Critérios na escolha de genitores e mecanismos de seleção para caracteres agronômicos nas primeiras gerações em batata (Solanum tuberosum L.) / Critérios na escolha de genitores e mecanismos de seleção para caracteres agronômicos nas primeiras gerações em batata (Solanum tuberosum L.).

AUTOR(ES)
DATA DE PUBLICAÇÃO

2006

RESUMO

The choice of parents and selection strategies when carefully defined and incorporated as usual practice in potato breeding programs, increase their efficiency and versatility. This research was composed of four studies. The work had as the main objective to analyze the use of distance measurements among potato genotypes through genealogy, morphologic and molecular markers, and jointed morphologic plus molecular markers. Thirteen cultivars and elite clones were grown in springs of 1999, 2000, 2001, 2002 and 2003, in the field. Can concluded that all estimates of genetic distances owe be considered jointly to obtain contrasting crossings. The second study aimed to estimate the combining ability of potato parents in early generations of selection. A hybrid population composed by 20 progenies in a partial diallel (4x5) arranged in a factorial design was evaluated. The results allowed infer that, number and average tuber weight are characters with CGC and CEC effects important, whereas tuber yield was a character governed by predominant additive genetic effects. In seedlings generation, the estimates of combinations capacities can is predicted. The third study was aimed to estimate genetic parameters of component traits of tuber appearance, evaluated in the two first generations of potato, aiming to estimate selection gains. The experiment was conducted in two generations, seedlings generation, in plastic house, and first clonal generation, in the field, during autumn of 2004 and 2005, respectively. A population of 15 potato families with 20 plants (genotypes) for each family was used. Can conclude that the seedling generation provide better expression of tuber appearance traits, than in the first clonal generation. High pressure of selection can be applied in early generations to shape, pointing and curving of tubers. The fourth study aimed to estimate genetic parameters of component traits of tuber appearance, evaluated in the two first generations of potato, aiming to estimate selection gains in the seedling generation. Two populations (1 and 2) were evaluated in plastic house, during autumn and spring seasons of 2004. Expected correlated and direct gains were estimated for tuber appearance and yield. In seedling generation, the expected correlated gains are bigger in tuber appearance by selecting for tuber curving, pointing and tuber shape, however lower to direct selection. The selection for tuber appearance based on its individual components does not offer possibility of higher gains that the direct selection, whereas the selection for tuber yield through its components (number and tuber medium weight) results in higher gains than direct selection.

ASSUNTO(S)

ganhos correlacionados combining ability parâmetros genéticos genetic parameters dissimilaridade genética genetic dissimilarity capacidade de combinação correlated gains melhoramento vegetal

ACESSO AO ARTIGO

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