| The estimates of SCA effects for the character studied (Tab.
2) show that out of the total 6 cross combinations three of them had
negative and three positive SCA effects in 1973, while four of them had
negative and only two positive SCA effects in 1975. No one cross combination
showed positive SCA effects in the both years which indicates a strong influence
of the environmental factors on the expression of SCA effects. HALLORAN
(1975) reported similar findings with the F4 Wheat diallels tested in the
two different environments. The highest positive SCA was shown by the combination Sava x Bezostaja-1 (1,16) in 1973 and Sava x Kavkaz (1, 19) in 1975. Because of the preponderance of additive effects in these cross combinations they could be assumed as promising combinations for selection of superior pure-line varieties. Although the wheat grain protein content in numerous studies has shown to be of a resonable strong heritability (RAM and SRIVASTAVA, 1975 ; DUFFIELD et al., 1972 and others), the data in this experiment pointed out that genetic control of this character appeared to change with environment. This behavior again points to the need to conduct protein inheritance and selection studies under environmental conditions closely appropriate to those for which higher protein genotypes are required. It seems that season to season selection within the one environment should be resonable effective in retaining a genetically high protein component of the population. The greatest advance in protein content would be expected from selection within the highest protein crosses. Literature Cited BHULLAR, B.C., GILL, K.S. and MAHAL, G.S.: Genetic analysis of protein in wheat. Fifth Inter. Wheat Genetics Symposium, Abstr. New Delhi, India, February 23-28, 1978 BROWN, C.M., WIEBEL, R.O. and SEIF, R.D.: Heterosis and combining ability in common winter wheat. Crop Sci., 6: 382-383, 1966 CHAPMAN, S.R., MCNEAL, F.H.: Gene effects for grain protein in five spring wheat crosses. Crop Sci. 10, No. 1: 45-46, 1970 DUFFIELD, R.D., CROY, L.O., SMITH, E.L.: Inheritance of nitrate reductase activity, grain protein and straw protein in a hard red winter wheat cross. Agronomy Journal, Vol. 64, p. 249-251, 1972 GRIFFING, B.: Concept of general and specific combining ability in relation to dialle crossing systems. Aust. J. Biol. Sci., 9: 463-493, 1956 GRIFFING, B. and E. ZSIROS : Heterosis associated with genotype-environment interaction. Genetics, 68: 443-445, 1971 HALLORAN. G.M.: Genetic analysis of grain protein percentage in wheat. Theoretical and Applied Genetics, 46(2): 79-86, 1975 KETATA, H., SMITH, E.L., EDWARDS, L.H., MCNEW, R.W.: Detection of epistatic, additive, and dominance variation in winter wheat (Triticum Aestivum 1. em thell.) Crop Science, V. 16(1): 1-4, 1976 RAM, H.H., SRIVASTAVA, J.P.: Inheritance of grain protein and sedimentation value in wheat. Indian Journal of Genetics and Plant Breeding, V. 35(1): 21-25, 1975 |
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