Selection intensities of families and clones in potato breeding

Abstract

Families selection has not been recommended as a selection method for vegetative propagated species. To verify its utility for potato improvement a series of experiments were carried out under warm temperatures (rainy season). Thirty clonal families originated from heat tolerant parents were evaluated for tuber yield and specific gravity. After obtaining the seedling generation (SG) and the first clonal generation (FCG) individual clones from a further two generations were assessed. Simulations were conducted with different intensities of family selection in SG and FCG and intensities of clonal selection in subsequent generations. The results show that family selection intensities between 50% and 60% allowed the greatest gains. Estimates of h 2 at the families level were always higher than at the clones level and corroborate for the more effective selection of families in early generations. The selection of families for tuber specific gravity can be made in the early generations (SG and FCG) regardless of the temperature conditions where the individual clones will be selected. The sequential selection of families with intensities of 60% (SG) and 60% (FCG) would promote greater efficiency for the selection of clones in second or third clonal generation. In the case of applying stronger selection intensities for a higher efficiency with sequential selection (SG and FCG) weaker intensities should be applied in the SG (  60%) and stronger intensity in FCG (  40%). Family selection for tuber yield could be practiced in the FCG as long as the selection of clones was not held in contrasting temperature conditions. Index terms: Sequential selection, computer simulation, Solanum tuberosum. RESUMOA seleção de famílias não tem sido um método recomendado para a seleção de plantas de propagação vegetativa. Para verificar sua utilidade no melhoramento da batata, realizou-se uma série de experimentos em condições de temperaturas elevadas (safra das águas). Trinta famílias clonais provenientes de genitores tolerantes ao calor foram avaliadas para produção e peso específico de tubérculos. Depois de obtidas a geração seedling (GS) e a primeira geração clonal (PGC) foram avaliados clones individuais, por mais duas gerações. Foram realizadas simulações de diferentes intensidades de seleção de famílias na GS e PGC e intensidades de seleção de clones nas gerações seguintes. Os resultados indicam que intensidades de 50 e 60% produzem os maiores ganhos. As estimativas da h 2 em nível de famílias foram maiores que em nível de clones, o que confirma a eficiência da seleção de famílias em gerações precoces. A seleção de famílias para peso específico pode ser realizada em gerações precoces (GS e PGC), independentemente das condições de temperatura que será realizada a seleção clonal. A seleção sequencial de famílias, com intensidades de 60% (SG) e 60% (PGC), promoveria maior eficiência da seleção de clones na segunda e terceira geração clonal. No caso de aplicar intensidades mais fortes para aumentar a eficiência da seleção seque...

Comparison of BLUE and BLUP/REML in the selection of clones and families of potato (Solanum tuberosum)

“…Data to simulate the selection of clones and families, tuber yield, and tuber specific gravity were provided by Ticona-Benavente and Pinto (2012). These data comprised 30 clonal families originating from bi-parental crosses.…”

“…In the early selection of potato clonal families, it would be useful to assess a smaller number of clones with a higher likelihood of finding superior clones in the second clonal generation (Ticona-Benavente et al, 2011;Ticona-Benavente and Pinto, 2012). However, these gains per selection were slightly higher when utilizing BLUP in the FCG from 50 to 80% ( Figure 3A).…”

“…Selection of clones on FCG is not recommended because the heritability at the level of individual plants was shown to be 0.33 (Ticona-Benavente and Pinto, 2012). Therefore, one only needs to evaluate clones from the SCG, in which there are more plants per clone.…”

“…However, the strategy of selecting clonal families in early generations has been gaining importance since it enables the reduction of the amount of genotypes to be assessed in later clonal generations (Simmonds, 1996), thus increasing the probability of finding superior clones in superior families (Bradshaw et al, 2009;Ticona-Benavente and Pinto, 2012).…”

Efficiency of selection in early generations of potato families with a view toward heat tolerance

“…Therefore, early discard in the FCG would be eliminating families that in fact would not show good performance in the more advanced generation (SCG). Benavente and Pinto (2012) who worked with selection for tuber yield among potato families under high temperature conditions, found that selection intensities from 50% to 60% led to the best responses in clone selection.…”