Genetic Correlation Analysis And Combining Ability Of Quantitative Traits For The Sea Island Cotton

The Sea Island Cotton was famous for good fiber characters in planting cotton all over the world .Many experts had studied genetics aspects of the Upland Cotton, but the reports were less for the Sea Island Cotton at present. This research had systematically discussed hybrid F₁ and F₂ heredity rule of the Sea Island Cotton in Xinjiang region.1.Lint percent, lint index, boll weight, fallen rate, fruit-branch number ,fiber strength, fiber elongation ratio and fiber length,s heredity were mainly controled by additive gene; the pre-frost lint yield, yield, seed index, boll number had a high heredity,too. Simultaneously was influenced by dominance and environment effect; plant height, micronaire, fiber uniformity had a high dominant effect. Lint percent,fiber length conformed to the additive - dominant– epistasis model; boll weight conformed to the additive-epistasis model; fiber strength, micronaire conformed to the additive model; boll number, seed yield conformed to additive - dominant model.2.The correlation analysis indicated that most traits (F₁,F₂) had remarkable or extremely remarkable correlation with mid-parent value.F₁,F₂ yield traits (sub-seed index) becomes positive correlation.The path analysis indicated that lint percent and boll number of direct influence was biggest, boll wight was lower; The textile fiber quality (sub-fiber elongation ratio) became much negative correlation with yield traits(sub- seed index);the fiber traits (sub- micronaire) became positive correlation;The fiber traits with boll opening time, pre-frost yield rate were negative correlation;The main economical traits with plant height, the stem perimeter and leaf length were remarkably positive correlation.3. Heterosis performance F₁ seed yield was biggest superiority on yield traits, F₂ had a little drop on yield traits, boll number droped sharply; F₁ had a certain superiority in the main textile fiber traits, F₂ (sub-fiber elongation) had a little drop to F₁.F₁ had a certain superiority in nutrition,s traits, the fallen rate was lower than that of mid-parents; The first fruit-branch was lower of F₂,the period of duration reduced, the pre-frost yield rate enhanced; The weight of mid-boll was heavier, and the bottom and top boll difference was not obvious;The boll weight of long-fruit-branch type cotton was higher than zero-type-fruit-branch,s, but the fiber quality were worse than that of zero-type,s;The reproductive organ dry weight/all material heavy ratio of F₁was higher than that of F₂.4.Through the combining ability analysis for parents and hybrids:xinhai15 GCA synthesis performance was best, xinhai 16×xinhai 15 was the superior crossing combination.It had a superiority (20.4%)over high-parent on lint yield,and had 12.9% times more than CK on lint yield.