Can partial reduction of shoot biomass during early vegetative phase of chickpea save subsoil water for reproductive and pod filling?

Abstract

The present study investigated if partial reduction of shoot dry matter during early vegetative growth phase of chickpea crop (cv. PBA Seamer) saves sub-soil water for reproductive growth and grain filling of the crop grown at 9 diverse environments. The environments were created by a combination of 3 sites (Emerald, Hermitage and Kingaroy), 3 planting windows (environments 1, 2, 3 at each site) with and without supplementary irrigation. The effects of environments on canopy management (partial reduction in shoot dry matter vs control) and irrigation treatments on the water uptake by roots, crop growth and yield performance and yield components were investigated. Crops in the planting windows (EN 1, 2, 3) experienced variable environments at each site. Days to 50% flowering and crop maturity reduced progressively from EN 1 to EN 3 at the three sites. The environment had significant effect on shoot biomass, yield and HI at the three sites (P < 0.01 or P < 0.0001). Environments had bigger effects on crop that partial reduction in shoot biomass (PRS). The PRS at early vegetative phase resulted in a 25% reduction in radiation intercepted but rapid compensatory growth that followed, resulted in minimal effect on shoot biomass and yield. The HI varied from 0.18 in EN 1 at Kingaroy to > 0.5 in EN 2 at Emerald. There was a trend for an increase in HI from EN 1 to EN 3 at all sites. The response to Irr, computed as the difference in peak shoot biomass and yield between the Irr and RF treatments, was the highest at Hermitage and the least at Emerald site. Vapour pressure deficit during reproductive phase accounted for the majority of variation in shoot biomass response to irrigation (r2 =0.66, P < 0.001) for total dry matter and (r2 =0.46, P < 0.01) for yield. The environments had a significant effect on radiation use efficiency and water use efficiency and the yield components including hundred seed weight.