ESTIMATION OF HETROSIS, GENERAL AND SPECIFIC COMBINING ABILITY USING DIALLEL CROSS IN MAIZE (Zea mays L.)

Abstract

Five maize genotypes (CMT 033066, CMT 033060, CMTQ 033072, CMS 983046, CMTQ 033070) were used in 5x5 diallel crossing with out reciprocals. Combining ability for some quantitative and physiological traits was studied. F1 hybrids and the parental genotypes were grown in a Randomized Complete Block Design with three replications. The analysis of data carried out according to Griffing (1956) Method 2 (fixed model). Significant mean squares due to genotypes were exhibited for all traits. Highly significant mean squares due to GCA was exhibited for all traits , except Photosynthetic rate which was found non significant. Also highly significant mean squares due to SCA was obtained for all traits except, photosynthetic rate, transpiration rate which was significant only and stomatal conductance was found not significant .The ratio 2GCA/2SCA was less than one for all traits, indicating the importance of non additive gene effect, with the exception of plant height which was more than one, indicating the importance of additive gene effect, and the average degree of dominance values was more than one for all traits, except plant high, indicating the over dominance gene effect role in controlling these characters. Heritability in broad sense was high for all studied characters, while in narrow sense heritability was high for plant height only, moderate for transpiration rate and stomatal conductance and low for the remainder traits.