黄土高原不同年代旱地冬小麦品种产量及光合特性对密度的响应

Responses of Yield and Photosynthesis Characteristics to Density of Dryland Winter Wheat Cultivated from Different Decades on the Loess Plateau

为研究旱地冬小麦品种更替过程中产量与光合特征对群体大小的响应,选择1940-2004年先后培育的7个冬小麦品种,于2011-2012年在陕西长武农业生态试验站进行田间试验,并设置3个播种密度(100、250、350粒/m^2)。在所有密度处理中,子粒产量均随着品种的更替而呈线性增长,年均遗传增益在0.65%到1.29%之间。1980年后培育的小麦品种的产量对于播种密度更不敏感,具备更好的群体调节能力。现代品种收获指数和千粒重的提高与其产量的提升呈显著正相关。品种更替过程中花期旗叶净光合速率和叶面积指数持续增长,并提高千粒重,最终增加产量。花期时冠层下可见天空比随着品种更替呈显著下降趋势。在黄土高原的冬小麦育种工作中,应将耐密性、大库容、高光效的理想株型作为重要的筛选指标。

An experiment was conducted to verify how the grain yield and associated photosynthesis characteristics of wheat responded to density with cultivar replacement. Seven wheat cultivars released from 1940 to 2004 were once widely grown on the Loess Plateau during the 2011-2012 growing season at the Changwu experimental station in China,using three densities（100,250,and 350 seeds/m2）. The grain yield increased linearly with cultivar development at all densities,with annual genetic gains ranged from 0.65% to 1.29%. The cultivars released after the 1980 s were less sensitive to density and had better population regulation. The improvement in the harvest index and thousand-grain weight of the modern cultivars were significantly and positively correlated with the grain yield. The photosynthetic rate of the flag leaf and the leaf area index at anthesis stage consistently increased with cultivar replacement,contributing more to the thousand-grain weight and resulted to the increase of grain yield. One reason to adaptation of modern cultivars for modern cultivation was their lower sensitivity to density. Thus,larger sink for the grains and the optimization of plant types for light interception should be given greater consideration in dryland wheat breeding on the Loess Plateau.