Performance of Open-Pollinated Maize Cultivars selected from 10 Tropical Maize Populations
Open-pollinated cultivars (OPCs) continue to occupy a larger portion of maize (Zea mays L.) production area than hybrids in the developing countries. We studied the possibility of extracting superior OPCs during an ongoing recurrent selection program for use in the developing countries. Forty experimental cultivars (ECs) were developed from 10 maize populations adapted to lowland tropics, using 7 to 14 full-sib families. Families were selected for performance at one site (Poza Rica, Mexico) or across five to six sites, (Across) around the world, from CO (ECs-C0) or from C3 or (ECs-last cycle). The effects of selection were evaluated in four environments to measure performance and stability. Percent superiority of ECs-last cycle over ECs-C0 was 9.5 (P < 0.01) for yield, −2.6 for days to 50% silking, −5.1 for plant height, −9.6 for ear height, 5.6 for ears per plant, 1.9 for 1000-seed weight, and −11.7 for ear rating. Poza Rica-ECs were lower (P < 0.01 ) in plant and ear height (−6.1 and −10.3%, respectively) than Across-ECs daring summer at Poza Rica and Across-ECs had fewer (−1.19%) days to 50% silking than Poza Rica-ECs at the other three sites. for yield, the b1 (regression of entry means to environmental index) values for Across ECs-last cycle were lower than those for Poza Rica ECs-C0, Across ECs-C0, and Poza Rica ECs-last cycle (P < 0.01 and P < 0.25 with environments considered fixed and random, respectively). The results indicate that ECs developed from advanced cycles of selection of populations undergoing recurrent selection yield higher (P < 0.01) and are more stable (P < 0.01 and P < 0.12 with environments considered fixed and random, respectively) than those developed from the original cycle.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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