烤烟若干农艺性状的杂种优势及其遗传分析

本文用5个烤烟品种按Griffing模型Ⅱ配组,分析了烤烟8个农艺性状的杂种优势表现及其性状遗传规律.研究表明,烤烟杂种优势表现因性状和杂交组合的不同而不同,节距、株高、叶长、叶宽具较强的杂种优势,茎围、叶数的优势较弱;开花至现蕾天数没有明显优势,但当双亲差距较大时F1有推迟现蕾现象;F1青枯病病指因组合不同存在优势大小和方向的明显差异,总体表现略高于中亲值而偏向于感病亲本,但优势较小.采用MINQUE法对8个性状的遗传分析表明,移栽至现蕾天数广义遗传率(HB)最高,其次为叶数、节距、株高和叶宽,叶长和青枯病病指HB较小,茎围则主要受环境影响;遗传方差组成分解结果,青枯病病指为简单的加性遗传,其余性状的遗传中加性和显性的作用也不同,狭义遗传率(HN)大小顺序为移栽至现蕾天数＞叶数＞节距、叶宽、青枯病病指＞株高＞叶长.5个烤烟亲本品种在不同性状上有显著不同的加性效应,表明它们在杂交育种中具有不同的利用价值,纯合显性效应的分析表明烤烟性状杂种优势多数表现正向优势.

The analysis of heterosis and inheritance of some agronomic characters of flue-cured tobacco

Five flue-cured tobacco varieties were used to make crosses followeing the Griffing diallel-cross-test method I . Ten crosses and five parents were grown in 3 replications of a randomized block design for estimating heterosis and genetics of 8 agronomic characters including plant height, node length, stalk circumference, leaf number, leaf length, leaf size, days to emerging of flower bud, resistance to granuville wilt disease in 1999. Results showed that, the heterosis was varied in different characters and different crosses. Numbers of crosses had a great standard heterosis of node length, plant height, leaf length, leaf size, whereas had little standard heterosis of stalk circumference and leaf number. Heterosis of days to emerging of flower bud in numbers of crosses were not obvious, but the hybrid had a later time of emerging of flower bud than the mean of two parents when the distance between two parents was farther. The hybrid resistance to granuville wilt disease was varied with the crosses, but the mean disease indexes of the hybrids were a little higher than the mean of two parents, and close to the parent of a higher disease index. Eight characters were analyzed genetically by the MINQUE method and result showed that days to emerging of flower bud had the highest broad heritability (HB), leaf number, node length, plant height and leaf size, both leaf length and granuville wilt disease index had a lower board heritability while stalk circumference had a insignificant heritability. The genetic variance of seven characters but stalk circumference was decomposed, the result showed that resistance to granuville wilt disease was simply controlled by additive effects, other six characters were concurrently controlled by additive and dominant effects, but the magnitude of additive and dominant effect differed with characters. The order of the characters by narrow heritability (HN) was days to emerging of flower bud>leaf number > node length > leaf size > resistance to granuville wilt disease > plant height > leaf length. Five varieties had different additive effect in different characters, which indicated their different value in cross breeding. By analysis of homo-additive-effect, it also revealed that most agronomic characters had positive heterosis in flue-cured tobacco hybrid.