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 ( < 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.

The present investigation was undertaken to study the extent of heterosis in respect of seed cotton and lint yield, fiber quality traits and other agronomic performances. Six cotton genotypes were crossed in all possible combinations including reciprocals. The resulting filial generation (F1 hybrids) seed of 30 crosses and 6 parents were planted in a simple lattice design with a perfect square of 6x6 replicated twice. Mean square due to genotypic differences were found significant for all the traits under study except for boll number per plant indicating the availability of substantial genetic diversity for different traits in the experimental materials. Among the hybrids intra specific G. hirsutum L. hybrid, HS-46 x Stonoville 453 19-8 X Stam 59A x Cucurova 1518 30-2 (B-1) exhibited considerable heterotic values for seed cotton and lint yield, and fiber length possibly suitable for local cottage and textile industries. The obtained results indicated the possibility of improving yield and fiber quality traits simultaneously using interspecific hybrids. Moreover, research on cotton breeding needs to address all possibilities including the exploitation of hybrid vigour to increase yield and fiber qualities of cotton production in Ethiopia.

Due to inadequate germination, emergence, and seedling stand establishment of inbred lines, hybrid seed multiplication results in poor performance and nonuniform seedlings in the field. Therefore, to assess the effect of various seed priming methods on maize inbred line seed germination measures, a laboratory experiment with 22 treatments in a completely randomized design with four replications was carried out in a controlled environment of Ambo Seed Quality Control Laboratory, Oromia Agricultural Input and Product Regulatory Authority. The treatment consisted of seeds that were hormone‐primed in gibberellic acid (GA₃) at levels of 100, 200, and 300 ppm; haloprimed in ZnSO₄ at levels of 1%, 2%, and 3%; and hydroprimed in distilled water for 12, 24, and 36 h. As a control, unprimed seeds were utilized. The study revealed that priming agent, duration, and their interactions had a significant (p < 0.5) effect on the examined seed germination metrics. The maximum germination percentages (96.5% and 96.25%) were recorded from seeds primed with 2% ZnSO₄ for 24 and 12 h, which improved by 11.56% and 11.27%, respectively. Priming the inbred line seed with GA₃ at 200 ppm for 36 h improves germination index and vigor index I and reduces mean germination time. Seeds primed with 3% ZnSO₄ and GA₃ at 200 ppm for 36 h gave the maximum root length (15.31 cm) and shoot length (13.50 cm), respectively, compared to the control treatment. Therefore, to improve the germination problem of the maize inbred line, it is advised seed producers to use a 2% ZnSO₄ solution for 24 h. However, if ZnSO₄ and GA₃ are not available, hydropriming for 36 h is more cost‐effective, produces less waste, and is easier to implement.