Development of elite medium staple cotton (G. Hirsutum) genotypes for production in middleveld upland ecologies

Ten (10) medium staple cotton genotypes comprising of five commercial varieties and five experimental lines were evaluated for field performance, genetic and environmental variability. The trials were laid out in a randomized complete block design (RCBD) with three replications. Analysis of variance was done for total seed cotton yield, lint yield, boll weight, earliness and gin out turn (GOT %) using Genstat 14th edition while stability and adaptability analysis was done using the AMMI model and the GGE biplot software. Significant differences (P<0.05) in genotype performances were observed in all the traits except for boll weight and earliness. The environment (E) effect was significant (P<0.05) for seed cotton yield and gin out-turn percentage (GOT %). The genotype (G) effect significantly (P<0.05) accounted for differences in boll weight and earliness index. The genetic x environment (GEI) interaction was not significant across the two seasons. SZ 9314 showed wide adaptation to all environments, a well-known and recommended characteristic of the commercial variety. These results show that 644-98-11, 917-05-7 and SZ-95-7 are promising genotypes that can be registered for production in upland cotton ecologies worldwide and they can be incorporated in future cotton improvement program. It is suggested that fibre quality traits for these experimental lines should be assessed.   Key words: Stability, genetic variation, environmental variability, environment interaction (GEI), additive main effect and multiplicative interaction (AMMI), genetic by environment (GGE), gin out turn (GOT %).