Abstract:

Optimal plant architecture contribute to the increase of photosynthesis efficiency and cotton yield. Little information is available about the inheritance and heterosis of plant architecture characters in upland cotton. The objective of this study were to evaluate the genetic effects and heterosis of plant architecture characters in a population made by crossing five Bacillus thuringiensis(Bt) transgenic cotton varieties as males and five nontransgenic lines with high fiber strength as females, and analyze the interrelationships between plant architecture characters and yield and yield components. The results showed the mean mid-parent heterosis of plant height, height of the first fruiting branch, fruiting branch number and fruiting node number were rather low, but expressed large variations among diverse cotton crosses. The four plant architecture characters exhibited primarily additive genetic effects. The genetic correlations between plant height and bolls per plant, single plant lint yield were found positive and significant at 0.01 level. Fruit branch number was positively related with bolls per plant, but was negatively correlated with boll weight. There were significant positive relationships between fruit node number and bolls per plant, lint percentage, single plant lint yield. The relationship between plant architecture traits and yield traits was mainly due to the correlation between fruit node number and bolls per plant, boll weight.