In Ethiopia, although research on cotton improvement started as early as the mid 60`s, not much progress have been made to develop high yielding and quality fiber cotton varieties for production. Hence, the purpose of this work was to study the agronomic, yield and fiber quality performance of hybrid cotton varieties (YD-206, YD-203 and YD-211) along two local check varieties (Deltapine 90 and Stam 59A) for local registration and wider use. The experiment was carried out in a non-replicated single plot size of 10m x 10m across seven locations viz. Werer Agricultural Research Center, Amibara, Melkasedi, Gewane, Arbaminch, Shellie and Woyto. The results of this study indicated that, the three introduced hybrid cotton varieties gave higher seed cotton yield than the two local check varieties at all locations. Accordingly, the hybrid cotton varieties showed seed cotton yield advantage of 35.59% (YD-211), 35.54% (YD-206) and 29.43% (YD-223) over the best performed local check variety (Deltapine 90). Similarly lint yield and fiber length performances of the hybrids were superior to that of the local check varieties. Furthermore, agronomic and crop protection practices have to be determined to maximize production and productivity of these hybrids to ensure the profitability of the user and widen its acceptance.

Cotton varieties that are high yielding and resistant to pests are required to improve production and productivity and to capitalize on the crop’s enormous potential and its critical role in Ethiopia’s expanding textile industry. Lack of improved cotton technology has forced farmers to recycle local varieties for ages which have become very susceptible to pests which are the major causes of very low productivity and quality of cotton in the country. Among major pests, bollworms (Helicoverpa armigera and Pectinophora gossypiella) account for 36–60% of yield losses. In the absence of genetically resistant or tolerant varieties, genetically engineered bollworm-resistant Bacillus thuringiensis (Bt) cotton has offered a great opportunity to reduce crop losses from bollworms. The objective of the study was to evaluate the efficacy of bollworm resistance and adaptability of Bt cotton varieties across cotton growing environments in Ethiopia and provide recommendations. Two Bt cotton hybrids (JKCH 1947 and JKCH 1050), one Bt OPV (Sudan), and three OPV conventional varieties (Weyito 07, Stam-59A, and Deltapine-90) were evaluated at seven different agro-ecologies using a randomized complete block design (RCBD) with three replications. Results showed significant differences among genotypes for yield and other traits. Hybrids JKCH 1947 and JKCH 1050 were the top high yielders under high and mild bollworm infestations, with mean seed cotton yield of 3.10 t·ha−1 each and lint yield of 1.20 and 1.19 t·ha−1, respectively, whereas the standard check Deltapine-90 (popular variety) recorded a mean seed cotton and lint yield of 2.3 t·ha−1 and 0.8 t·ha−1, respectively. Combined analysis showed that genotypes, environment, and the genotypes × environment interactions had a highly significant effect ( P  < 0.05) on fiber quality. Weyito 07 and the two hybrids (JKCH 1947 and JKCH 1050) had upper half mean fiber lengths in the range of 27.78 to 32.11 mm. For fiber strength, genotypes Weyito 07, JKCH 1050, Stam-59A, and JKCH 1947 had 33.50 g/tex, 28.59 g/tex, 28.00 g/tex, and 27.75 g/tex, respectively. The fiber quality values of the hybrids were within acceptable limits, with staple lengths ranging from 27.78 to 28.44 mm and fiber strengths ranging from 27.75 to 28.59 g/tex. Results show potential adaptation of the hybrids under different cotton growing environments and their superior yield performance due also to added protection of yield losses from damage by bollworms. The contrast is bigger under high insect pressure conditions due to the genetically engineered Bt trait compared to the conventional varieties. The effective field resistance against bollworms in most locations shows that wider use of these hybrids can enhance cotton productivity and quality in Ethiopia.