Although sorghum [Sorghum bicolor (L.) Moench] in West Africa (WA) is generally cultivated with limited or no fertilization on soils of low phosphorus availability, no assessments of the genetic variation among WA sorghum varieties for adaptation to low soil P are known. We assessed grain yields of 70 diverse sorghum genotypes under −P (no P fertilization) and +P conditions at two locations in Mali over 5 yr. Genetic variation for grain yield under −P conditions and the feasibility and necessity of sorghum varietal testing for grain yield under −P conditions were evaluated. Delayed heading dates (0–9.8 d) and reductions of grain yield (2–59%) and plant height (13–107 cm) were observed in −P relative to the +P trials. High estimates of genetic variance and broad-sense heritabilities were found for grain yield across both −P (h2 = 0.93) and +P (h2 = 0.92) environments. The genetic correlation for grain yield performance between −P and +P conditions was high (rG = 0.89), suggesting that WA sorghum varieties generally possess good adaptation to low-P conditions. However, genotype × phosphorus crossover interaction was observed between some of the highest yielding genotypes from the −P and +P selected sets, with the variety IS 15401 showing specific adaptation to −P. Direct selection for grain yield in −P conditions was predicted to be 12% more efficient than indirect selection in +P conditions. Thus, selection under −P conditions should be useful for sorghum improvement in WA.
Leiser, W.L.; Rattunde, H.F.W.; Piepho, H.P.; Weltzien, E.; Diallo, A.; Melchinger, A.E.; Parzies, H.K.; Haussmann, B.I.G. Selection Strategy for Sorghum Targeting Phosphorus-limited Environments in West Africa: Analysis of Multi-environment Experiments. Crop Science (2012) 52 (6) 2517-2527. [DOI: 10.2135/cropsci2012.02.0139]