Analysis Of Genetic Effects And Correlation Of Main Economic Characters Of Insect-Resistant Hybrid Cotton

This study used five insect-resistant upland cotton cultivars (or lines)as female parents and six non-resistant upland cotton cultivars(or lines) as male parents, 30 crosses were made by NCâ…¡heredity copulation design,to study the heterosis of the main quality and yield characters in insect-resistant F₁ hybrid cotton, and according to the quantity genetics analysis method to research combining ability of different parent and character ,the genetic effect and relevance of various characters .Through studying the heterosis of main characters to choose the model combinations of hybrid F₁,using these model combinations to study the heterosis and variation coefficient of F₂,to discuss the use value of the insect-resistant hybrid F₂. The main results were as following:1 Heterosis The heterosis analysis of the insect-resistant hybrid cotton indicated that in the yield and quality aspects were obvious, the hybrid F₁ generation is biggest in the lint cotton yield and bolls per plant, the average mid-parent heterosis were 92.30% and 45.67%,the average competitive advantage respectively was 16.88% and 15.97%; In the fiber quality aspect, the average mid-parent heterosis and competitive advantage of 2.5% span length(fiber length),suniformity and pecific strength were all positive, the average superiority respectively were 3.51% and 1.09%, 1.67% and 0.83%, 0.62% and 1.11%.2 Combining ability The different anti-insect and non-anti-insect cotton of parents had big general combining ability difference in the main characters.The anti-insect gene female parents Zhong 41,D17 and non-anti-insect male parents BN527, HN68 had big general combining ability in the main characters ,they were all the quite ideal parents.The combinations of A1B4, A2B5, A2B6, A4B1 and A4B6 were good in the yield character aspect , the combinations of A₁B₁,A₁B₂,A₁B₅,A₂B₁,A₂B₄,A₃B₆ and A₅B₂ had higher special combining ability effect value in the main quality characters.3 Genetic effect analysis The yield and quality character of the anti-insect hybrid cotton were mainly the additive heredities, the individual character follows certain dominant effect, simultaneously affected by the environment; The lint percent and seed percentage in the yield characters had higher hereditary capacity , the hereditary capacity of the quality characters (except the uniformity) were all high, showed that the phenotype variation of these characters were majority the hereditary change, and the additive function was big, not easily influent by the environmental condition ; The genetic variation coefficient analysis indicated that the main hybrid the quality characters' genetic variation coefficient were all small.4 Correlation analysis The genetic correlation coefficient of single lint cotton yield with bolls of per plant and lint percentage all achieved remarkable and the extremely remarkable level, respectively was 0.448 and 0.514. The bolls of per plant, boll weight and lint percentage three between presented related, through the parent match, these three characters may enhanced the same time;The correlation analysis of various qualities character indicated that, the genetic correlation coefficientfiber of length with fiber strength and uniformity was positive, and reached the extremely remarkable level with uniformity, with the micronairewere the inverse correlation,therefore, the enhancement of cotton fibre length following the improvement of the strength, uniformity and micronaire.5 The F₂ heterosis analysis Some combinations had certain mid-parent heterosis and superiority hybrid one generationin on the main hybrid and quality character. The coefficient of variation analysis indicated that the variation of hybrid F₂ generation was not big in the textile fiber quality and some main yield characters , so the hybrid two generations could be used in the field through selectiving the hybrid F₁ combinations with stronger advantage.6 The research of brown cotton The hybrid combinations of brown cotton has certainly positive mid-parent heterosis in the yield and quality aspects, the cotton yield and fiber quality reduce along with the deepening of fiber color, the half tint cotton and the white cotton are not remarkable in the main yield and the quality characters,so it can enhance the yield and fiber quality of brown cotton through crossbreeding with white cotton and brown cotton .