THE DIVERSITY OF SOME MAIZE INBRED LINES

Genotype diversity (morphological, ecological in the mechanisms of heterosis, through the action of the complementary favorable additive genes, favorable intrallelic and interallelic interactions, and even through the interactions between the nuclear genetic systems and the cytoplasmic factors. (MOLL et al. 1962, LAMKEY and EDWARDS 1999, ). The phenotypic and genetic diversity of maize inbred lines was particularly necessary in the creation of hybrids, being fundamental phenomenon of heterosis, the main route prevention of genetic vulnerability, thereby obtaining hybrid combinations preferred by growers or by seed producers. Results published by DUVIK (1999) that were compared hybrids and inbred lines of different selection periods converge to the conclusion that the extent of accumulation in advanced cycles of selection of favorable genes inbred lines of additive effects, production capacity ,,per se '' them is higher and heterosis values even if a lower capacity of the new hybrids is higher. By combining elements that help to achieve production capacity to reach a significantly higher heterosis. The study presents an estimate of the diversity of some new inbred lines, the heterosis and the relationship between diversity and heterosis. We used as parental forms 5 inbred lines considered as indicators of heterotic groups and 12 lines, new creations of the maize breeding team at S.C.D.A. Turda. By cross-breeding these lines, 70 simple hybrids were obtained that were experimented on in comparative cultures for 3 years. The obtained data was processed and we established the phenotypic differentiation index (IDF), the heterosis in the simple hybrids (Hallauer and Miranda 1981), the genetic diversity both at additive and non-additive levels, as well as the correlations between the diversity indicators. The results that we obtained lead us to the conclusion that the most efficient discrimination of the diversity of the inbred lines can be realized by simultaneously taking into consideration both quantitative indicators of diversity - Hr%, IDF and IDĝ+Σs mn.