Effects of transient subsurface waterlogging on root growth, plant biomass and yield of chickpea

Root growth and proliferation are important for achieving the yield potential of chickpea in soils prone to waterlogging. Root growth characteristics and seed yield of the desi cultivar Rupali and the kabuli cultivar Almaz that differ in seed size and early vigour were investigated under well-drained and transiently-waterlogged conditions in glass-walled root boxes in a controlled-temperature glasshouse. Rooting parameters and detailed measurements of root growth and proliferation were made at 2-day intervals using a root mapping technique and by sampling the roots from the soil 14 days after the transient waterlogging ended. Although the roots of the kabuli cultivar Almaz had greater dry matter and length than the desi cultivar Rupali, the subsurface waterlogging promptly stopped the root growth of both genotypes. Root dry matter in both types of chickpea was reduced by two-thirds, 14 days after the cessation of the 12-day waterlogging treatment. The reduction resulted from an inhibition in root growth and proliferation, which led to a lower root length density down the soil profile, particularly in the top 0.6Â m of the waterlogged plants. While root length and root dry matter was higher in the kabuli cultivar Almaz than in the desi cultivar Rupali after waterlogging, they were not associated with a greater above-ground dry matter or seed yield at maturity. The transient waterlogging reduced the seed yield by 54% in the kabuli cultivar Almaz and by 44% in the desi cultivar Rupali. The reduction in seed yield in the kabuli cultivar Almaz resulted from 50% decline in the number of seeds per pod while in the desi cultivar Rupali it was a consequence of less pods and seeds per pod. Subsurface waterlogging changed the rooting pattern in chickpea, inhibiting root branching and the growth of the tap root and severely reducing the growth of root branches. The release from the waterlogging induced the production of new roots rather than regrowth of existing roots.