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Combining ability among fifteen early cycle maize populations in Brazil

Elto E. Gomes e Gama^I; Arnel R. Hallauer^II; Mauricio A. Lopes^I; Sidney N. Parentoni^I; Manoel X. dos Santos^I; Paulo E.O. Guimarães^I

^ICNPMS/EMBRAPA, Caixa Postal 151, 35701-970 Sete Lagoas, MG, Brasil
^IIDepartment of Agronomy, Iowa State University, Ames, Iowa 50011, USA. Send correspondence to A.R.H.

ABSTRACT

Early maturity maize (Zea mays L.) populations are used in short growing season areas, and their use is gradually increasing in tropical areas. The objective of this study was to determine the genetic potential of 15 early maturity maize populations in a diallel crossing system. The 15 parents, 105 diallel crosses among parents, and selfed generation of parents were evaluated in a triple lattice design at 13 locations in Brazil. The combined analyses of variance for grain yield, time to tassel, and plant height indicated highly significant (P < 0.01) differences for entries, parents, heterosis, parent heterosis, specific heterosis and for the first-order interactions with environments. Average heterosis was highly significant for grain yield, significant (P < 0.05) for time to tassel, and not significant for plant height. Mean yield ranged from 3187 to 5213 kg/ha for populations, and ranged from 3041 to 6017 kg/ha for the population crosses. Population Pool 17 had the largest inbreeding depression effects, whereas population CMS 52 had the smallest inbreeding depression effects. The highest specific cross for grain yield was for Across 8528 x Pool 18. None of the population crosses was superior to the hybrid checks for the three traits. No association was found between endosperm type and heterosis. The results suggest that either the populations themselves or the synthetic composites of selected populations can be used for breeding purposes.

Keywords: maize populations.

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