Inbreeding depression and genetic variability of populations for green maize production

Abstract

The production of green maize is considerable important for various regions of Brazil. It is vital that breeding programs of public institutions seek to meet the needs of this market sector, which has a relevant social role, mainly on small properties. The aim of this study was to estimate the inbreeding depression and the genetic components (m + a and d) of characters associated with green maize production and quality in three populations of different genetic basis: the variety UFG-Samambaia (P1), and two populations formed by crossing the commercial hybrids (P2 e P3). The S 1 progenies of each population, the three S 0 populations, and two checks were evaluated in a 14 × 14 triple lattice design. Agronomic and ear quality traits were evaluated. Genetic variability and greater inbreeding depression were observed for most of the traits among the P1 progenies. In P2 and P3, greater inbreeding depression was observed for male flowering, ear weight without straw, ear diameter, ear weight, female flowering, breakage and lodging, and grain color. The traits of ear quality, important for green maize production, had greater inbreeding depression than the agronomic traits, indicating that inbreeding depression and exploitation of heterosis should be considered in the selection process for these traits.

Genetic Parameters in Mesocotyl Elongation and Principal Components for Corn in High Valleys, Mexico

“…In this sense, the combinations of L × L and L × M mesocotyls had a higher ID% than the combinations L × S, M × M, M × S and S × S. Therefore, the high heterosis in F 1 of some crosses was associated with a high ID% of these combinations for LM, LC, COP1 and COP2 (Figure 10). Similar results were observed [35] between crosses of two commercial corn hybrids (P2 and P3) based on characters related to COP1 and COP2 [36] of the present study. Likewise, [37] indicates that it is important to explore germplasm with emphasis on inbreeding depression and its relationship with seedling traits and ear characters, such as ear weight and grain weight per ear of corn hybrids, to generate population base due to the high degree of genetic improvement in these genotypes, their adaptation to cultivation conditions and the presence of favorable alleles for traits of interest [37].…”

“…Later studies [2,[32][33][34][35][36][37][38][39] indicate that diallelic designs constitute a useful tool to characterize and estimate the GCA and SCA of parents and their crosses [9,40]; however, the main limitation of the use of complete diallels is the fact that the number of crosses to be evaluated increases considerably as more parents in the study are influenced [41,42]. Also, in practice, it is often not possible to obtain all the hybrid combinations possible because of different factors that include a low density of seeds, problems of fertilization and variation in adaptation, as well as losses of hybrids caused by the lack of germination.…”