Evaluation of some Egyptian cotton genotypes over two stages

The present investigation deals with the variation among some Egyptian cotton (Gossypium barbadense L.) genotypes. They were evaluated within Giza 80 zone Minya and Beni Souf (Upper Egypt) through two programs (breeding and regional) during 2009 and 2010 seasons. A randomized complete block design was used in the two programs to estimate the variance among the genotypes. The first analysis used one observation per experimental unit to evaluate the genotypes in the first stage (individual generations or locations). The second analysis used more than one observation per experimental unit to evaluate genotypes in the second stage (two generations or locations). The results of the breeding program exhibited significant variation due to genotypes and hybrids vs. G80 were observed for total yields (seed and lint) and earliness. Hybrids significantly surpassed G80 with respect to total yields (seed and lint) and earliness except G90 x Pima S 62 (24240) (G83 x Pima S 6) x Dandara (G83 x (G75 x 5844)) x G85 and G91 x G80 for earliness in the two generations. The results of the analysis of two generations gave information with respect to variance between generations to be used in the breeding program. The results of the regional program showed that (G83 x (G75 x 5844)) x G80 gave the lowest values of variance between locations for boll weight and dry weight per boll in the first season harvest index in the second season and number of seeds per boll in the two seasons. G90 x Australian gave similar results for seed cotton yield and boll weight in 2009 season. Thus hybrids were more stable than G80. Results exhibited showed that G80 was more stable than hybrids for lint cotton yield in the two seasons due to its lowest variance between locations. The present study was very important in the two programs it selects the surpassed varieties in the breeding program replace new varieties to cultivars in the regional program and enter the statistical measure to evaluate the genotypes.