山西省小麦苗期根系性状及抗旱特性分析

小麦苗期根系形态是成株期根系分布的基础,与抗逆和产量密切相关,全面认识苗期根系及抗旱特性,对于抗旱优异种质的利用和早期筛选具有重要意义。采用239份山西省小麦品种(系)在土培条件下,研究了苗期根系性状及对水分胁迫的响应。结果表明,正常生长下山西小麦苗期根系性状多样性丰富,地方种变异最大;不同年代品种中,除最大根长随年代略下降外,其他性状均呈先升后降的趋势;不同根系性状对水分胁迫响应存在差异,总根长对水分最敏感,其次为根表面积、根体积和根生物量,最大根长和平均根数不敏感。苗期根系综合抗旱能力随年代呈先降后升的趋势,地方种和20世纪70年代品种多为中抗,80和90年代的品种抗旱性较低,2000年以后审定品种的抗性较高,其中旱地品种抗性最好。苗期根系抗旱特性与产量性状相关分析发现,最大根长、总根长、根体积和根生物量与雨养条件下的千粒重和产量显著正相关,最大根长和根生物量与成株期抗旱性也显著正相关。因此苗期最大根长和根生物量可作为半干旱地区旱地育种过程中抗旱性和产量的早期筛选指标。

Seedling root characteristics and drought resistance of wheat in Shanxi province

Wheat root morphology at the seedling stage is the basis of root distribution at the adult stage.It is closely related to stress resistance and yield.A comprehensive understanding of the root system characteristics at seedling stage and drought resistance is of great significance for the excellent germplasm utilization and early screening of drought resistance.Using 239 wheat varieties(lines)from Shanxi province,the root traits at seedling stage and their response to water stress were evaluated.The results showed that under normal growth,Shanxi wheat had a great variation in root traits at seedling stage,with the greatest variation in landraces.The maximum root length(MRL)tended to decrease slightly with the years,while other root traits were first increased and then decreased.There were differences among the root traits in response to water stress.The total root length(TRL)is the most sensitive to water,followed by root surface area(RSA),root volume(RV)and root biomass.The maximum root length(MRL)and the average number of roots(RN)were insensitive.The drought resistance of seedling roots showed a trend of decreasing first and then increasing with the years.Landraces and varieties released from 1970 to 1979 had moderately resistance to water stress,varieties released from 1980 to 1999 had lower drought resistance,and varieties released after 2000 had the better resistance,of which the dryland varieties were the best resistance.Correlation analysis of the seedling root characteristics and yield related traits suggested that the maximum root length,total root length,root volume and root biomass were significantly positively correlated with 1000-kernel weight and yield under rain-fed conditions,and the maximum root length and root biomass were also significantly positively correlated with adult plant drought resistance.The present study suggests that the maximum root length and root biomass at the seedling stage can be used as early generation selection parameters for drought resistance and yield in dryland breeding in semi-arid areas.