Evaluation of Maize “Turda” Germplasm as Sources of Earliness in Breeding Programs

Abstract

Evaluation of the early maize ( Zea mays L.) germplasm is important for the development of new inbred lines and commercial hybrids adapted to cooler regions. Choice of populations to use in improving elite maize hybrids is a critical decision in maize breeding programs. Our objectives were: I) to examine the variation for earliness in a set of 256 local populations, 56 synthetic populations and 504 inbred lines; II) to determine the performance and heterosis of this germplasm; III) to identify the genotypes (local populations, inbred lines) for the initiation of the primary cycle for directional selection for the studied characters. Seven synthetic populations and six inbred lines formed the base material of this genetic study. The seven synthetic populations and their topcrosses to four inbred lines: two flint inbred lines (TD 233 and CO 255) and two dent inbred lines (TC 184 and TC 209) and also a diallel type p(p-1) system with 30 single-cross hybrids and the six parental forms were evaluated at four environments in: two years 2009 and 2010 and two locations Turda and Targu- Mures. The highest values of additive effects for grain dry matter content were recorded at: Tu Syn Mara (ĝ n = +1.80), Tu SRR 5D (2I) (1) (ĝn = +0.62) and Tu Syn 1 (ĝn = +0.45). Therefore, Tu Syn Mara, Tu SRR 5D (2I)(1) and Tu Syn 1 produced hybrids with the most early maturity. The highest general combining ability (GCA) for dry matter accumulation in grains has registered the inbred lines TC209 (ĝ = +1.36) and TC208 (ĝ = +0.71).