Interpreting the genetic basis of silique traits in <i><scp>B</scp>rassica napus</i> using a joint <scp>QTL</scp> network

Abstract

Abstract The objectives of this study were to decipher the genetic determinants of silique length ( SL ), number of seeds per silique ( SN ), thousand seed weight ( TSW ) and to reveal interactions between trait loci. A double haploid population of 181 lines derived from a cross between two Brassica napus genotypes exhibiting contrasting silique traits was evaluated for silique traits under three environmental conditions. Correlation analysis revealed a significant positive correlation between SL and TSW , a weak positive correlation between SL and SN and a negative correlation between SN and TSW . Quantitative trait loci ( QTL ) mapping detected 14 additive QTL and 7 QTL pairs with epistatic interactions. Three additive QTL located on LG A9, A1 and A9 had the greatest effect, explaining 51.49%, 23.54% and 27.15% of the phenotypic variance for SL , SN and TSW , respectively. Additionally, the additive × environment and epistatic × environment interaction effects were negligible, indicating the stability of the genetic effects for these QTL . The results will promote a more comprehensive description of the genetic basis of these silique traits in B . napus .