48份玉米种质的耐旱性鉴定与评价

Identification and evaluation on drought tolerance of 48 maize inbred lines

【目的】鉴定48玉米种质资源耐旱性,为玉米耐旱品种选育及种质材料创新提供参考。【方法】在防雨大棚条件下于玉米喇叭期进行35 d的自然干旱处理,调查48份玉米自交系在正常供水和干旱胁迫下的果穗性状、植株性状及产量;以产量抗旱系数（DC）、产量抗旱指数（DI）、产量抗旱隶属度（SV）为评价指标,结合主成分分析对玉米种质耐旱性进行综合评价和聚类分析。【结果】在干旱胁迫下,48份玉米自交系的平均株高、穗位高、叶面积、茎粗、穗长、穗粗、穗行数和行粒数分别比正常供水条件下降低14.8%、11.7%、6.4%、9.0%、12.0%、2.5%、4.6%和16.6%,产量降幅为11.0%~59.8%。运用DC、DI和SV进行综合评价,筛选获得较耐旱自交系15个,不耐旱自交系11个。各抗旱性评价参数与玉米种质的产量、行粒数、穗长和穗粗等性状的相关性较明显,与株高、穗位高、叶绿素SPAD值、叶面积、茎粗和百粒重等相关性较低。主成分分析结果表明,DI、SV、产量、行粒数、DC和穗长等是玉米自交系抗旱性评价的重要指标;以上述参数进行聚类分析,结果表明,可将48份玉米种质聚为四大类：第Ⅰ类有10份材料,表现较耐旱;第Ⅱ类可细分为两个亚类,第Ⅱ-1亚类包含11份材料,第Ⅱ-2亚类包含14份材料,其中第Ⅱ-2亚类中有5份自交系也较耐旱;第Ⅲ类包含1份材料,不抗旱;第Ⅳ类包含12份材料,较不耐旱。【结论】综合运用DC、DI和SV等评价参数并结合主成分分析和聚类分析对玉米自交系的耐旱性进行评价,结果较可靠;玉米产量、行粒数、穗长和穗粗等性状是生产中筛选耐旱种质的重要指标。

【Objective 】The drought tolerance of 48 maize inbred lines were identificated and evaluated in order to provide references for breeding drought-resistant maize varieties and innovating germplasm resources. 【Method 】Under the environment of rainproof greenhouse,two treatments were designed as normal watering and 35-day natural drought stress at flare opening stage. The ear traits,plant traits and yield of 48 maize inbred lines were investigated after 35 days of drought stress. The drought resistance of different materials were comprehensively appraised based on subordinate function values of drought resistance（SV）, drought coefficient（DC） and drought index（DI） of yield. The correlation analysis and principal component analysis were conducted according to ear traits, plant traits, SV, DC, and DI and so on. The cluster analysis of drought tolerance for 48 maize germplasms was conducted by using SV, DC,DI, yield, grains per row and ear length. 【Result 】Compared with normal watering condition, the average plant height, ear height,leaf area, stem diameter, ear length, ear diameter, rows per ear, grains per row of 48 maize inbred lines decreased by 14.8%, 11.7%, 6.4%, 9.0%, 12.0%, 2.5%, 4.6% and 16.6%, and the yield decreased by 11.0%-59.8%. Based on the evaluation results of yield DC, DI and SV, 15 inbred lines were of drought resistance, and 11 inbred lines were sensitive to drought. The yield DC, DI and SV showed higher correlation with yield,grains per row, ear length and ear diameter, and lower correlation with plant height,ear height,chlorophyll SPAD value, leaf area, stem diameter and 100-grain weight. The principal component analysis showed that DI, SV, yield,grains per row, DC and ear length were the important evaluating indices of maize drought tolerance, which could be used for cluster analysis. The cluster analysis indicated that 48 maize inbred lines could be classified into four groups, category Ⅰ included 10 drought tolerant inbred lines; category Ⅱ included two subgroups, subgroup Ⅱ-1had 11 inbred lines,subgroup Ⅱ-2 had 14 inbred lines, out of which, 5 inbred lines were of drought tolerance.Group Ⅲ only included one drought sensitive inbred line, group Ⅳ included 12 drought sensitive inbred lines. 【Conclusion 】It indicated that yield DC, DI and SV combined with principal component and cluster analysis are reliable to comprehensively evaluate drought resistance of maize inbred lines. The yield, grains per row, ear length and ear diameter were the important indices for selection of drought tolerance germplasm in production.