白肋烟主要农艺性状的杂种优势及其遗传分析

摘要

选用6个白肋烟品种,采用Griffing II双列杂交模型设计21个基因型处理,利用加-显模型研究分析白肋烟7个主要农艺性状的杂种优势及其遗传特性.结果表明,白肋烟杂种优势在性状间及杂交组合间的表现存在差异,其中株高具有较强的群体平均优势表现,群体平均优势结果与纯显性效应△值的分析结果一致,这表明除叶长外的6个农艺性状表现为正向杂种优势;7个农艺性状均未表现出明显的群体超亲优势,仅株高、节距表现出较小的正向群体超亲优势.7个性状的广义遗传率(HB)在0.18～0.58之间,表明白肋烟主要农艺性状的表型变异受环境及随机误差的影响较大;狭义遗传率(HN)大小顺序为,叶数＞节距＞叶宽＞株高＞茎叶角度＞茎围、叶长.遗传效应方差分量估算结果表明,叶长的遗传变异主要表现显性效应,其余性状的遗传变异由加性效应和显性效应控制,性状叶数、叶宽、节距的基因型加性效应相对较高(P<0.01).%Based on A-D genetic model the heterosis and genetic characteristics of 7 agronomic traits were studied for 6 burley tobacco varieties. 21 genotypes designed by Griffing II diallel cross method. The results showed that the heterosis varied in different agronomic traits and different crossing combinations. Population heterosis over parent mean (Hpm) was in accordance with the △ value of homozygous dominance effects, which indicated that six agronomic traits except the length of middle leaves, including plant height with greater Hpm, stalk circumference, node length, angle of leaf and inflorescence, leaf number and the width of middle leaves had a great positive heterosis. Number of crosses conferred no significant population heterosis over parent better (Hpb) for all seven agronomic traits. Plant height and node length had a little positive Hpb. General heritability in the broad sense (HB) was 0.18~0.58, which implied that phenotypic variations of all seven agronomic traits were mainly controlled by environmental effects and random errors. Leaf number had higher general heritability in the narrow sense (HN), followed by node length, the width of middle leaves, plant height, angle of leaf and inflorescence, stalk circumference and the length of middle leaves, respectively. The unbiased estimate results of genetic random effect variance components showed that only dominance effect controlled the genetic variation of the length of middle leaves, and additive effect and dominance effect did the genetic variation of other agronomic traits. For plants height, the width of middle leaves and node length, their additive effects were significantly different at 0.01 probability levels among these varieties.