甜荞株高和茎粗的遗传分析

Genetic Analysis of Plant Height and Stem Diameter in Common Buckwheat

甜荞极易倒伏,而株高和茎粗是影响甜荞倒伏的重要性状。以高秆健壮品种酉荞2号和矮秆纤细品种乌克兰大粒荞为亲本配制正、反交组合,P_1、P_2、F_1、B_1、B_2和F_2群体株高和茎粗的遗传分析表明,株高和茎粗的最适遗传模型均为2对加性-显性-上位性主基因+加性-显性多基因模型。株高正交组合中2对主基因加性效应均为-1.39,显性效应分别为-6.59和-7.91,B_1、B_2和F_2群体主基因遗传率分别是45.73%、63.49%和81.12%,多基因遗传率分别是27.41%、0.95%和0;反交组合中2对主基因加性效应值均为-1.63,显性效应分别为-7.03和-4.19,B_1、B_2和F_2群体中主基因遗传率是41.51%、66.18%和81.81%,多基因遗传率分别是11.19%、0和0。茎粗正交组合中2对主基因加性效应均为0.03,显性效应分别为-0.50和-0.08,B_1、B_2和F_2群体中主基因遗传率分别是37.26%、48.80%和72.10%,多基因遗传率分别是11.18%、0和0;反交组合中2对主基因加性效应均为-0.15,显性效应分别为-0.30和-0.16,B_1、B_2和F_2群体中主基因遗传率是76.22%、47.12%和82.51%,多基因遗传率分别为0、14.53%和0。可见,株高的主基因+多基因遗传率在80%以上,可在低世代进行选择;茎粗的主基因+多基因遗传率在80%以下,采取合理的栽培措施可以提高荞麦抗倒伏能力。

Common buckwheat （Fagopyrum esculentum M.） is susceptible to lodging, and plant height and stem diameter are recognized as important traits for lodging resistance. In this study, we developed the Pl, P2, Fl, F2, Bl, and B2 populations from the reciprocal crosses between Youqiao 2 （YQ2, lodging-resistance） and Ukraine daliqiao （UD, lodging-susceptible） and analyzed the genetic effects of plant height and stem diameter. The heredity of both traits optimally fitted to the genetic model for two major genes with additive-dominance-epistatic effects plus polygenes with additive-dominance effects. For plant height in the orthogo-nal combination, additive effects of both two major genes were -1.39 and the dominant effects were -6.59 and -7.91. Heritability values of the major genes in B1, B2, and F2 were 45.73%, 63.49%, and 81.12%, and those of polygenes were 27.41%, 0.95%, and 0, respectively. For plant height in the back cross, additive effects of both two major genes were -1.63 and the dominant effects were -7.03 and -4.19, respectively. Heritability values of the major genes in B1, B2, and F2 were 41.51%, 66.18%, and 81.81%,and those of polygenes were 11.19%, 0, and 0, respectively. For stem diameter in the orthogonal combination, the two major genes had 0.03 and 0.03 of additive effect and –0.50 and –0.08 of dominant effect. Heritability values of the major genes in B1, B2 and F2 were 37.26%, 48.80%, and 72.10%, and those of polygenes were 11.18%, 0, and 0, respectively. For stem diameter in the back cross, the two major genes possessed ？0.15 and ？0.15 of additive effect and ？0.30 and ？0.16 of dominant effect. The estimated heritability values in B1, B2, and F2 were 76.22%, 47.12%, and 82.51%, respectively, for the major genes and 0, 14.53%, and 0, respectively, for the polygenes. These results suggest that plant height can be selected in early generations because the heritability of major genes plus polygenes was larger than 80%, whereas proper cultivation practice may enhance lodging resistance of buck-wheat because the heritability of major genes plus polygenes was lower than 80%.