The search for commercial sweet white lupin (Lupinus albus L.) adaptive to Ethiopian growing condition seems not successful: what should be done?

Abstract The study was conducted to find new adaptive commercial sweet white lupin (Lupinus albus L.) varieties and evaluate the effect of inoculum on herbage and seed yields of white and blue lupin varieties in Ethiopia for two growing seasons in two locations. For the experiment a factorial arrangement (seven variety * two inoculation) in a randomized complete block design with three replication was used. Three sweet blue (Bora, Sanabor and Vitabor), three sweet white (Dieta, Energy and Feodora) and one bitter white local landrace lupin varieties were tested in the experiment. Analysis of variance was done using the general linear model procedure in SAS. The effects of location and inoculum were insignificant (P ≥ 0.0761) on yield and yield parameters. The effect of variety was observed (P ≤ 0.035) only on plant height, fresh biomass yield and thousand seed weight in both seasons except for fresh biomass yield in season two. However, its effect on other parameters was not shown (P ≥ 0.134) in both growing seasons or only shown in either season. The mean dry matter yield of all varieties was 2.45 ton per ha. However, sweet blue entries performed better than white entries. The mean seed yield of blue sweet lupin entries and white local check was 2.6 ton per ha. Sweet blue and white local landrace varieties were found tolerant while, commercial sweet white lupin varieties were susceptible for anthracnose and fusarium diseases that occurred immediately after flowering. As a result imported commercial sweet white varieties failed to give seed yield. Developing adaptive, disease resistant and high yielding sweet white lupin through crossing the local and commercial varieties and looking for species specific inoculum should be the future research agendas.