Study of combining ability in some top crosses in maize [Egypt]
1985
El-Hosary, A.A. (Zagazig Univ., Moshtohor (Egypt). Faculty of Agriculture)
Twenty-one new inbred lines of maize were top-crossed to each of four different testers. A total of 84 top crosses were obtained among them. Top crosses were tested for grain yield per plant, silking date, ear height, plant height, ear husk number of rows/ ear and number of kernels/ row. The data were analyzed according to the procedure developed by Kampthorne (1957). The magnitudes of the ratio of general to specific combining ability (g.c.a. to s.c.a.) revealed that the non-additive component of gene action had the major role in the inheritance of all the traits. The magnitude of the interactions between s.c.a. and year was generally higher than g.c.a. x year. Parental females M. 23 and G. 507A were found to be the best general combiners for yielding ability. Whereas silking M. 16, and M. 15 were significantly better general combiners for earliness. The tester G. 2 gave the highest positive g.c.a. effects for grain yield and both of its components where the tester Sabeeni proved significantly negative combiner for silking date, ear and plant heights. The greatest inter-and-intra-alleic interaction in terms of s.c.a. were observed in top-crosses s.c. 14 with each of G. 251 B, G. 227 B, G. 102 and Rg10. and crosses G. 444 x Pioner 514, G. 4 x Sabeeni for yield per plant where crosses Rg11 x s.c. 14, M. 23 x s.c. 14, G. 227 Bx pioneer 514, G. 227 B x G. 2 and G. 307 A x Sabeeni for earliness. These genetic materials would be of value of maize breeding programme in Egypt.
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