Performance of cotton (Gossypium hirsutum L.) lines selected for high productivity in three environments

Three groups of cotton (Gossypium hirsutum L.) selections that had been screened in separate climatic zones within the San Joaquin Valley were tested for a 2-year period. Selection pressure had been applied solely upon productivity.Seven production attributes and eight fiber properties were influenced by the selection pressure on this material. The increase in number of bolls per m(2) virtually account for the genetic gains in yield.Environmental influences accounted for the larger part of the variability with both production and quality attributes. Years (seasons) and years x zone mean square values were highly significant for all production attributes except boll size. Fiber length was increased for one group of selections and decreased for the other two groups. Coarser fiber (micronaire increase) resulted from the selection effort with two groups.Genetic x environmental interactions encountered with major fiber properties have significant implications. The cryptic variability revealed indicates breeding procedures could be modified to exploit more fully the genetic potential of breeding material. Identifying and utilizing the "optimum selection enviroment" for specific attributes is suggested.