Phosphorus uptake and use efficiency of diverse West and Central African sorghum genotypes under field conditions in Mali

Sorghum [Sorghum bicolor (L.) Moench], a staple crop in West and Central Africa (WCA), is mostly cultivated on soils with low phosphorus (P) availability and thus adaptation to those conditions is vital for food security. Assessment of genotypic variation of WCA sorghum for P uptake and P use efficiency is undertaken to understand the diversity available and opportunities for its use. We assessed mature plant yield, P uptake and P use efficiency traits of 70 diverse WCA sorghum genotypes under -P (no P fertilization) and + P field conditions in Mali in 2010, to discover differences among all genotypes tested and between and within specific genotype groups. Large significant genotypic variation for P uptake and P use efficiency traits were observed for all genotypes among and within landrace and researcher bred pools under -P conditions. P uptake traits had a larger genotypic variation than P use efficiency traits. Landrace genotypes showed generally higher P uptake and grain P concentration while formally bred genotypes exhibited a higher P use efficiency. Photoperiod sensitivity was related to higher P uptake. Genotypic selection for P uptake and P use efficiency traits to improve adaptation to low P soils is possible in sorghum. Use and further study of WCA sorghums for adaptation to low P availability is appropriate as this germplasm shows large variation for P uptake and use efficiency and higher levels of P use efficiency than other important cereals.