山西小麦苗期耐低磷特性及遗传分析

Seedling Characterization and Genetic Analysis of Low Phosphorus Tolerance in Shanxi Varieties

【目的】干旱与半干旱地区的水肥资源贫乏,而小麦不同基因型间的磷效率差异很大,因此,鉴选耐低磷种质、挖掘磷代谢遗传位点有助于小麦的遗传改良。【方法】以282份山西小麦品种为材料,在正常磷(0.2 mmol·L^(-1))、中度低磷(0.1mmol·L^(-1))和低磷胁迫(0.01 mmol·L^(-1))3个磷浓度条件下对苗期根部鲜重、茎叶部鲜重、植株鲜重、根部干重、茎叶部干重、植株干重,最大根长、总根长、根表面积、根体积、根直径和根尖数共12个形态指标进行考查,运用主成分分析、隶属函数分析及聚类分析等方法综合评价苗期不同品种的耐低磷特性,在此基础上,分析苗期性状演变趋势及生物量分配等特征,并利用全基因组关联分析挖掘小麦耐低磷位点。【结果】苗期不同性状对低磷的响应程度不同,磷浓度降低导致生物量分配策略发生变化,与根部生长情况比较,地上部生长受磷浓度变化影响小;磷浓度降低会抑制地上部生长,地上部干重和鲜重显著降低,而低磷促进了根系生长,根部干重和鲜重、最大根长、总根长、根体积和根尖数等指标显著增加。根据耐低磷综合D值与形态指标相关分析发现最大根长和根直径可作为苗期耐低磷的筛选指标,D值聚类分析筛选到晋麦46、晋麦61、有芒大红茎、红秃麦、红和尚、白壳红、白线麦、火烧头和白山麦共9份耐低磷品种。性状演变分析发现品种耐低磷能力没有受到直接选择。耐低磷能力随年代变化先降后升,2010年之前品种耐低磷能力呈下降趋势,2010年后品种耐低磷能力有所提升。关联分析检测到8个R^(2)>10%的稳定位点,其中,1A_545074550、2B_489279799、6A_166899658和6A_273060644未见报道。【结论】苗期最大根长和根直径可作为苗期耐低磷的筛选指标。通过综合评价山西小麦苗期耐低磷能力,筛选到9份耐低磷品种。在1A、2B和6A染色体上检测到4个与耐低磷相关的新位点。

【Objective】In arid and semi-arid regions,the water and nutrients are scarce in the soil.The phosphorus use efficiency between different wheat genotypes varies greatly.Therefore,identification of low phosphorus-tolerant germplasm and mapping of related loci is helpful for genetic improvement of wheat.【Method】Using 282 Shanxi wheat varieties as materials,twelve seedling morphological indicators were investigated under three phosphorus concentrations,including SDW,RDW,DW,SFW,RFW,FW,MRL,TRL,RS,RV,RD,and RN.Principal component analysis,membership function analysis,and cluster analysis were used to comprehensively evaluate the low phosphorus tolerance characteristics of different varieties at the seedling stage.On this basis,the trait evolution trend and biomass allocation at seedling stage were analyzed.At the same time,GWAS was used to identify significant loci related to the low phosphorus-related traits.【Result】The response of different traits to low phosphorus at the seedling stage was different.Lower phosphorus concentrations led to changes in biomass allocation strategy,and shoot growth was less affected by change in phosphorus concentrations than root growth.The decrease in phosphorus concentration inhibited the growth of shoot,and SDW and SFW were significantly reduced.In contrast,low phosphorus promoted root growth,and the indicators of RDW,RFW,MRL,TRL,RV and RN increased significantly.According to the correlation analysis between D-value and morphological indicators,it was found that MRL and RD could be used as selection indicators for low phosphorus tolerance at seedling stage.Based on D-value clustering analysis,9 low phosphorus tolerant varieties were selected,including Jinmai 46,Jinmai 61,Youmangdahongjing,Hongtumai,Hongheshang,Baikehong,Baixianmai,Huoshaotou,Baishanmai.Analysing trends in trait evolution showed that cultivars were not directly selected for their ability to tolerate low phosphorus.The ability to tolerate low phosphorus decreased first and then increased over time.Before 2010,there was a decreasing trend in the ability of varieties to tolerate low phosphorus,and after 2010,there was an increase in the ability of varieties to tolerate low phosphorus.GWAS stably detected eight loci with R^(2)>10%in three environments,in which 1A_545074550,2B_489279799,6A_166899658 and 6A_273060644 were not reported previously.【Conclusion】The MRL and RD can be used as selection indicators for low phosphorus tolerance at seedling stage.A total of nine varieties were selected through comprehensive evaluation of ability in Shanxi wheat to tolerate low phosphorus during seedling stage.Association analysis detected four novel loci associated with low phosphorus tolerance on chromosomes 1A,2B and 6A,and the results provide germplasm resources and QTL for future low phosphorus tolerance wheat breeding.