Additive effects and epistasis effects of QTL for plant height and its components using single segment substitution lines (SSSLs) in rice.

Plant height is a typical quantitative trait that is liable to be influenced by genetic backgrounds and environments.As a novel research material,single segment substitution lines and double segment pyramiding lines in rice will make QTL identifica-tion and epistasis analysis more accurate because of diminishing the interference of genetic backgrounds among plants.In this study,Detection of QTLs controlling plant height and its components and analysis of epistasis effects were done with 16 secon-dary single segment substitution lines and 15 double segment pyramiding lines derived from crossing of primary SSSLs by ran-domized blocks design.The main results showed that 11 QTLs were detected and distributed on chromosomes 4,6,and 10,of which three QTLs controlling plant height,one QTL coffering length of the first inernode from the top,two QTLs harboring length of the second internode from the top,two QTLs for length of the third internode from the top and three QTL controlling length of the fourth internode from the top were included.Twenty-three digenic interactions were detected for plant height and its components,of which 7 interactions occurred between two loci both not having main effects on the traits,and 16 interactions each involved one locus having a main effect at the single-locus level and another locus that did not show significant effect at the sin-gle-locus level.The results indicated that both additive effects of QTL and epistasis effects between QTLs were important genetic components.Efficiency of QTLs identification and epistasis effects analysis between QTLs could be improved using secondary single segment substitution lines and double segment pyramiding lines derived from crossing of primary single segment substitu-tion lines.