Analysis Of Combining Ability And Hybrids Heterosis For Six Upland Cotton Parents

Thirty cross combinations were produced using a complete diallel-mating system with six upland cotton varieties or lines to discuss the genetic effect of parents and to screen high-yield hybrids according to the performance of agronomic traits, seed and lint yield. The main results are as follows:1. In 30 hybrid combinations, cross 28 was characteristics of excellently comprehensive agronomic traits and dramaticly significant lint yield with avarage 122.3 cm height,15.44 fruit branchs,46.4 bolls per plant,5.49 g boll weight,43.66% lint percentage,300.67 kg seed yield and 125.38 kg lint yield in 667 m. Crosses 21,22 and 5 also had good comprehensive agronomic traits and significant seed and lint yield with 40.87-47.67 bolls per plant,98.67-314.6 kg seed and 122.65-123.64 kg lint yield in 667 m2, kilograms. These crosses were recommend into the next turn comparetive experiments considering the influence of climate factors in different years..2. The narrow and broad heritability of plant height, number of fruit branch, boll-setting numbers, boll weight, lint and seed cotton yield reached a extremely significant level. Boll-setting per plant of the 30 cross combinations was mainly controlled by additive effect, had non-addive effect. However, boll weight, lint percentage, seed and lint cotton yield and plant height were mainly affected by additive effect, and also partly controlled by dominant and maternal effect. The number of fruit branch was mainly controlled by additive effect with a little of maternal effect and non-dominant effect.3. In six upland cotton parents, P5 and P6 had the highest general combining ability in boll number per plant, P2 and P6 in lint percentage, P5 in boll weight and P2 (Xianmian 10) in seed cotton yield. The number of bolls per plant was mainly controlled by additive genetic effects, independent of the control of non-additive effect. Lint percentage was mainly controlled by additive effects and also affected by non-additive effect to some extent. The general combining ability of boll weight, which was mainly cotrolled by additive effect, was similar with the lint percentage.