Viability of potatoÂs family selection in the early generations / Viabilidade da seleÃÃo de famÃlias de batata em geraÃÃes precoces

AUTOR(ES)
DATA DE PUBLICAÇÃO

2007

RESUMO

Potato selection is practiced according to the advancement of generations In the early generations a number of limitations hamper the genetic gains such as high number of clones use of visual selection and limited numbers of tubers from each genotype Thus research has been directed toward family selection which focus first in the selection of the best families and then clonal selection only within the selected families The purposes of this study were to verify the viability of family selection in the early generations to compare the within and between family selection with combined selection methods using different selection intensities estimate families x environments interaction and identify families with wide adaptability and phenotypic stability Six experiments were conducted in Carrancas first clonal generation (FCG) Lavras and SÃo JoÃo da Mata second clonal generation (SCG) Lavras Alfenas and CareaÃu third clonal generation (TCG) all places in the State of Minas Gerais The experimental design was randomized complete blocks with three replications and 10-plants plots except in Carrancas where four replications and 25-plants plots were used The following traits were measured tuber yield (TY) tuber average weight (TAW) percentage of large tubers (PLT) tuber specific gravity (TSG) and tuber appearance (TA) Genetic variances within families were greater than between families for most traits but heritabilities between families were almost always larger than heritabilities within families This result suggests that family selection would allow reasonable gains in the early generations Family selection was more effective than clonal selection when selection was based on the mean of all environments Expected gains from selection between and within families was superior than combined selection despite the selection intensity used They were also higher when the mean over environments were used Selection could be practiced from as early as the SCG especially if selection intensity is above 27% Families x environments interactions were significant for PLT TSG and TA showing that families did not present coincident behavior over environments Most part of families x environments interaction was due to the complex effect AMMI analysis showed similar results as the joint analysis and this method allowed to point families with broad adaptation and phenotypic stability

ASSUNTO(S)

melhoramento vegetal

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