| 1 | Identification and screening of nitrogenefficient cotton genotypes under low and normal nitrogen environments at the seedling stage显示文摘Background: Large quantities of nitrogen(N) fertilizer applied to cotton cropping systems support high yields but cause adverse environmental impacts such as N_20 emission and water eutrophication. The development of cotton cultivars with higher N use efficiencies suitable for low-N conditions is therefore important for sustainable production. In this study, we evaluated 100 cotton genotypes in 2016 for N use efficiency and related traits at the seedling stage.Methods: Sand culture experiment was conducted with low N levels(0.01 g·kg^(-1)) or normal N levels(0.1 g·kg^(-1)).We investigated plant height, SPAD value(soil plant analysis development chlorophyll meter), dry weight, N accumulation, N utilization efficiency, and N uptake efficiency. Through descriptive statistics, principal component analysis and heatmap clustering analysis, we confirmed the evaluation index system of N-efficient genotypes and the classification of N-efficient genotypes.Results: Significant differences were observed among N levels and genotypes for all agronomic traits and N levels.Coefficients of variation varied greatly and ranged from 6.7~28.8 and 7.4~20.8 under low-N and normal-N treatment, respectively. All traits showed highly significant positive correlations with each other, except SPAD value.The principal components under both N levels were similar, showing that total dry weight, aboveground dry weight, total N accumulation, and N uptake efficiency were important components. We confirmed these four traits as suitable screening indexes for low N tolerance. Based on the results of heatmap clustering and scatter diagram analysis of N efficiency value, 10 genotypes were found low-N tolerant, in which five varieties were inefficient under both low and normal N conditions, while four varieties were found efficient under low-N conditions but inefficient under normal-N conditions. Only one variety was efficient under both low and normal-N conditions. Meanwhile, 20 genotypes were identified as low-N sensitive ones, in which 19 genotypes were inefficient under low-N conditions but efficient under normal-N conditions, one variety was inefficient under both low and normal-N conditions.Conclusion: We preliminarily identified Kashi as a low-N tolerant and N-efficient cotton genotype, and CCRI 64 as a lowN sensitive and N-inefficient cotton genotype. Further studies should be carried out to verify the yield and heritability effect of specific genotypes in the field. | ZHANG Hengheng FU Xiaoqiong WANG Xiangru GUI Huiping DONG Qiang PANG Nianchang WANG Zhun ZHANG Xiling SONG Meizhen | 2018 | Journal of Cotton Research2018，1，2： | 9 |
| 5 | Chromosome-level genome assemblies of five Prunus species and genome-wide association studies for key agronomic traits in peach显示文摘Prunus species include many important perennial fruit crops,such as peach,plum,apricot,and related wild species.Here,we report de novo genome assemblies for five species,including the cultivated species peach(Prunus persica),plum(Prunus salicina),and apricot(Prunus armeniaca),and the wild peach species Tibetan peach(Prunus mira)and Chinese wild peach(Prunus davidiana).The genomes ranged from 240 to 276 Mb in size,with contig N50 values of 2.27−8.30Mb and 25,333−27,826 protein-coding gene models.As the phylogenetic tree shows,plum diverged from its common ancestor with peach,wild peach species,and apricot~7 million years ago(MYA).We analyzed whole-genome resequencing data of 417 peach accessions,called 3,749,618 high-quality SNPs,577,154 small indels,31,800 deletions,duplications,and inversions,and 32,338 insertions,and performed a structural variant-based genome-wide association study(GWAS)of key agricultural traits.From our GWAS data,we identified a locus associated with a fruit shape corresponding to the OVATE transcription factor,where a large inversion event correlates with higher OVATE expression in flat-shaped accessions.Furthermore,a GWAS revealed a NAC transcription factor associated with fruit developmental timing that is linked to a tandem repeat variant and elevated NAC expression in early-ripening accessions.We also identified a locus encoding microRNA172d,where insertion of a transposable element into its promoter was found in double-flower accessions.Thus,our efforts have suggested roles for OVATE,a NAC transcription factor,and microRNA172d in fruit shape,fruit development period,and floral morphology,respectively,that can be connected to traits in other crops,thereby demonstrating the importance of parallel evolution in the diversification of several commercially important domesticated species.In general,these genomic resources will facilitate functional genomics,evolutionary research,and agronomic improvement of these five and other Prunus species.We believe that structural variant-based GWASs can also be used in other plants,animal species,and humans and be combined with deep sequencing GWASs to precisely identify candidate genes and genetic architecture components. | Qiuping Tan Sen Li Yuzheng Zhang Min Chen Binbin Wen Shan Jiang Xiude Chen Xiling Fu Dongmei Li Hongyu Wu Yong Wang Wei Xiao Ling Li | 2021 | Horticulture Research2021，8，1： | 1 |
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