大豆品种抗旱性早期鉴定方法

为探讨鉴定大豆品种抗旱性的简易方法,依据吸水后48h的发芽率对109个大豆种质材料进行抗旱性分级。继而在萌发期、营养生长期（V3）和生殖生长期（R4）进行盆栽控水试验,根据抗旱等级验证大豆植株的抗旱性。结果发现,大豆品种间抗旱性存在显著差异。种子吸水量与抗旱性无关,吸水后48h发芽率与抗旱性密切相关。幼苗侧根数量、主根长度和根系干重与抗旱性呈显著（P〈0.05）相关。对萌发后幼苗供水24h后,随即停水24h,反复干旱处理,抗旱品种存活率显著高于普通品种。在V3期对盆栽植株进行暂时萎蔫（土壤含水量为9%～11%）的水分胁迫处理,发现停水后普通品种叶片首先发生萎蔫,且株高、茎直径及叶面积下降的程度均高于抗旱品种。水分胁迫下,抗旱品种株高、茎直径和叶片面积均显著（P〈0.05）高于普通品种,其中茎直径和叶片面积达到极显著水平（P〈0.01）。在R4期暂时萎蔫的水分胁迫下,抗旱品种根的生物量和分枝的生物量显著（P〈0.05）高于普通品种。鼓粒期（R6）普通品种发生永久萎蔫、植株死亡,而抗旱品种仍能保持生长能力。研究结果表明,大豆种子48h发芽率可作为大豆品种抗旱性的鉴定和筛选方法,鼓粒期大豆对水分胁迫最敏感。

Early identification method of droughttolerance of soybean cultivars

A simple method of germination rate at 48hafterwaterabsorption was used and verified to investigate soybean drought-tolerance.The drought-tolerances of 109 soybean germplasms were graded according to seed germination rate at the germination stage,and then in pot watercontrol trails at vegetative growth （V3） stage and reproductive growth （R4） stage.Results indicated significant differences in droughttolerance of soybean materials.Water absorption made no difference to droughttolerance.However,germination rate of 48hafterwaterabsorption and droughttolerance were closely correlated.Seedling branch root number,main root length and root dry weight had significant （P〈0.05） positive correlation with droughttolerance.Under repeated stress of supplying water for 24h after germination and then no water for 24h,the survival rate of droughttolerant cultivars was higher than those of ordinary ones.At the vegetative growth stage （V3）,temporary wilting （under soil moisture of 9% to 11%） treatment led to leaf wilting of ordinary cultivars,with reduced plant height,stem diameter and leaf area.Among the traits,the changes of stem diameter and leaf area were highly significant （P〈0.01）.During the reproductive growth （R4） stage,temporary wilting led to significantly lower （P〈0.05） root biomass and branch biomass in ordinary cultivars.When moved to the seed filling （R6） stage,ordinary cultivars wilted without recovery.On the contrary,the droughttolerant cultivars still maintained ability to grow.These results indicated that 48hgerminationrate of soybean seeds could be used as a method in drought resistance identification and screening.They also showed that soybean plants at R6 stage were most sensitive to water stress.