家蚕茧质性状的QTL定位研究

采用QTLMapper 2．0 QTL作图软件，对F2群体的家蚕全茧量、茧层量、茧层率和蛹体重等性状进行了QTL定位分析，分别检测出7个、6个、2个、8个有显著效应分量的QTLs，分布于7个、5个、2个、7个不同的连锁群。控制全茧量、茧层量的QTLs一般存在复杂的上位性效应。对全茧量性状，有3对QTLs存在显著的加加上位性效应，其中1对还存在加显、显显互作；共有3个QTLs存在显著的显性效应，1个存在显著的加性效应。对茧层量QTLs，发现1对QTLs存在极显著的各项遗传效应，包括上位性效应；1对QTLs被检测到显著的显显互作，1个QTL具有显著的显性效应，并与另一个QTL存在显著的加加互作。茧层率、蛹体重主要受加性或显性的QTLs作用，没有发现茧层率QTLs的上位性效应，蛹体重的有效QTL大都呈现显著的负向显性效应，只有一对QTLs存在显著的加加上位性效应。第2、3、4、11、13、24、34、37、40连锁群是两个或多个性状QTLs分布的共同连锁群。全茧量和茧层量存在共同的QTL或染色体区域，育种上可通过适当选配，利用基因的互作效应，同步改良这两个性状。

Study on Location of QTLs Controlling Cocoon Traits in Silkworm

On the basis of the molecular linkage map,mapmaker software QTLMapper 2.0 was used to analyze the QTLs effect of the whole cocoon weight,cocoon shell weight,ratio of cocoon shell and pupa weight of domestic silkworm,For these four cocoon quantitative traits.7,6,2 and 8 effective QTLs were detected and mapped to 7,5,2 and 7 linkage groups,respectively,Complicated epistatic effects were found involved in the genetic variation of the whole cocoon weight and cocoon shell weight.For the whole cocoon weight,there were three pairs of QTLs with significant additive by additive interactions,in which,one pair had significant additive by dominance and dominance by dominance interactions.Wheseas significant dominance were detected for three QTLs and significant additive effects one QTL had.For the cocoon shell weight,significant genetic effects,including epistatic effects were found for one pair of QTLs,significant dominance by dominance interaction for another pair of QTLs;one QTL had significant dominance and another QTL had additive by additive interaction.The ratio of cocoon shell and the pupa weight were controlled mainly by additive or dominance effects.No interaction between QTL was found for the ratio of cocoon.Most QTLs,associated with the pupa weight,had negative dominance effects.Only significant additive by additive interaction was found between one pair of QTLs.The 2nd,3rd,4th,11th,13th,24th,34th,37th,and 40th linkage groups are the common chromosomal regions harboring QTLs of two or more cocoon quantitative traits.There are identical QTL or chromosomal region for the whole cocoon weight and cocoon shell weight,indicating they can be simultaneously improved by utilizing epistatic effects in breeding.