Walker R D, White D G
Department of Crop Sciences, University of Illinois, Urbana 61801.
Plant Dis. 2001 Mar;85(3):322-327. doi: 10.1094/PDIS.2001.85.3.322.
This study determined the types and magnitude of gene action, estimated heritabilities, and predicted gain from selection for resistance to Aspergillus ear rot and aflatoxin production in the cross of resistant corn inbred CI2 to susceptible inbred B73 in 1998 and 1999. The warm, dry summer of 1998 favored aflatoxin production, whereas the conditions of 1999 did not. Resistance to ear rot was mainly controlled by additive gene action. Aflatoxin values were analyzed by individual years (environments) because of the highly significant generation × environment interaction. Resistance to aflatoxin production was mainly controlled by epistasis in 1998 and by additive gene action in 1999. Heritabilities for ear rot and aflatoxin production were higher in the F generation than in the BCP-selfed generation. In 1998, Spearman's correlation coefficients between Aspergillus ear rot ratings and aflatoxin values for the F and the BCP-selfed families were not significant (P > 0.05). In 1999, both were highly significant (P < 0.01), but low at 0.41 and 0.17 for the F and BCP-selfed generations, respectively. We found that CI2 is not an acceptable source of resistance due to lower heritabilities and disease resistance compared to other sources of resistance.
本研究确定了基因作用的类型和程度，估计了遗传力，并预测了1998年和1999年抗性玉米自交系CI2与感病自交系B73杂交后代对曲霉菌穗腐病和黄曲霉毒素产生抗性的选择增益。1998年温暖干燥的夏季有利于黄曲霉毒素的产生，而1999年的情况则不然。对穗腐病的抗性主要由加性基因作用控制。由于世代×环境互作极显著，因此对黄曲霉毒素值按年份（环境）进行分析。1998年，对黄曲霉毒素产生的抗性主要由上位性控制，1999年则由加性基因作用控制。穗腐病和黄曲霉毒素产生的遗传力在F代中高于回交亲本自交世代。1998年，F代和回交亲本自交家系的曲霉菌穗腐病评级与黄曲霉毒素值之间的斯皮尔曼相关系数不显著（P>0.05）。1999年，两者均极显著（P<0.01），但F代和回交亲本自交世代分别较低，为0.41和0.17。我们发现，与其他抗性来源相比，由于CI2的遗传力和抗病性较低，它不是一个可接受的抗性来源。
