ABSTRACT
Reciprocal recurrent selection (RRS) has been successfully applied to maize breeding for more than 60 years. Our objective was to assess the relative efficiency of the genotypic value and the effects of general and specific combining abilities (GCA and SCA) on selection. The GCA effect reflects the number of favorable genes in the parent. The SCA effect primarily reflects the differences in the gene frequencies between the parents. We simulated three traits, three classes of populations, and 10 cycles of half- and full-sib RRS. The RRS is a highly efficient process for intra- and interpopulation breeding, regardless of the trait or the level of divergence among the populations. The RRS increases the heterosis of the interpopulation cross when there is dominance, and it decreases the inbreeding depression in the populations and the genetic variability in the populations and in the hybrid. When there is not dominance and the populations are not divergent, the RRS also determines population differentiation. The half-sib RRS, which is equivalent to selection based on the GCA effect, is more efficient than the full-sib RRS based on the genotypic value, regardless of the trait or the level of improvement of the populations. The full-sib RRS based on the SCA effect is not efficient for intra- and interpopulation breeding.
Subject(s)
Breeding/methods , Models, Genetic , Selection, Genetic , Zea mays/genetics , Computer Simulation , Gene Frequency , Genes, Plant/genetics , Genetics, Population , GenotypeABSTRACT
O presente trabalho tem por objetivo avaliar novas linhagens de triticale, em dois locais do Estado de Minas Gerais, visando à seleção de novos genótipos para serem multiplicados e distribuídos aos agricultores. Os experimentos foram constituídos de 13 linhagens de triticale e três cultivares de trigo, em delineamento estatístico de blocos ao acaso com três repetiçoes. Foi avaliado o rendimento de grãos e o peso hectolitro. As análises de variância individuais e conjunta demonstraram efeitos significativos de genótipos para as características avaliadas e significativos quando considerado genótipo x local. Todas as linhagens de triticale apresentaram altas produtividades, bem maiores que as obtidas pelas cultivares de trigo. As altas produtividades destas linhagens de triticale demonstram o alto potencial destes genótipos para ser avaliados em futuros ensaios de competição, para o lançamento de futuras cultivares, com destaque, considerando as variáveis avaliadas, para as linhagens EP 068009, EP 068012, EP 068055 e EP 068050, nos dois locais cultivados. O peso do hectolitro das linhagens de triticale foi baixo (média igual a 73,5 kg/hl), o que pode ser explicado pelo comprimento dos grãos e a sua forma, além do fator genético resultante do cruzamento trigo x centeio.
The objective of this work was to evaluate the new breeds lines of triticale in the regions of Minas Gerais state aiming the selection of new germoplasma to be multiplied and distributed among agricultors. The experiments were constituted by 13 lines of triticale and 3 cultivars of wheat ramdomly in block. The grains growth and produce and the yield hectoliter weight, were evaluated. The analizes of individual and group variations presented highly significant variation. All lines presented high productivity, greater than the ones cultivated by wheat. The high productivity of the triticale lines demostrate the material great potential to be analized in future competitional experiments envisioning the future cultivational methods to be launched, outlining the EP 068009, EP 068012, EP 068050 e EP 068055 genotypes in both cultivated ambient. The yield hectoliter weight, of the triticale lines were very low, what can be explained by the grain length and shape, besides the genetic factor as the result of wheat x rye.
Subject(s)
Crop Production , Plant Breeding , Triticale , TriticumABSTRACT
A seca pode ser considerada como o principal estresse ambiental afetando diretamente a produtividade das culturas em todo o mundo. Para expandir o cultivo do trigo para áreas em condições deste estresse, se faz necessário que os programas de melhoramento direcionem suas linhas de pesquisas para essa realidade. O objetivo deste trabalho foi avaliar os componentes da interação genótipo x ambiente e a produtividade em onze genótipos de T. aestivum L., em condição de sequeiro, em dois locais do Estado de Minas Gerais (Rio Paranaíba e Patos de Minas), durante dois anos (2007 e 2008). O delineamento estatístico utilizado foi o de blocos ao acaso, com onze tratamentos e quatro repetições, nos anos agrícolas de 2007 e 2008. Há participação dos efeitos de locais e safra agrícola na expressão dos genótipos. A porcentagem da interação de natureza complexa é maior que a de natureza simples na maioria dos ambientes. E os genótipos EP 011106, IAC 289-L4 e IAC 350 estiveram entre os mais produtivos em todos os ambientes e safras agrícolas, demonstrando seu potencial como opção de cultivo de sequeiro.
Dry seasons can be considered as the main cause of environmental stress affecting the productivity of crops in the whole world. In order to expand the wheat croplands for areas with that environmental stress conditions, it is necessary that the genetic improvement programs focus their research for this reality. The objective of this work was to evaluate the components of the interaction genotype and environment and the productivity of eleven genotypes of T. aestivum L., in rainfed conditions, in two locations at the Minas Gerais State (Rio Paranaíba and Patos de Minas). The statistical design used was randomized blocks, with eleven treatments and four replications, in the agricultural years of 2007 and 2008. There are participations of location and agricultural harvest effects on the expression of the genotypes. Interaction percentages of complex nature is greater than simple nature ones in the majority of environments. The genotypes EP 011106, IAC 289-L4 and IAC 350 had been the most productive, in all environments, showing their potential as option for sowing in rainfed conditions.
