Genotype x Environment Interactions for Oil Content in Cotton (Gossypium hirsutum L.) Cultivars Grown in Northern Cameroon

Abstract

Cotton breeding programs are mainly focus on improving fiber although the oil extracted from cotton seeds is the fifth vegetable oil consumed in the world due to its good quality. The purpose of this study was to evaluate six cultivars of Gossypium hirsutum regarding their oil content on four locations in the northern Cameroon during two consecutive seasons, in order to select stable genotypes for high oil content. In each location, the experimental design was a completely randomized block with three replications. The determination of the oil content of the cottonseeds was done by the Soxhlet method. Genotype x environment interaction (GEI) and analysis of stability of the varieties were determined by different methods using GEST 98 package. The variability among genotypes was high across environments for oil content (20.34% in Berem to 26.08% in Kourgui). The top ranked lines for oil were Irma Q302 (26.61%) and Irma A2249 (26.40%). This showed that there is genetic and environmental variability that can be exploited for the selection of genotypes at each site. The broad-sense heritability for oil content varied from 0.79 (Pitoa) to 0.83 (Berem) and expected genetic gain ranged from 14% to 23% with an overall average of 19%. Genotypes, environment and GEI effects were all significant and accounted respectively 35.65%, 43.41% and 20.93% of the total variation. Stability analysis identified high-yielding genotype Irma Q302 as specifically adapted to favourable environments of Kourgui and Pitoa.