灌浆期水分亏缺条件下二、四、六倍体小麦收获指数和水分利用效率的演化

Evolvement of harvest index and water-use efficiency in diploid, tetraploid and hexaploid wheats during grain-filling stage under different water treatments

为揭示不同倍性小麦生长发育、产量性状及水分利用对灌浆期水分亏缺响应的差异,选用二倍体野生一粒小麦(Triticum boeoticum)、栽培一粒小麦(T.monococcum),四倍体野生二粒小麦(T.dicoccoides)、栽培二粒小麦(T.dicoccon),和两个普通六倍体小麦(T.aestivum)品种‘长武134’和‘陕253’6个小麦品种作为供试材料。采用盆栽控水的方法,测定和分析了不同灌浆期土壤水分条件下小麦株高、旗叶叶面积、穗长、根干重、地上生物量、根冠比、千粒重、粒数、产量、收获指数、蒸腾耗水量和水分利用效率等性状的变化。在小麦染色体倍体由二倍体向六倍体进化的过程中,小麦地上生物量、千粒重、穗粒数、产量、收获指数和水分利用效率都显著增加。随着土壤水分从正常→中度亏缺→重度亏缺的减少,收获指数先增大后减小,分别为41.26%、42.48%和38.19%;生物量水分利用效率逐渐增大,分别为2.39、2.43和2.53g·kg–1;产量水分利用效率分别为1.05、1.10和1.04g·kg–1。在灌浆期水分条件是影响收获指数和水分利用效率的关键因素之一。灌浆期的水分亏缺有利于六倍体小麦的收获指数和四倍体的生物量水分利用效率的提高。中度的水分亏缺有利于四倍体和六倍体产量水分利用效率的提高。

Aim Our objective was to understand differences in grain yield and water-use efficiency among wheats of different ploidy. Methods We conducted experiments on six wheat varieties： diploid species （Triticum boeoticum, T. monococcum）, tetraploid species （T. dicoccoides, T. dicoccon） and hexaploid species （T. aestivum Changwu 134 and Shaan 253）. These were treated with different water conditions in the grain-filling stage, and we determined root biomaSD, aboveground biomaSD, grain yield, water consumption for transpiration and water-use efficiency. Important findings There were significant differences in biomaSD, grain yield and water-use efficiency among different wheat varieties with different diploid chromosomes under each water treatment. In the evolution of wheat from diploid to hexaploid, dry weight of root system increased first and then decreased; aboveground biomaSD, 1 000-kernel weight, grain number per spike, grain yield, harvest index and water-use efficiency increased gradually. With the aggravation of drought, harvest index of wheat increased first and then decreased; values of harvest index were 41.26%, 42.28% and 38.19%, respectively. Water-use efficiency for biomaSD gradually increased; values were 2.39, 2,43 and 2.53 g.kg^-1, respectively. Values for water-use efficiency for grain yield were 1.05, 1.10 and 1.04 g.kg^-1, respectively. Therefore, water condition was a key factor influencing harvest index and water-use efficiency during grain-filling stage, and moderate water streSD is helpful to improve water-use efficiency for crops. Water deficit during the grain-filling stage could improve the harvest index of hexaploid wheat as well as biomaSD water-use efficiency of tetraploid wheat, and moderate water deficit may increase yield water-use efficiency of both tetraploid and hexaploid wheat.