Growth and nitrogen dynamics of spring chickpea genotypes in a Mediterranean-type climate

Chickpea (Cicer arietinum L.) is an important legume of rainfed farming systems, contributing to the sustainability of production and reducing the need for nitrogen (N) fertilization through fixing atmospheric N-2. The relative importance of factors causing variations in growth, seed yield, N accumulation and N utilization efficiency among spring chickpea varieties grown in a Mediterranean-type climate was investigated in field experiments conducted in 2003 and 2004. Five chickpea varieties were grown in a silty clay soil in the farm of the Democritus University of Thrace in Orestiada, Greece. Yearly differences in plant growth and productivity were observed and were mainly associated with the variations in the weather parameters between the growing seasons. Nitrogen utilization efficiency (NUE) for biomass production during the seed-filling period was higher compared with that during the vegetative period. NUE for seed yield (SY) ranged from 18.3 to 24.5 g dry matter (DM)/g N and was positively correlated with seed yield, suggesting that high SY was associated with more efficient exploitation of N. When the environmental conditions favoured high early N accumulation, the differences among varieties in NUE were mainly due to the differences in N partitioning at maturity, e.g. the nitrogen harvest index (NHI). The amount and the efficiency of N content at the beginning of seed growth (growth stage (GS) R5) that was translocated to the seed differed among varieties and ranged from 7.0 to 16.6 g N/m(2) and from 68.2 to 86.8 g DM/g N, respectively. Most of the variation (0.96) between varieties in N translocation could be accounted for by the differences in total N content at GS R5. N losses from the plant foliage between 0.61 and 9.92 g N/m(2) were detected during the seed-filling period when SY was low and N content at GS R5 was high.