海岛棉纤维含糖量的遗传研究

Genetic Study on Sugar Content in Sea Island Cotton Fiber

选用果枝型和纤维含糖量不同的9个海岛棉品种(系)按5×4不完全双列杂交配制成20个杂交组合,分析了杂种F_1和F_2代纤维含糖量的遗传特点,结果表明F_1纤维含糖量具有明的负向杂种优势,遗传表现为超低亲遗传,亦有倾低亲遗传现象.亲本含糖量中亲值与杂种F _1的关系最密切,在低糖育种中应以中亲值选配亲本.含糖量是一数量性状,受微效多基因控制F_2表现为连续变异的特点,并普遍存在着超亲遗传现象,超低亲遗传为低糖育种提供了选择的遗传基础,通过杂交育种可有效地降低杂种后代的纤维含糖量,并且其遗传力(87.30%)较高,在早期世代选择是有效的.

Having Selected 9 sea island cotton specieses with thecharacters of boll-bearing branches and different sugar contents intheir fibers to form 20 hybridized combinations according to 5×4incomplete diallel cross, the genetic characters of F1 and F2fibersugar contents were analysed. It resulted that F1 fiber sugar contentshowed significantly negative hybrid vigor, and the genetic character,super-low parental genetic and also the low-tendenc-ing parental geneticphenomena; the closest relation between hybrid F2 and the medium-parental value of parental sugar content decided the use of mediumparental value as the only parent to breed the low sugar contentspecieses. Being a quantitative property and controlled by micro-effectpoly-gene, the F2 fiber sugar content displayed a continuous variation-characteristic and the usual phenomena of super-low parent hereditywhich offered a selectable genetic basis for breeding the low sugarcontent specieses,that is the fiber sugar content of hybrid progenycould be effectively decreased through Nybrid breeding, and because ofits higher genetic power(87. 30%), its early generation selection waseffective.