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[Objective] This study aimed to analyze the inheritance of bolting associated traits in Brassica rapa,which will provide useful information in a breeding program for late-bolting or bolting-resistant cultivars of Chinese cabbage.[Method] Three phenotypic measurements,bolting index,flowering time,days to 5 cm elongated stalk,respectively were used for inheritance analysis of six generations,P1(bolting resistant inbreed line),P2(vernalization independent type) and their filial generations F1,B1,B2and F2,using the mixed major-gene plus polygene inheritance model.[Result] The two traits,bolting index and days to 5 cm elongated stalk,both were controlled by two major genes with additive-dominant-epistatic effects( B-1 model) in hybrid. The flowering time was controlled by one major gene with additive-dominant effects plus additive-dominant-epistatic effects( D model). The heritability of the major genes in B1,B2and F2were 96. 22%,93. 33%,93. 55% for bolting index,70. 68%,70. 68%,70. 64% for flowering time,79. 44%,79. 55%,79. 38% for days to 5-cm elongated stalk,respectively,but no polygene heritability was detected in B1,B2and F2generation. It indicated that the bolting trait in Brassica rapa was controlled by one or tow major genes.[Conclusion] This implied that in the genetic improvement for bolting resistant trait major gene was a main factor. It is fit for early selection and environment factor should be mentioned.
[Objective] This study aimed to analyze the inheritance of bolting associated traits in Brassica rapa, which will provide useful information in a breeding program for late-bolting or bolting-resistant cultivars of Chinese cabbage. [Method] Three phenotypic measurements, bolting index, flowering time, days to 5 cm elongated stalk, respectively were used for inheritance analysis of six generations, P1 (bolting resistant inbreed line), P2 (vernalization independent type) and their filial generations F1, B1, B2 and F2, using the mixed major- [Result] The two traits, bolting index and days to 5 cm elongated stalk, both were controlled by two major genes with additive-dominant-epistatic effects (B-1 model) in hybrid. The flowering time was controlled by one major gene with additive-dominant effects plus additive-dominant-epistatic effects (D model). The heritability of the major genes in B1, B2 and F2were 96.22%, 93.33%, 93.55% for bolting index , 70.68%, 70.68%, 70.64% for Flowering time, 79. 44%, 79.55%, 79. 38% for days to 5-cm elongated stalk, respectively, but no polygene heritability was detected in B1, B2 and F2 generation. It indicates that the bolting trait in Brassica rapa was controlled by one or tow major genes. [Conclusion] This implied that in the genetic improvement for bolting resistant trait major gene was a main factor. It is fit for early selection and environment factor should be mentioned.