Utilization of narrow base testers for evaluating combining ability of newly developed yellow maize inbred lines (Zea mays L.) [electronic resource].

Includes references.

Fourteen S₃ yellow maize inbred lines. derived from the wide genetic base population Giza-45 (EV-3), were topcrossed to each of three yellow maize inbred testers. i.e. Gz 638, Gm 1002 and Gm 1021. The 42 topcrosses were evaluated in 1999 at Sakha, Gemmeiza and Sids Agric. Res. Stations for grain yield, resistaoce to late wilt disease. silking date, plant height and ear position. Testers contributed much more than the lines to the total genetic variation and were more affected by the environmental conditions. The inbred testers ranked the 14 inbreds differently. Parental females L-2, L-4, L-7 and L-10 were found to be the best general combiner for high yielding ability. Parental lines L-2. L- 4. L-6, L-13 and L-14 were good donors for resistance to late wilt disease. L-4, L-5, L-7, L- 9 and L-12 were significantly better general combiners for earliness. Inbred tester Gm 1021 manifested highest average performance of grain yield compared to testcrosses of Gz 63 8 or Gm 1002. Results showed that Gm 1021 crossed to inbreds L-10, L-2 and L-7 would produce the best single crosses which significantly outyield the yellow commercial check hybrid SC 161 (30.60 ard/fed) by 7.03, 5.61 and 5.14 ard/fed, respectively. The cross (L-10 x Gm 1021) significantly outyielded the best white check SC 10 (33.24 ard/fed) by 4.39 ard/fed. and showed positive significant SCA effects for grain yield.

Summary in Arabic.

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