不同水分条件下小麦灌浆期功能叶片的遗传特性

Genetic characteristics of wheat functional leaves at filling stage under different water regimes

2005—2007年,以小麦DH群体(旱选10号×鲁麦14)的150个株系及其亲本为材料,研究在灌溉和雨养两种水分条件下,小麦灌浆中期上部3片功能叶的长、宽及基角遗传基础及其与产量性状的关系.结果表明:与灌溉条件下的性状相比,雨养条件下小麦灌浆中期上部3片功能叶的长和宽均显著降低,而叶基角表现复杂.两种水分条件下,DH群体所有性状均表现超亲分离,变异系数在5.1%～45.9%,性状平均值多数介于双亲之间;旗叶基角遗传力均最高(91%和97%),而倒3叶基角均最低(23%和31%);控制旗叶基角的基因数目均最少,灌溉和雨养条件下均分别为4对和2对,控制倒3叶基角的基因数目2007年均最多,分别为21和25对;两种水分条件下控制上部3叶基角,以及灌溉条件下控制倒3叶长的多基因间存在互补作用.3片功能叶长、宽与穗粒数、穗粒重之间多数为显著正相关,倒3叶长、旗叶基角、倒2叶基角与千粒重、单株产量呈显著正相关,但相关系数均较小(<0.481).因此,可以在育种早代对上部3叶长、宽进行比较严格的选择,而对叶基角的选择应在育种高代进行;在小麦上部3片功能叶生长的关键时期保证适宜的土壤水分,能够促进叶片正常生长,提高产量.

Taking one hundred and fifty doubled haploid （DH） lines of winter wheat cultivars Hanxuan 10×Lumai 14 as well as their parents as test materials,the genetic bases of top three leaves length,breadth,and angle at mid-filling stage,and their correlations with yield traits were studied under two water regimes rainfed （drought stress,DS） and well-irrigation （WI） in 2005-2007. Under DS,the leaf length and width of DH lines and their parents were significantly lower than those under WI,whereas the leaf angle had a miscellaneous variation. Under the two water regimes,all the test traits of DH lines had a transgressive segregation,with the variation coefficients ranged from 5.1% to 45.9%. The heritability and gene numbers for the given traits showed great differences. Under WI and DS,the heritability of flag leaf angle （FLA） was the highest （91% and 97%,respectively）,and that of the third leaf angle （TLA） was the lowest （23% and 31%,respectively）. However,the gene number for FLA （4 and 2 under WI and DS,respectively） was the least,and that of TLA （21 and 25,respectively） in 2007 was the most. Interactive effects were observed among the genes controlling FLA,second leaf angle （SLA）,and TLA under WI and DS,and controlling third leaf length （TLL） under WI. The grain number per spike and the grain weight per spike were positively correlated with the length and width of top three leaves,and the thousand-grain weight and the yield per plant were significantly correlated with TLL,FLA,and SLA,but all correlation coefficients were smaller （〈0.481）. It was suggested that the selection of top three leaves length and width should be carried out in the early generations of breeding procedure,while that of leaf angles should be carried out in advanced generations. An appropriate soil moisture regime retained in the critical growth period of the leaves would promote their growth and contribute to the grain yield.