Cruzamentos dialélicos entre linhagens de milho crioulo

Abstract

This work deals with the utilization of landrace maize populations to develop inbred lines, in order to achieve hybrids of high performance. In addition, it proposes the consideration of physiological attributes in the breeding process as a way to promote the development of more adaptable and yielding genotypes. Therefore, the objective of this work was to access information on the genetic control of physiological, morphological and yield components, as well as to estimate the combining abilities of maize inbred lines developed from landrace populations of the Rio Grande do Sul state. Furthermore, to verify the correlation between genetic distances among genitors and their hybrid´s heterosis. The experiments were conducted in two agricultural years, in the experimental area of the Plant Genomics and Breeding Center of the Federal University of Pelotas. The crosses were carried out in the 2016/2017 growing season, using six inbred lines, resulting in 30 F1 hybrids. These hybrids, along with the genitor lines, were conducted in a randomized complete blocks design during the 2017/2018 growing season, with three replications. The dataset regarding physiological traits was submitted to Hayman´s diallel analysis, while the information concerning yield components and morphological characters were submitted to Griffing´s diallel analysis. The genetic dissimilarity between genitors was estimated through the generalized distance of Mahalanobis, and their correlation with the hybrids´heterosis was verified for all traits. The non-additive gene actions predominate in the genetic control of yield components and morphological traits. The highest value of heterosis observed for grain yield per plot occurs through the crossing CGF 01 × CGF 03. Allelic interactions of complete dominance and overdominance are observed for chlorophyll index; complete dominance for flavonoid index; and complete dominance and additivity for nitrogen balance index. The genitors indicated by Hayman's diallel analysis have the potential to increase their respective traits, however, it is necessary to seek for suitable combinations in a larger group of genitors. There is no correlation between genetic distances among genitors and the superior performance of their hybrids, for the set of traits analyzed.