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20d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.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问的增加而减少;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,可作为广两秋播玉米抗旱品种推广应用.

Effects of Drought Stress and Re-watering on Growth and Yield of Different Maize Varieties at Tasseling Stage

Objective] The aim was to explore the response of different maize varieties in Guangxi to drought stress and re-watering at tasseling stage,so as to provide reference for study on drought resistance mechanism,breeding of drought-resistant varieties and selection of maize varieties for fall sowing.Method] At the tasseling stage,total five degrees of drought stress (4,8,12,16 and 20 d) and corresponding re-watering after drought stress were simulated by a tub planting experiment in greenhouse for five different maize varieties (Guidan 0810,Dika 008,Zhengda 619,Chenyu 969,Guidan 901).Normal watering was set as the control.Sampling was carried out on Day 1 after drought stress and on Day 15 after rewatering,and the secondary root number,maximum root length,green leaf number,root dry weight and shoot dry weight were measured.At the harvest time,the ear yield per plant was measured.With yield as the basis,the drought resistance coefficient and drought resistance index were calculated.Cluster analysis was conducted for drought resistance coefficient.Result] The shoot dry weight,root dry weight,secondary root number,maximum root length and green leaf number of maize in the treatment groups decreased compared with those in the control group.The ratio of each index between the treatment and control groups declined with the extension of drought stress.After re-watering,the re-growth amount of each index all decreased as the stress time prolonged.Post-re-watering over compensation effect occurred in none of the indices except the maximum root length,after 4 days of drought stress.Under drought stress,the reductions of all the indices of Guidan 0810,Dika 008 and Zhengda 619 were smaller than those of Chenyu 969 and Guidan 901.After re-watering,the re-growth abilities of Guidan 0810,Dika 008 and Zhengda 619 were stronger than those of Chenyu 969 and Guidan 901.The drought resistance coefficients and drought resistance indexes of Guidan 0810,Dika 008 and Zhengda 619 were all greater than those of Chenyu 969 and Guidan 901.The results of drought resistance coefficient cluster analysis showed that the five maize varieties were classified into two groups:Guidan 0810,Dika 008 and Zhengda 619 had strong drought resistance,while Guidan 901 and Chenyu 969 had weak drought resistance.Conclusion] The root and shoot growth of Guidan 0810,Dika 008 and Zhengda 619 was slightly affected by drought stress during the tasseling period,and they restored the growth rapidly after re-watering,thus ensuring high biomass and yield.Therefore,Guidan 0810,Dika 008 and Zhengda 619 can be promoted as drought-resistant autumn maize varieties in Guangxi.