华北平原夏玉米氮利用效率的遗传参数估计

Estimation of quantitative genetic parameters for improving nitrogen use efficiency in North China summer maize

为研究玉米品种氮利用效率相关性状的遗传参数,本试验选择20个具不同氮利用效率的单交种在华北平原的2个地点同期进行试验,氮肥处理设高氮(施氮,折合纯氮225 kg/hm2)和低氮(不施氮,其地块经过连续2年耕种使氮素耗竭)2个水平。试验结果表明,供试品种在低氮水平下的平均产量比高氮降低了22.6%,从8.45 t/hm2降低到6.45 t/hm2,穗粒数减少幅度较大为17.12%;而千粒重、出籽率、干物质含量、株穗率、籽粒含油率、籽粒蛋白质和淀粉含量在2个氮水平下的平均表现相近。2个试验点的联合方差分析表明,以上大部分籽粒性状的遗传方差在2个氮水平下均达到显著水平;所有性状的基因型×氮的互作方差都不显著。在2种氮水平下,籽粒淀粉含量与籽粒含油率及籽粒蛋白质含量间都表现出显著负相关,籽粒含油率与蛋白质含量表现出较弱的正相关。高氮和低氮水平下的产量表型相关系数为0.759,表明可以在高氮水平进行氮高效品种的筛选。

To estimate the quantitative genetic parameters of nitrogen use efficiency, twenty maize single-cross hybrids with varying nitrogen use efficiency were tested at two locations in the North China Plain. At both locations, the hybrids were grown under high （HN, 225 kg/hm^2 N） and low （LN） N levels. And no N fertilization on the LN field have lasted two years. For LN compared to HN, average grain yield was reduced from 8.45 to 6.54 t/hm^2 , which was mainly due to a reduced number of kernels per ear by 17.12%. Average values of thousand kernel weight, grain dry matter content, grain content, number of ears per plant, grain oil content, grain protein content and grain starch content were similar at both nitrogen levels. In the combined analyses across locations, genotypic variances were significant for most traits at both nitrogen levels. But the genotype x nitrogen variance interactions were not significant for all traits. Under both nitrogen levels, grain starch content and oil content showed close negative correlations, whereas grain oil content and grain protein content showed an intermediate positive correlation. The phenotypic correlation for grain yield between HN and LN levels was 0.759. This indicated that selection for variety with high nitrogen use efficiency could be conducted under HN condition.