Modelling Biomass Accumulation and Partitioning in Chickpea (Cicer arietinum L.)

Quantitative information regarding biomass accumulation and partitioning in chickpea (Cicer arietinum L.) is limited or inconclusive. The objective of this study was to obtain baseline values for extinction coefficient (KS), radiation use efficiency (RUE, g MJ-1) and biomass partitioning coefficients of chickpea crops grown under well-watered conditions. The stability of these parameters during the crop life cycle and under different environmental and growth conditions, caused by season and sowing date and density, were also evaluated. Two field experiments, each with three sowing dates and four plant densities, were conducted during 2002-2004. Crop leaf area index, light interception and crop biomass were measured between emergence and maturity. A KS value of 0.5 was obtained. An average RUE of 1 g MJ-1 was obtained. Plant density had no effect on RUE, but some effects of temperature were detected. There was no effect of solar radiation or vapour pressure deficit on RUE when RUE values were corrected for the effect of temperature. RUE was constant during the whole crop cycle. A biphasic pattern was found for biomass partitioning between leaves and stems before first-seed stage. At lower levels of total dry matter, 54 % of biomass produced was allocated to leaves, but at higher levels of total dry matter, i.e. under favourable and prolonged conditions for vegetative growth, this portion decreased to 28 %. During the period from first-pod to first-seed, 60 % of biomass produced went to stems, 27 % to pods and 13 % to leaves. During the period from first-seed to maturity, 83 % of biomass was partitioned to pods. It was concluded that using fixed partitioning coefficients after first-seed are not as effective as they are before this stage. Environmental conditions (temperature and solar radiation) and plant density did not affect partitioning of biomass.