SELECTING STABLE AND HIGH-YIELDING SORGHUM CULTIVARS FOR THE SEMIARIDTROPICS

A sorghum breeding program was reactivated in 1981 and selected cultiv ars, along with local checks, were evaluated in two experiments in the sorghum growing region of northern Cameroon. Experiment 1 was conduct ed in the Extreme North Province where annual rainfall ranges from 450 to 850 mm. Experiment 2 was conducted in the North Province where ann ual rainfall exceeds 850 mm. The objective of the study was to select a high yield and high stability sorghum cultivar for each region. The cultivar's responses were investigated using two analyses: the adaptab ility analysis and the stability analysis. The former used the method of superiority measure, defined by distance mean square between the te st cultivar and the maximum (the highest yield in the location), and t he latter used type 4 stability parameter, defined by the years within location mean square averaged over all locations. The conceptual sepa ration of adaptability and stability facilitated the cultivars assessm ent. The results showed that in exp. 1, three cultivars S-35, CS-54 an d CS-61 had similar adaptability and stability, while in the exp. 2, S -34 was best in terms of yield but was unstable due to susceptibility to grain mold. In contrast, the second best cultivar CS-63 was poorer in the high-yielding environments but was more stable than S-34.