EFFICIENCY OF SELECTION INDEXES TO IDENTI FY SUPERIOR CLONES OF POTATO

Most breeders, either analytically or intuitively, practice multiple t rait selection when developing cultivars. The objective of this paper was to evaluate the selection methods used to identify high yielding p otato (Solanum tuberosum L.) clones, with high percentage of large tub ers, good general tuber appearance and superior specific gravity. In L avras, State of Minas Gerais, Brazil, 817 experimental clones were eva luated by means of augmented block designs. Using either independent c ulling level or Elston (1963) indices allowed selection of clones with defined limits, but the population size was severely reduced possibly excluding genotypes with wide adaptation. Selection indices improved the distribution of genetic gains of important characters compared wit h direct selection for the same characters. Indices of Smith (1936), H azel (1943), Williams (1962), Pesek & Baker (1969) and Mulamba & Mock (1978) were indicated to be used in potato breeding programs making us e of the genetic standard deviations and or their reciprocals as econo mic weights.