Estimation of general and specific combining ability for grain yield and its components in Zea mays L. diallel crosses
2002
Javid, M.
The present research project was carried out to estimate combining ability effects for grain yield and its components in six elite maize inbred lines viz., A 427-2, A 509, A 545, A 635, A 639 and OH-141 A by using Griffing's Method I, Model 1, in a 6 x 6 complete diallel experiment. The seeds from the parental inbred lines and all possible single crosses were sown in a randomized complete block design with three replications. Data were recorded for grain yield and its components viz., number of days to tussling, number of days to silking, number of ears per plant, number of kernel rows per ear, number of kernels per row, plant height (cm), 100-grain weight (g) and grain yield per plant (g) Mean squares for all the characters studied were highly significant except for number of ears per plant and plant height. Mean squares due to general and specific combining ability were also significantly for all the characters. Variance due to specific combining ability (SCA) was greater in magnitude and was more important for all the characters, than the variance of general combining ability (GCA). These results revealed that the inheritance of these characters is governed by non-additive type of gene action. Regarding the ultimate breeding objective grain yield per plant, inbred line OH-41 A was the best general combine and the best specific combination was A 509 x OH-41. A while the cross combination OH-41 A x A 635 displayed the best reciprocal effects. The inferences drawn here in strictly statistical senses apply only for these specific lines involved. However, since these lines comprise a representative sample of the material available for our breeding performance, the present findings may be reviewed in a broader sense.
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