Breeding for water-logging tolerance in pigeonpea: current status and future prospects

Abstract Pigeonpea is grown in semi-arid tropics where the annual precipitation ranges from 200 to 800 mm and soil orders comprising of Inceptisols, Entisols, Alfisols, Vertisols, Mixed soils, and Aridisols. During monsoons, the semi-arid tropics also receive up to 140–180 mm/day rainfall for a span of 5–10 days, highlighting the chances of waterlogging in an early vegetative stage of pigeonpea, causing 25–30% yield loss in the Indian subcontinent. Waterlogging is a state where soil reaches saturation at submergence, creating an anaerobic condition in the root zone of the plants. As a result, plant withering, leaf chlorosis, stunted growth, lowered photosynthetic rate and plant mortality is evidenced widely. In response to waterlogging, the formation of aerenchyma cells, lenticels and adventitious roots were noticed as morphological adaptations. Whereas, the production of proline, peroxidase, superoxide dismutase, ethylene and alcohol dehydrogenase (ADH) as biochemical modifications. The minimal breeding efforts for waterlogging tolerance in pigeonpea may be the reason for the susceptibility of current varieties to waterlogging stress. This review emphasized the importance of breeding for waterlogging tolerance in pigeonpea. It focused on the morphological, physiological and biochemical adaptations of a plant when subjected to waterlogging stress. It accentuated the need for a standard screening protocol for waterlogging tolerance. Breeding strategies inclusive of novel single pod descent method, marker-assisted selection and rapid generation advancement techniques are discussed in detail.