玉米穗轴的颜色变化,是偶然还是与农艺性状存在关联?--以历年国审普通品种为例

Is cob color variation in maize accidental or incidental to any agronomic traits?—An example of nationally approved common hybrids over the years

玉米穗轴颜色在温带种质及商业化杂交品种中受到强烈的人工选择。为了明确我国不同区域玉米穗轴颜色选择的偏向性,探索轴色与多种农艺性状间的关联,本文以1992—2020年国审普通玉米品种为例,对品种轴色、审定区域及多项农艺性状进行了比较分析。在统计到的1604个品种中,红轴品种占比从1992年的50%逐渐提高至2020年的80%以上。其中,北方春玉米区、黄淮海夏玉米区和西北玉米区的红轴品种比例随年份更替提升速度高于西南和南方玉米区。对比分析红、白轴品种在株型、果穗和籽粒特性等方面的差异发现,近15~20年间的红轴品种平均穗长和穗行数均显著高于白轴。随年代更替,红轴品种的籽粒平均粗淀粉含量升高趋势快于白轴,但其平均粗脂肪含量下降明显,并且红轴品种平均粗蛋白含量和赖氨酸含量表现弱于白轴。因此,针对红色穗轴的强烈人工选择可能主要与玉米单株产量潜力的挖掘有关。但红轴品种在非生物逆境抗性和籽粒品质方面的表现需要进一步探讨。

Maize cob color has undergone powerful artificial selection in temperate germplasm and commercial hybrids.To clar-ify the selection bias of cob color in maize in different regions,and to explore the association of cob color with various agronomic traits,we used the public data of nationally approved maize hybrids from 1992 to 2020 to analyze the released regions and multi-ple agronomic traits of hybrids with different cob colors(red or white).Among the 1604 hybrids counted,the proportion of red cob hybrids has gradually increased from 50%in 1992 to more than 80%in 2020.The proportion of red cobs in the Northern spring maize region,Huanghuaihai summer maize region,and Northwestern maize region increased faster than that in the South-western and Southern maize regions.The average ear length and kernel row number of the red cob hybrids and white axis varie-ties were significantly higher than those of the whites in the recent 15–20 years.The average crude starch content of the reds in-creased significantly over the years,while the average crude fat content decreased significantly.The average crude protein and lysine content of the reds were weaker than that of the white axis varieties.Therefore,we speculate that the strong artificial selec-tion for red cob may be mainly related to the pursuit of maize yield potential per plant.However,the performance of red cob hy-brids in abiotic stress and grain protein quality deserves further exploration.