Integrating molecular tools with conventional breeding strategies for improving phosphorus acquisition by legume crops in acid soils of Sub-Saharan Africa

Abstract

Leguminous crops are key components of low input agricultural cropping systems, and play an important role in ensuring food security in many societies in Sub-Saharan Africa (SSA). However, legume crop productivity in SSA is frequently limited by mineral nutrient deficiencies (particularly phosphorus, P). A common remedy for P deficiency is the application of P-fertilizers or in the case of low input cropping systems the reliance on symbiotic relations between crops and beneficial soil bacteria (rhizobia) and fungi (mycorrhizas). More recently, identification of legume species and genotypes with high efficiencies of P uptake and P use has been the focus of improvement programs using conventional breeding techniques. Due to inherent time limitations in conventional breeding approaches, progress in improving legume P uptake and P use efficiencies has been slow. Advances in attaining this goal could be by integrating molecular tools with conventional improvement strategies. A consideration of molecular and physiological mechanisms underlying differences in P uptake and P use efficiencies can result in more precise targeting of genetic variation and improvement through marker-assisted selection and other conventional techniques. This article discusses the potential for improving legume crop P uptake and P use efficiency in low-P, acid soils of SSA by integrating physiological and genomic tools, with conventional crop improvement in acid soils. Key words: Legume, phosphorus uptake, breeding, comparative genomics, crop improvement, Sub-Saharan Africa.