抽雄期干旱胁迫与复水对不同玉米品种生长及产量的影响

【目的】探讨广西不同玉米品种在抽雄期对干旱胁迫及旱后复水的响应,为玉米抗旱机理研究、抗旱品种选育及广西玉米秋播用种选择提供理论依据。【方法】在大棚内采用桶栽法对桂单0810、迪卡008、正大619、琛玉969和桂单901等5个玉米品种在抽雄期进行4、8、12、16和20 d的干旱胁迫处理及相应胁迫时间后的复水处理试验,每个品种均以正常浇水为对照,分别于相应干旱胁迫时间后的第1 d及旱后复水15 d取样,统计次生根数、最长根长和绿叶数,测定各处理根、冠干物质量,计算各指标与对照的比值;成熟期计算单株果穗产量,以产量为基准计算抗旱系数和抗旱指数,并对抗旱系数进行聚类分析。【结果】干旱胁迫下各玉米品种的冠干重、根干重、次生根数、最长根长和绿叶数均比对照下降,且各指标与对照比值随胁迫时间的延长而下降。复水后,各指标的恢复生长量随胁迫时间的增加而减少;除最长根长在干旱胁迫4 d后复水出现超补偿生长外,其他指标均未产生超补偿效应。桂单0810、迪卡008和正大619在干旱胁迫下各指标的降幅均小于琛玉969和桂单901;复水后,前者的恢复能力又高于后者。桂单0810、迪卡008和正大619的抗旱系数和抗旱指数均高于琛玉969和桂单901,通过抗旱系数的聚类分析,可将5个玉米品种分为两大类,桂单0810、迪卡008和正大619归为抗旱性较强的品种,桂单901和琛玉969归为抗旱性较弱的品种。【结论】桂单0810、迪卡008和正大619在抽雄期受干旱胁迫时根、冠生长所受影响较小,且在复水后能够有效地恢复生长,从而保证较高的生物量及产量,可作为广西秋播玉米抗旱品种推广应用。

Effects of drought stress and re-watering on growth and yield of various maize varieties at tasseling stage

Objective]Response of major maize varieties in Guangxi to drought stress and re-watering at tasseling stage was studied to provide reference for drought-resistant mechanism, drought-resistant variety breeding and selection of maize variety for fall sowing. Method]Tub planting experiment in greenhouse was conducted. Five levels of drought stress (4,8,12,16 and 20 d) and re-watering after dought stress were carried on five maize varieties(Guidan 0810,Dika 008, Zhengda 619,Chenyu 969 and Guidan 901). Normal watering for each variety were taken as control. Samples were taken on day 1 of drought stress and day 15 of re-watering. Secondary root number, maximum root length and green leaf number were measured, root dry weight and shoot dry weight in each treatment were detected, and the ratio of each index to control was calculated. At maturation stage, maize ear yield per plant was detected, and drought coefficient and drought resistance index were also calculated based on it. Clustering analysis for drought coefficient was conducted. Result]Shoot dry weight, root dry weight, secondary root number, maximum root length and green leaf number of all the varieties reduced under drought stress. The ratios of the indexes to control decreased as stress time extended. After re-watering,the regrowth amount of all indexes decreased as stress time prolonged. Over compensation effect only occured in maximum root length after re-watering post 4 d drought stress. For other indexes, over compensation effect did not happen. Under drought stress, the drops of the indexes mentioned above of Guidan 0810, Dika 008 and Zhengda 619 were smaller that those of Chenyu 969 and Guidan 901. After re-watering, the regrowth abilities of Guidan 0810, Dika 008 and Zhengda 619 were better than those of Chenyu 969 and Guidan 901. Guidan 0810,Dika 008, and Zhengda 619 performed higher drought coefficient and drought resistance index than Chenyu 969 and Guidan 901. Clustering analysis for drought coefficient classified the five varieties in-to two categories: Guidan 0810,Dika 008,and Zhengda 619 belonged to the varieties with strong drought resistance, and Chenyu 969 and Guidan 901 were the ones with weak drought resistance. Conclusion]Guidan 0810, Dika 008 and Zhengda 619 are less affected by drought stress at tasseling stage for the growth of root and shoot system,and regrow effectively under re-watering after drought stress. These three varieties produce more biomass and high yield. Therefore they are selected as the maize varieties suitable for fall sowing in Guangxi.