APPLICATION OF CERTAIN SELECTION TECHNIQUES IN EVALUATING AND MAINTAINING EGYPTIAN COTTON VARIETIES

Abstract

A study was done in the Agronomy Department, Faculty of Agriculture, Kafr El-Sheikh, Tanta University.

The study was conceived in an effort to investigate:

(1) The genetic, phenotypic and environmental variances and covariances among some economic traits in two different population of Egyp1 ian cotton i.e. Giza 45 x Giza 85 cross and Giza 45 open-pollinated variety, (2) to estimate the magnitudes of the genotypic and phenotypic correlations between traits, (3) to compare the efficiencies of twelve selection indices constracted by formal statistical procedures, when the relative economic values of the three traits (Lint/plant, seeds/boll and lint/seed) are included combined with the two trait i.e. seed cotton yield/plant and earliness index and (4) to estimate the magnitudes of the genetic advances for all selection indices in earliness index from two populations. The investigations were carried out at Sakha Agricultural Research Farm and Laboratories, Sakha Agricultural Research Satiation, Egypt, ARC; during the 1997, 1998 and 1999 growing seasons.

Seven selection indices was applied in each population and 56 plants from F2 generation, having highest values for the characters seed cotton yield/plant, number of seeds/boll, lint/seed and earliness index in population I. (G.45 x G. 85) and 58 super plants from So in population II (G.45 open pollinated variety) were selected to form F3 and S 1 progenies, respectively. Selection in population I was continued through F3, and F4