively promotion model of green agricultural development, and Taihu watershed was a typical urban centralized watershed. Based on the NANI model, the data was obtained through statistical yearbook and literature review to evaluate NANI of the three typical watersheds.【Result】 In terms of NANI intensity, the average value of NANI in the three typical watersheds was ranked as follows: Taihu watershed (13 241 kg·km^-2·a^-1), Xiangxi River watershed (2 183 kg·km^-2·a^-1), and Erhai watershed (1 582 kg·km^-2·a^-1). In terms of NANI sources, nitrogen application (Nfer) and food/feed nitrogen (Nim) were the largest sources of NANI, accounting for 58%-97%. The NANI contribution ranked in the order of nitrogen application, food/feed nitrogen input, nitrogen deposition input, and crop nitrogen fixation input. In terms of time, food/feed nitrogen input of Xiangxi River watershed decreased by 23 percentage points from 2010 to 2019, while nitrogen deposition increased by 34 percentage points. From 2010 to 2019, nitrogen application in NANI decreased by 86 percentage points in Erhai watershed. From 2010 to 2019, the input of food/feed nitrogen to NANI in Taihu watershed increased by 31 percentage points, while the input of crop nitrogen fixation and nitrogen deposition decreased by 14 and 12 percentage points, respectively. In terms of influencing factors, NANI was significantly correlated with urban population density in the three typical watersheds (P<0.05), and NANI increased with the increase of urban population density. The Xiangxi River watershed had a significant effect on the proportion of cultivated land and NANI fitting (P<0.05), but the Erhai watershed and Taihu watershed was not significant effect (P>0.05)..【Conclusion】 Zhaojun town, Xiakou town and Huangliang town in Xiangxi River watershed, Xiaguan town, Shangguan town and Fengyi town in Erhai watershed, and Zhangjiagang City, Xiucheng District in Jiaxing City, Gongshu District and Nanhui District in Taihu watershed were the key source areas of NANI. Fertilizer application was the main source of NANI in Xiangxi River watershed where is mainly agricultural. The input of food/feed nitrogen and fertilizer nitrogen were the main sources of NANI in Taihu watershed where is mainly urbanization. The green agricultural development model could significantly reduce net anthropogenic nitrogen input. Therefore, it was beneficial to control agricultural non-point source pollution by vigorously promoting agricultural green development measures and effectively reducing the input of feed and fertilizer in key source areas.

【Objective】 The aim of this study was to identify members of the XTH gene family from peach, and to analyze the expression of PpXTHs in peach fruit with different textures during storage, which not only provided data for the research on the candidate PpXTHs involved in peach fruit softening, but also laid the foundation for further study on the PpXTHs function in peach fruit softening.【Method】 The HMM profiles of the Glyco_hydro_16 domain and XET_C domain were used to search all XTH proteins with the Hmmer 3.1 software in the peach protein database. The molecular weight, theoretical isoelectric point and other physicochemical properties were then predicted by the online tool ProtParam. PpXTHs subcellular localization were predicted by the online software Plant-mPLoc. The MEGA 11 software was used to construct a phylogenetic tree. The online tool MEME was used to analyze conserved motifs, the conserved motifs, conserved protein domains and gene structure maps were draw by Tbtools. According to the PpXTH gene family location information, chromosome mapping was carried out with MapChart software. The expressions of PpXTHs in peach fruit with different textures during storage were monitored by qRT-PCR..【Result】 A total of 27 PpXTH genes were systematically identified from peach, which were distributed on seven chromosomes. Based on the phylogenetic tree, the ancestral group, Ⅰ/Ⅱ subfamily, ⅢA subfamily and ⅢB subfamily were classified. In addition, according to the analysis of protein domains, all PpXTH gene family proteins had Glyco_hydro_16 and XET_C conserved domain. The results from qRT-PCR analysis showed that PpXTH33 belonging to the ⅢB subfamily was upregulated as the storage period increased in melting peach fruit, with the expression being markedly higher than that during the storage period of stony hard peach fruit. The positive clone sequencing was consistent with the coding sequence of the Prunus persica reference genome with a length of 924 bp for a 307 amino acid sequence. The PpXTH33 combined with green fluorescent protein may mainly located in the cell wall and nucleus detected by confocal laser scanning microscopy..【Conclusion】 All 27 PpXTHs protein structures contained two highly XTH conserved domains and the genes were distributed on seven chromosomes. The expression characteristics of PpXTH33 in peach fruit with different flesh textures during storage suggested that PpXTH33 was closely associated with peach fruit softening during storage.