玉米籽粒中花色苷和黑色素含量的QTL分析

花色苷和黑色素是黑玉米籽粒中重要而有益的化学成分，深入开展其QTL定位研究，对于色素相关基因的克隆与转化和分子标记辅助育种，具有重要的理论意义和应用价值。本文利用一个黑玉米自交系SDM为共同父本，分别与白玉米自交系木6和黄玉米自交系Mo17杂交，构建2个相关F_2:3群体(分别缩写为WD和YD)，对玉米籽粒中花色苷含量(ACK)和黑色素含量(MCK)进行QTL分析。结果表明，黑玉米SDM籽粒中的花色苷和黑色素含量均极显著高于木6和Mo17，2种色素含量间呈极显著正相关。2个群体中共检测到17个色素相关的QTL，其中与花色苷含量相关的QTL在2个群体中各4个，分布在第4、第6、第7和第10染色体上，与黑色素含量相关的QTL在WD和YD群体中分别为4个和5个，分布在第1、第2、第6、第7和第10染色体上。2个群体检测到QTL的数量、分布和对表型的贡献率均高度一致，而且解释花色苷含量和黑色素含量变异大的QTL在2个群体中均有成簇分布的现象，主要表现在bin 6.04处的标记区间umc1796~mmc2006内和bin 10.04处的标记区间umc2043~bnlg1028内，分别解释表型变异的12.7%~21.3%和8.6%~21.3%。它们可能是一因多效的同一QTL或者是在该区段内紧密连锁的不同QTL。上位性分析表明，2个群体中检测到的上位性QTL的数量、位置和对表型的贡献率差别均较大，WD群体的上位性效应明显大于YD群体，说明上位性效应对遗传背景更加敏感，需要进一步深入研究贡献率大的上位性QTL及其利用。

QTL Mapping for Anthocyanin and Melanin Contents in Maize Kernel

Anthocyanin and melanin are important and beneficial chemical components in black maize kernel.It is important to comprehensively study the QTL mapping for anthocyanin and melanin,cloning and transfer of pigmentation-related genes and marker assistant breeding.In this study,two related F2:3 populations derived from crosses of Mu6×SDM(WD) and Mo17×SDM(YD) were used to identify QTLs for anthocyanin and melanin contents in maize kernels.The results showed that the phenotype and QTL identification of two populations were highly consistent.The anthocynian and melanin contents of SDM were signifi-cantly higher than those of Mu 6 and Mo17.The positive correlation between the two pigment contents in kernel was highly sig-nificant.A total of seventeen QTLs were identified,including eight QTLs for ACK and nine QTLs for MCK.For ACK,four QTLs were both detected in two populations,which were distributed on chromosomes 4,6,7,and 10.For MCK,four and five QTLs were identified in WD and YD populations,respectively,which were distributed on chromosomes 1,2,6,7,and 10.The number,distribution and effects of QTLs in two populations were highly consistent,and the major QTLs of ACK and MCK in two popula-tions were both clustered,which were detected in the intervals of umc1796-mmc2006(bin 6.04) and umc2043-bnlg1028(bins 10.04) and explained 12.7-21.3% and 8.6-21.3% of phenotype variation,respectively.These QTLs which were stable in different genetic backgrounds might be closely linked to each other,or a same pleiotropic QTL which could be used in fine mapping and cloning of pigmentation-related genes in maize.The result of epistasic analysis indicated that the number,position and effects of epistatic QTLs between two populations were much different,and epistasic effects were more obvious for WD than for YD.Some epistatic QTL pairs explaining more than 10% variation of phenotype play an important role in pigment production and should be further studied.