Study On Dynamic Genetics Of Main Quality Characters Of Flue-cured Tobacco

Six parental flue-cured tobacco varieties(lines) were used for diallel cross based on {p·(p-1)/2} design to get genetic materials including parental lines and two generations of F₁s. Estimates of genetic effects for total sugar, total nitrogen, nicotine ,ratio of sugar to nicotine ,ratio of nitrogen to nicotine , Schmuck value of flue-cured tobacco at some developmental stages(0→13-leaf) or some special developmental periods(7 | 5, 9 | 7, 11 | 9, 13| 11)were conducted by using additive-dominant genetic model and developmental genetic model for quantitative traits.Analysis on unconditional genetic variance revealed that during the six quality characters of flue-cured tobacco, the ratio of nitrogen to nicotine was mainly controlled by dominant effects, and the rest quality characters of flue-cured tobacco were affected by dominant and additive effects, but the rest were mainly controlled by dominant effects, the expression of dominant and additive effects was concentrated on the 7-leaf stage and the 9-leaf stage. Analysis on conditional genetic variance indicated that the characters of total sugar, nicotine, ratio of nitrogen to nicotine were expressed slightly by additive effects, the others were mainly controlled by dominant effects, also were expressed from 7-leaf stage to 9-leaf stage(9 | 7) and 9-leaf stage to11-leaf stage(11 | 9) .The others were also expressed by dominant gene effects.The results for unconditional heritabilities analysis suggested that narrow sense heritabilities except ratio of sugar to nicotine expressed zero, the others were mainly expressed on the 7-leaf stage, but it was detected slightly. Estimated on conditional heritabilities, it found that the narrow sense heritabilities of total nitrogen ,ratio of sugar to nicotine expressed zero, the residual quality characters expressed so less that the selection for flue-cured tobacco become difficulty.Dynamic analysis on heterosis for main characters in flue-tabocco at different...