بررسي اثرات ژن و تركيب پذيري عمومي و خصوصي صفات زراعي در پنبه به روش تلاقي داي آلل

Gene action and general and specific combining ability of agronomic characters of cotton (Gossypium hirsutum L.) using diallel cross system

Combining ability of 11 agronomic traits was evaluated in a 6x6 diallel analysis. Six parents namely Cukorova, Nazily 84, Tabladila, Siokra 324, Mehr and Sahel were used in this study. Genotypes (parents and 15 F I) were evaluated at Hashem Abad Research Station (Gorgan, Iran) in a randomized complete block design with 3 replications during 1999-2000. Data were analyzed according to Griffing (I956) Method 2, model 1 and Haymanʹs graphical analysis (1954). The results showed that Siokra 324 and Sahel were the best general combiners for most of the characters, such as plant height, number of monopodial branches, length of sympodial branches, yield, petiol length, stem diameter and boll weight. GCA and SCA variances showed the predominant role of additive gene effects in the inheritance of number and length of monopodial branches. Whereas both additive and non-additive components of genetic variances were important in the inheritance of plant height, petiol length, stem diameter, boll number, boll weight and yield. However, non-additive gene effects predominanted for earliness and number and length of sympodial branches. Hybrid Cukorova x Siokra 324 was the best specific combination for earliness and boll number. The hybrid Cukorova x Nazily 84 showed the highest positive SCA effects for most of quantitative traits. Grafic analysis of Wr-Vr showed complete dominance and partial dominance for number and length of monopodial branches, respectively. The relative position of parents along regression line for number of monopodial branches showed that Cukorova has more dominant genes and Nazily 84 has more ressesive genes while (Tabladila and mehr) have equal dominant and ressesive genes. The relative position of parents along regression line for length of monopodial branches showed that, Tabladila had more dominant genes and the rest (Cukorova, Nazily 84, Siokra 324, Mehr and Sahel) almost had equal dominant and ressesive genes.