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培育抗旱节水小麦品种是保障我国粮食安全的重要途径之一, 优异抗旱种质资源筛选及抗旱性评价方法的研究对于提高抗旱育种效率具有关键作用。本研究采用反复干旱法和田间直接鉴定法分别鉴定323份小麦种质苗期和成株期的抗旱性。结果表明, 随着干旱次数的增加幼苗存活率逐渐下降, 而其变异系数和广义遗传力增加。成株期单株产量抗旱系数与综合抗旱性度量值D显著正相关(R2 = 0.609), 采用综合抗旱性度量值D有利于区分干旱对不同种质产量的影响力。苗期反复干旱存活率(DS)与单株产量的抗旱系数及综合抗旱性度量值D均无显著相关。基于反复干旱存活率筛选得到28份苗期强抗旱种质, 基于单株产量抗旱系数和综合抗旱性度量值D分别得到25和30份成株期强抗旱种质, 其中, 9份种质用2种评价方法均表现强抗旱; 21份种质在苗期和成株期均表现抗旱或强抗旱。本研究为小麦抗旱性评价方法及抗旱亲本的合理选择提供理论指导和信息支撑。
Breeding drought-tolerant wheat varieties is an essential strategy to ensure food security in China. Identification of elite germplasm resources and methodological study of drought tolerance evaluation are the keys to improve drought-tolerance breeding efficiency. The drought tolerance of 323 wheat germplasm resources at seedling and adult stages was evaluated using the methods of repeated drought and direct identification in the field, respectively. With the increase of tested times of drought stress, the seedling survival rates declined, whereas the variation coefficients of seedling survival rates and broad-sense heritabilities increased. The drought tolerance coefficient of yield (DTCGY) showed significantly positive correlation (R2 = 0.609) with drought resistance comprehensive evaluation value (DV), and DV was an effective indicator for distinguishing the vulnerability of yield of different germplasm resources under drought stress. The repeated drought survival rate (DS) at seedling stage had no significant correlation with either DTCGY or DV. Twenty-eight accessions with high drought tolerance at seedling stage were selected based on DS, 25 and 30 accessions with high drought tolerance at adult stage were screened out based on DTCGY and DV, respectively. Among which, nine with high tolerance were detected based on both DTCGY and DV; 21 accessions showed drought tolerance at both seedling and adult stages. This results provide theoretical guidance and basic information for selections of drought-tolerance evaluation methods and elite parents.