| An additive-dominance genetic model and corresponding statistical approaches were used to analyze 11 yield and quality traits of kenaf, and the developmental behavior of gene expression for plant height and stem diameter at different growing stages.The results of genetic analysis for yield and quality traits of kenaf showed as follows. (1)Plant height, fresh bark thickness, fibre fineness were controlled by additive gene action and dominant gene action. Stem diameter, dry bark wcigllt per plant, dry stem weight per plant, bark rate, rate of bark and jarkstraw, fibre weight per plant, retting rate, fibre strength were mainly controlled by dominant gene action. Narrow heritabilities of plant height, fresh bark thickness, fibre fineness were significant, while the other traits were not. Broad heritabilities of all traits were significant. So, the better selecting effects for plant height, fresh bark thickness, fibre fineness could be expected in early generations; the selection of other traits must be conducted in high generations to avoid the interference of dominant gene action.(2) Correlation analysis showed that the dominance correlations between plant height and dry bark weight per plant, dry stem weight per plant, and fibre weight per plant were significant at 0.01 level, their additive correlations were significant at 0.1 level. Plant height might be simultaneously selected with dry bark weight per plant, dry stem weight per plant, and fibre weight per plant in hybrid combination. Fresh bark thickness had the same correlations as plant height. No additive correlation was found between stem diameter and the other traits. The dominance correlations between stem diameter and plant height, fresh bark thickness, dry bark weight per plant, dry stem weight per plant, and fibre weight per plant were significant. Yield traits had negative correlation with quality traits. But fibre fineness and fibre strength all had significant positive correlations with rate of bark and jarkstraw. Indirect selection was expected for fibre fineness and fibre strength through rate of bark and jarkstraw. Fibre fineness existed nagetive correlation with fibre strength.(3) Among all traits dry bark weight per plant, dry stem weight per plant, fibre weight per plant and fibre strength had mainly F1 heterosis over mid-parent and FI heterosis over better parent. F2 heterosis over mid-parent was similar to F1. But most traits had negative p2 heterosis over better parent, except for dry bark weight per plant, dry stem weight per plant, fibre weight per plant and plant height.(4)Each parent had different genetic effect. Predicted genetic effects of yield traits showed that Fuhong 2, Fuhong 992 and Feizhong leiye were better than other parents, their genetic effects could improve the yield of kenaf. Some parents such as Fuhong 2, Fuhong 992 were better than others for improving the quality of kenaf.The results of genetic analysis for plant height and stem diameter at different stages showed as follows.(l)Dominance effect played more important role at different stages for plant height, while additive effect was weak. No additive effect was found for stem diameter, but dominance effect was significant at each stage. Plant height and stem diameter all had activegene expression from July 28 to August 9, September 2 to September 14.(2) Additive correlation between plant height and the other traits varied with traits and stages, but positive dominance correlation existed all the time. Positive dominance correlation was detected between stem diameter and the other traits, but no additive correlation existed.(3) After August 9, Ft unconditional heterosis of plant height was significant. After July 16, FI unconditional heterosis over mid-parent of stem diameter was significant; FI conditional heterosis over mid-parent was significant at all stages.The results of unconditional and conditional genetic effects of plant height and stem diameter were not completely the same. According to practice, conditional genetic analysi... |
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