Study on early identification method of drought tolerance of mungbean cultivars | 绿豆品种抗旱性早期鉴定方法研究

Chinese. 探讨早期鉴定绿豆品种抗旱性的简易方法，为绿豆抗旱育种提供借鉴。依据种子吸水后24 h的发芽率对25个绿豆种质材料进行抗旱性分级，从中筛选出4个抗旱品种和4个普通品种，采用盆栽控水试验，研究水分胁迫处理（土壤含水量控制在9%~11%）对绿豆生长指标及生物量的影响，根据绿豆植株的抗旱性表现来验证依据种子24 h发芽率划分的抗旱等级。不同绿豆品种间种子24 h发芽率存在明显差异。种子吸水量与抗旱等级不相关，幼苗侧根数、主根长度和根系干质量与抗旱等级呈显著（P0.05）或极显著（P0.01）正相关关系。对萌发后幼苗正常供水24 h后，随即停水24 h，重复5次，抗旱品种的存活率显著高于普通品种。在营养生长期，停水后普通品种叶片首先发生萎蔫，且随着停水时间的延长，普通品种萎蔫叶片数均高于抗旱品种；复水后，抗旱品种叶片的恢复能力强于普通品种。水分胁迫条件下，绿豆抗旱品种的株高、茎直径和叶片面积均显著高于普通品种，其中抗旱品种与普通品种的茎直径和叶片面积差异达到极显著水平。在结荚期，抗旱品种的根、叶片、荚生物量显著高于普通品种。鼓粒期，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。测定种子24 h发芽率可作为早期绿豆品种抗旱性鉴定和筛选的方法。

English. A method for identifying drought-tolerance of mungbean varieties was discussed in order to provide a theoretical basis for drought-tolerance breeding of mungbean. A simple method of germination rate at 24 h-after-water-absorption was used and verified to investigate mungbean drought-tolerance. The drought-tolerance of 25 mungbean germplasms was graded according to seed germination rate at the germination stage, and then in pot water-control trails at vegetative growth stage and reproductive growth stage. It indicated that there were significant differences in drought-tolerance among mungbean materials. Water absorption made no difference to drought-tolerance. However, germination rate of 24 h-after-water-absorption and drought-tolerance were closely correlated. Seedling branch root number, main root length and root dry weight had significant (P0.05) or highly significant positive correlation (P0.01) with drought-tolerance. Under repeated stress of supplying water for 24 h after germination and then no water for 24 h, the survival rate of drought-tolerant cultivars was higher than that of ordinary ones. At the vegetative growth stage, 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. During the reproductive growth stage, temporary wilting induced significantly lower root biomass and branch biomass in ordinary cultivars. When moved to the seed filling stage, ordinary cultivars wilted without recovery. On the contrary, the drought-tolerant cultivars still maintained ability to grow. These results indicated that 24 h-germination-rate of mungbean seeds could be used as a method in drought resistance identification and screening.