Preliminary study on inheritance of an artificially resynthesized white flower line in Brassica napus L.
A group of white flower lines of the resynthesized B. napus have been developed from the crosses between B. campestris L.and B. oleracea var. Alboglabra Bailey collected in Southwestem China. A pure white flower line, HW243 (P2), from the resynthesized B. napus was crossed reciprocally to a common B. napus cultivar Westar (P1). The F1 hybrid ofWestar×Hw243(F1) was selfed and backcrossed to both parents to obtain F2, BC1 and BC2 populations, and the variation in flower color and segregation rule were investigated with the six populations P1, P2, F1, F2, BC1 and BC2 The results showed that the petal color of F1 was milky white and there was no obvious difference in petal color between the reciprocal F1 hybrids. This indicated that the white color of the petals in the line was controlled by nuclear genes without cytoplasmic effect and that the white color was incompletely dominant to yellow color. The petal colors in the F2 population could be roughly classified into 3 classes, i.e. pure white, milky white and yellow. Based on the investigations of two seasons at two locations the ratio of plants with pure white,milky white and yellow flower in the F2 populations was 1:11:4 (P=0.8-0.9); the ratio of plants with yellow flower and milky white flower in the BC1 population was 1:1 (P=0.3-0.7), and the ratio of planns with milky white and white flower in the BC2 population was 3:1 (P=0.5-0.7). It was supposed that the white flower character in this resynthesized line was controlled by two interacting duplicate genes which were incompletely dominant to the yellow color genes. It was presumed that the genotype of white flower parent was W1W1W2W2, the genotype of yellow flower parent was w1w1w2w2, and the genotype of F1 was W1w1W2w2. The petal color of F1 was milky white. In F2, the genotype of pure white flower offspring was W1W1W2W2, taking a ratio of 1/16. The genotypes of yellow flower offspring were w1w1w2w2, w1w1W2w2 and w1w1W2W2, respectively, taking a ratio of 4/16. In the yellow color group, the homozygous w1w1 alleles were epistafic over the dominant W2 alleles. The genotypes of milky white flower offspring were W1W1W2w2, W1W1w2w2, W1w1W2W2, W1w1W2w2 and W1w1w2w2, respectively, taking a ratio of 11/16. Nevertheless, a variation in whiteness in flower color was observed in the milky color group in F2. It seemed that there was a gene-dosage effect on the whiteness of flower color, which appeared to be related to the number of dominant W1 and W2 alleles in the genome. Further investigations are necessary to fully understand the genetic rule of the white flower character.
Brassica napus L. white flower inheritance
TIAN Lushen JIANG Guangfu NIU Yingze GUO Shixing
Rapeseed research center, Sichuan Agricultural University, Yaan 625014, China
国际会议
第十二届国际油菜大会( The 12th International Rapeseed Congress)
武汉
英文
302-305
2007-03-26（万方平台首次上网日期，不代表论文的发表时间）