烤烟化学成分的遗传效应分析

Analysis of Genetic Effects of Chemical Components in Flue-cured Tobacco

为科学合理地进行烤烟育种中的亲本筛选与组合配制,选育出化学成分协调的烤烟新品种(系),利用6个烤烟品种(K326、6388、RG17、K8、净叶黄和南江3号)按Griffing方法(Ⅱ)完全双列杂交配制出30个杂交组合,并对烟叶的烟碱、总氮、总糖、钾、氯、氮碱比、糖碱比和钾氯比等8个化学成分指标进行了初步遗传效应分析。结果表明,组合间的所有性状差异均达到了极显著水平,亲本间的一般配合力(GCA)和组合间的特殊配合力(SCA)均存在极显著差异,而且除氮碱比指标外的其他化学成分指标GCA方差均大于SCA方差,表明对本试验中烤烟绝大部分化学成分指标性状而言,亲本选择比组合配制更重要。对于GCA效应,RG17和南江3号品种分别具有提高钾和钾氯比的潜力,而6388则具有降低氯含量的潜力。基于烤烟化学品质目标分析SCA效应,30个组合中以K326×南江3号、净叶黄×南江3号和K8×净叶黄3个组合表现最佳,其次是K326×净叶黄和K8×RG17两个组合。化学成分指标性状间的遗传力存在较大差异,狭义遗传力以钾最大(33.82%),总糖最小(1.37%),而广义遗传力以氯和钾最大,分别为51.84%和50.04%,总糖最小(15.08%),只有钾的狭义遗传力占广义遗传力的比例超过了50%,说明钾的遗传以加性效应为主,这有利于培育高钾品种,且适宜进行早代选择,对于其他化学成分指标性状,在性状基本稳定的时期进行株系选择比较适宜。

In order to breed new flue-cured tobacco lines of harmonious chemical composition via scientific and rational parent selection and combination collocation, thirty complete diallel cross combinations were prepared from six flue-cured tobacco varieties with Griffing method （Ⅲ）. The genetic effects of eight chemical component indexes （the contents of nicotine, total nitrogen, total sugar, potassium, chlorine and the ratios of total nitrogen/nicotine, total sugar/nicotine, potassium/chlorine） in tobacco leaves were preliminarily analyzed. The results showed that the said chemical indexes differed extremely significantly between combinations, the general combining ability （GCA） between parents and the specific combining ability （SCA） between combinations exhibited extremely significantly differences as well. Moreover, the variance of GCA was greater than that of SCA for all the indexes except for the ratio of total nitrogen/nicotine. It indicated that for most of the chemical indexes investigated in this experiment, parent selection was more important than combination collocation. For GCA effect, cv. RG17 possessed a potential in increasing potassium content and cv. Nanjiang No.3 might increase potassium/chlorine ratio; 6388 lines presented a potential in decreasing chlorine content. Analyzing SCA effect from the point of chemical quality, the combination of K326 × Nanjiang No.3, Jingyehuang × Nanjiang No.3 and K8 × Jingyehuang were the best, followed by K326 × Jingyehuang and K8 × RG17. There existed obvious heritability differences between the traits of chemical indexes. Potassium content and total sugar content possessed the highest and the lowest special heritability of 33.82% and 1.37%, respectively. The general heritability of chlorine content （51.84%） and potassium content （50.04%） was the highest, while that of total sugar content （15.08%） was the lowest. Only the special heritability of potassium content accounted for over 50% of general heritability, it indicated that the heritability of potassium content mainly was additive effect, which facilitated to the breeding tobacco cultivars of high-potassium content and was suitable to line selection at earlier generation. For the traits of other chemical indexes, it would be preferable to carry out line selection while the trait became stable.