Relative efficiencies of methods of selection of inbred progenies of popcorn / Eficiência relativa de métodos de seleção de progênies endogâmicas de milho-pipoca

AUTOR(ES)
DATA DE PUBLICAÇÃO

2006

RESUMO

Aiming at to evaluate the relative efficiency of different methods of selection of lines, for production of popcorn hybrid with high productivity and quality, it was aimed at: i) to compare and to evaluate the relative efficiency of the mass selection, selection among and within and combined selection of family following by selection within; ii) to evaluate the importance of performance of S3 families, as predictor of its performance in crossing and; iii) to select four groups of 20 S5 families. Were used data of 290 S1 families and 687 S1 plants, 253 S2 families and 772 S2 plants, 229 S3 families and 872 S3 plants, 249 S4 families and 661 S4 plants and 174 S5 families and 599 S5 plants, obtained of the Viçosa population, belonging to the germoplasma bank of the Sector of Genetics, of the Biology Department of the Viçosa Federal University. Topcross data of obtained from crossing among S3 families with the Beija-Flor population were also used. The mass selection consisted of the selection of plants, the selection among and within consisted in the selection of families and, later to the selection of plants within of these families and, the combined selection consisted of the selection of families for the combined index selection proposed and, later, the selection of plants within of these families (selection within). It was selected in popping expansion and simultaneously in popping expansion and yield, with aid of the index of Mulamba and Mock (1978), with weight 3 in popping expansion and 1 in yield. The relative efficiency of the selection methods was evaluated by the comparison of averages among different groups of Sn families, obtained by selection with base in the three methods in Sn- 1. They were made four selection cycles, of S1 to S4. With the rehearsal of topcross hybrid, its felt the association among performance of S3 families and performance in crossing of S3 families, for the I make calculations of the correlation among father (S3 family) and son ( topcross hybrid), considering yield and popping expansion. It was ended that: i) in general, a larger efficiency of the combined selection following by the selection within and of the selection among and within, relatively to the mass selection; ii) the combined selection following by the selection within and the selection among and within they presented, in general, resulted practically equivalent in the selection practiced in the S1, S2, and S3 generations. However, the combined selection following by the selection within overcame the selection among and within in the selection done in the rehearsal of S4 families and, it presented a tendency of efficiency increase, relatively to the selection among and within, with the increase of the inbreeding depression; iii) the use of the index of selection of Mulamba and Mock, with weight 3 for popping expansion and 1 for yield provided, in general, satisfactory gains in popping expansion and yield; iv) the performance of S3 families was not a good predictor in crossing, so much for popping expansion and yield; v) the hybrid of popping expansion higher were, in general, obtained of S3 families of medium and high popping expansion.

ASSUNTO(S)

produção de linhagens milho-pipoca methods of selection popcorn métodos de seleção genetica quantitativa production lines

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