Yield variation and aphid scoring of different cowpea (Vigna unguiculata) genotypes across the environment

Producing improved legume forages may contribute to the improvement of the quality supply of the livestock feeding system in Ethiopia. Dry matter and seed yield evaluation and aphid infestation scoring of cowpea genotypes were undertaken for three production seasons (2018-2019). The treatment of five cowpea accessions (ILRI_9333, ILRI_9334, ILRI_11114, ILRI_12668, and ILRI_12713) and one recently released variety as a standard check (Temesgen) at three locations (Arba Minch Agricultural Research Center (AMARC), Bonga Agricultural Research Center (BARC) and Hawassa Agricultural Research Center (HARC) was laid out at the field in a randomized complete block design with three replications. Growth, yield, and aphid scoring parameters were collected to present the comparison of genotypes. Vine length and branch number of ILRI_3334 followed by ILRI_12173 was significantly taller in all locations than the standard check and other genotypes in the test. Dry matter yield production was significantly (P<0.05) higher for ILRI_12713 (8.87 t/ha) followed by ILRI_9334 (8.44 t/ha) and ILRI_11114 (8.4 t/ha) while in seed yield variety ILRI_11114>ILRI_12668>ILRI_12713 than Temegen and others in the experiment. Aphid infestation in the cowpea field significantly influenced dry matter yield and seed yield. Dry matter yield was positively correlated with branch number and vine length. Seed yield was positively and significantly (P= 0.047 and 0.015) correlated with seed per pod and harvest index. Hence, ILRI_12713, ILRI_9334, and ILRI_11114 are to be considered for further cowpea breeding programs for dry matter and seed yield under aphid-infested conditions. Quality of the materials under irrigated and other agronomic conditions might be the future assignment.