بررسی هتروزیس و ترکیب پذیری ارقام امیدبخش پنبه ‭(.Gossypium hirsutum L) ‬به روش تلاقی دی آلل

In order to study the combining ability and hetrosis for quantitative and qualitative traits in cotton (Gossypum hirsutum L.), six promising varieties of cotton were crossed in a half-diallel design with 15 hybrids and 6 parents. There were significant differences between genotypes for 10 traits studied. Therefore, Griffing s method 2 model 1 was used to partition the genotypic effect into general combining ability (GCA) and specific combining ability (SCA) effects. Variances due to GCA effect were significant (p<0.01) for all studied traits, and variances due to SCA effect were significant for 6 studied traits. According to Baker, the ratio of [2 2gca/(2 2gca+ 2sca)] was calculated for each trait to detect the relative importance of additive and non-additive gene effects. The ratio revealed that variation for number of monopodial branches, sympodial branches length, the distance between the first node on sympodial from the main shoot, 100 seed weight and lint percentage could be attributed to additive gene effects, whereas non additive gene effect accounts for seed cotton yield, boll weight, 2.5% fiber length variation, while lint yield and micronair index is controlled by both additive and non additive gene effects. Among parents Tabladella and Shirpan-603 had the highest GCA for 100 seed weight, and Siokra and Tabladella for lint percentage produced. The highest GCA, therefore the varieties above might be the best. Thirty three percent of offsprings showed heterosis over parents mean for seed cotton yield and lint yield. The highest and the lowest heterosis mean percentage were boll weight (15.8%) and lint percentage (1.9%), respectively. The mean heterosis for Monopodial branch length was negative (-5.9%). Broad sense heritability for seed cotton yield and lint yield were 70% and 0.76, respectively and the narrow sense heritability were 0.26 and 0.35. The highest and lowest broad sense heritability were produced by boll weight (0.85), and 2.5 fiber length and micronair index (0.57), respectively. Keyword: Cotton (Gossypum hirsutum L.), Diallel, Heterosis, Heritability, Combinig ability, additive and non-additive gene effect, Yield

Keywords:

توارث , ژن , گنبد , هتروزیس , ترکیب پذیری , امیدبخش , پنبه ‭.Gossypium hirsutum L , ‬دی آلل