甘蓝型油菜芥酸含量的三重测交分析

Triple Test Cross Analysis of Erucic Acid Content in Brassica napus L

本文用扩展三重测交设计研究了甘蓝型油菜芥酸及其他脂肪酸含量的遗传。结果表明,芥酸的上位性效应不显著,主要受加性效应控制,显性作用较小。显性方向为正,一级统计量分析不显著,二级统计量分析达显著水平。方差分量 D,H 和 F 的估值分别为358.15—362.22,8.74—18.00和51.77—53.26。平均显性度为0.1553—0.2242,优势比为0.0051—0.1156,基因数目的估值平均为2.02±0.0298。两个基因座位的加性效应基本上相等,平均约为13.50%。廿碳烯酸、十八碳酸(油酸、亚油酸和亚麻酸之和)和棕榈酸存在极显著的上位性效应,廿碳烯酸和十八碳酸符合六参模型,前者[i],[j],[l]互作均显著,后者[l]互作不显著。棕榈酸不符合六参模型。

The genetic parameters of erucic acid were estimated by the augmented triple testcross(aTTC)analysis developed by the senior author(1988).The results indicated that theerucic acid content had no significant epistasis and was governed by genes acting in anadditive manner.The dominance effects were less important compared with the additiveeffects,and insignificant in the analysis of first degree of statistics and significant in theanalysis of second degree statistics.The direction of dominance was positive,i.e.thegene E for erucic acid was slightly dominant to e for the absence of erucic acid.Theaverage degree of dominance (H/D)^(1/2) ranged from 0.1553 to 0.2242,potence ratio[h]/[d] from 0.0051 to 0.1156,and the degree of dominance of each locus was near-ly equal.The estimates of D,H and F were 358.15—362.22,8.74—18.00 and51.77—53.26,respectively.The estimates of gene number ranged from 1.91 to 2.11which were almost equal to the value 2 obtained from Mendlian genetics.Theadditive effects of two loci were approximately equal,and the average effect of additiveof each allele was about 13.5%.Eicosenoic and palmitic acids,the acids with 18 car-bons(the sum of oleic,linoleic and linolenic acids)had highly significant epistasis.Palmitic acid did not fit the digenic interaction model but the others did.