Teor de proteína no grão em populações de milho de alta qualidade protéica e seus cruzamentos

Abstract

Corn is employed in animal feed as an energy source, but as a protein source it is deficient in lysine and triptophan. Thus, the present study evaluated open pollinated populations of quality protein maize (QPM) and their crosses for total grain protein. The heterosis and its components were quantified as useful parameters for breeding these populations. The analyses were carried out on 96 hybrids, derived from eight populations of dent grains (group 1) and thirteen of flint grains (group 2), including their parents in a partial diallel intergroup design. Kjeldahl's method was used to analyse total protein content. Variance analysis results were significant for all effects, revealing heterogeneity among and within the groups, as well as the presence of heterosis. The total protein content means of group 1 and group 2 were 9.67 g/100g and 10.51 g/100g, respectively, and the mean of hybrid combinations was 11.86 g/100g. The general mean involving all parents and crosses was 11.61 g/100g. The average heterosis was 17.58%, revealing the superiority of the hybrids over the parents. As far as general combining ability and yield mean are concerned, the best parents were CMS 454, CMS 474 and ZQP 103 (group 1) and CMS 453, BR 473, CMS 463, CMS 458 and ZQP 102 (group 2). These populations are recommended for QPM composites with high protein content.