糜子核心种质成株期抗旱性鉴定评价与抗旱种质筛选

Identification and Evaluation of Drought Tolerance and Screening of Drought-Tolerant Germplasm for Core Germplasms in Proso Millet at Adult Stage

【目的】干旱是影响糜子生长发育及产量的主要制约因素之一,筛选优异抗旱资源及鉴定指标,为抗旱品种的选育和抗旱分子机制的研究奠定基础。【方法】以200份糜子核心种质资源为研究对象,于2021—2022年在甘肃敦煌连续开展2年的田间成株期抗旱性鉴定,试验设置正常灌水和干旱胁迫2个处理,测定叶面积(leafarea,LA)、主茎直径(mainstem diameter,MSD)、主茎节数(number of main stem nodes,NMSN)、主穗长(main panicle length,MPL)、穗下节间长度(pedunclelength,PL)、株高(plantheight,PH)、单株草重(strawweightperplant,SWPP)、单株穗重(panicleweight perplant,PWPP)、单株粒重(grainweightperplant,GWPP)、千粒重(thousandgrainweight,TGW)和小区产量(yield perplot,YPP)11个指标,采用综合抗旱系数(CDTC值)、抗旱指数(DRI值)和抗旱性度量值(D值)对糜子成株期抗旱性进行综合评价。【结果】在不同水分处理条件下,叶面积、主茎直径、主茎节数、主穗长、穗下节间长度、株高、单株草重、单株穗重、单株粒重、千粒重和小区产量11个指标在不同种质间均表现为显著差异。干旱胁迫处理下,糜子的生长受到抑制,11个指标测定值均较正常灌水处理明显降低,且小区产量对干旱胁迫较敏感。相关性分析发现,11个测定指标的抗旱系数间均呈现出一定的相关性,其中,单株穗重和单株粒重的相关性最强,相关系数为0.943。主成分分析将11个鉴定指标转换成6个主成分,累计方差贡献率达80.667%。基于CDTC值、DRI值和D值的糜子资源抗旱性排序基本一致。根据D值利用聚类分析将200份糜子种质资源抗旱性划分为4类,第Ⅰ类为强抗旱型有10份,第Ⅱ类为抗旱型有70份,第Ⅲ类为干旱敏感型有81份,第Ⅳ类为干旱极敏感型有39份。株高、单株粒重、单株穗重和主穗长与D值的相关性较高,相关系数分别为0.756、0.697、0.696和0.679。通过逐步回归分析构建了糜子成株期抗旱评价的回归方程:Y=-1.509+0.362X1+0.174X2+0.349X3+0.389X4+0.307X5+0.251X6+0.218X7。【结论】抗旱性度量值法适宜于糜子成株期抗旱性评价;筛选出巴林左疙塔黍(00000525)、高台乌糜子(00002677)和民乐红糜子(00002687)等10份强抗旱性材料;株高、单株穗重和主穗长可作为糜子成株期抗旱性鉴定的主要指标。

【Objective】Drought is one of the major constraints influencing on the growth,development,and yield of proso millet.To screen excellent drought-tolerant accessions and identification indicators will promote the drought-tolerant varieties breeding and drought tolerance molecular mechanisms analysis of proso millet.【Method】In this study,200 core germplasm accessions of proso millet were used to identify field drought tolerance at adult stage in 2021-2022 at Dunhuang,Gansu province,with two treatments of normal irrigation and drought stress.Eleven morphological indicators,such as leaf area(LA),main stem diameter(MSD),number of main stem nodes(NMSN),main panicle length(MPL),peduncle length(PL),plant height(PH),straw weight per plant(SWPP),panicle weight per plant(PWPP),grain weight per plant(GWPP),thousand grain weight(TGW),and yield per plot(YPP)were determined.Comprehensive drought tolerance coefficient(CDTC value),drought resistance index(DRI value),and drought resistance comprehensive evaluation value(D value)were combined to identify the drought tolerance of proso millet at adult stage.【Result】There were significant differences in all eleven indexes among different accessions under different water treatments,including leaf area,main stem diameter,number of main stem nodes,main panicle length,peduncle length,plant height,straw weight per plant,panicle weight per plant,grain weight per plant,thousand grain weight,and yield per plot.The growth of proso millet was inhibited under drought stress treatments.Compared with the normal irrigation treatments,all the eleven indexes under drought treatments were significantly reduced,and yield per plot was more sensitive to drought treatments.The correlation analysis found that certain degrees of correlation existed among the drought tolerance coefficients of all traits,the correlation between panicle weight per plant and grain weight per plant was strongest,with a correlation coefficient of 0.943.Eleven evaluation indexes were converted into six comprehensive indexes by principal component analysis,with a cumulative variance contribution of 80.667%.The drought tolerance ranking of proso millet accessions based on CDTC value,DRI value and D value was generally consistent.The 200 proso millet accessions were classified into four categories according to D value cluster analysis,10 of clusterⅠwere highly drought tolerant,70 of clusterⅡwere drought tolerant,81 of clusterⅢwere drought sensitive,and 39 of clusterⅣwere highly drought sensitive.Plant height,grain weight per plant,panicle weight per plant and main panicle length were highly correlated with D value,with correlation coefficients of 0.756,0.697,0.696 and 0.679,respectively.The regression equation for the drought tolerance evaluation was constructed by stepwise regression analysis:Y=-1.509+0.362X1+0.174X2+0.349X3+0.389X4+0.307X5+0.251X6+0.218X7.【Conclusion】The drought resistance comprehensive evaluation value method could be suitable for evaluating the drought resistance of proso millet at adult stage.Ten accessions with highly drought tolerance,such as Balinzuogedashu(00000525),Gaotaiwumizi(00002677)and Minlehongmizi(00002687).Plant height,panicle weight per plant and main panicle length could be used as primary evaluation indexes for drought tolerance of proso millet at adult stage.