Performances of biomass sorghum [Sorghum bicolor (L.) Moench] under different water regimes in Mediterranean region

Sorghum bicolor (L.) Moench is a multifunctional crop that can be successfully grown in areas where water supply is limited. The aim of this study was to evaluate sorghum genotypes for biomass performance and drought resistance in field conditions in Italy. Data from a survey conducted on 75 lines and two hybrids revealed that tropical sorghum landraces can achieve high yields (33-51 t ha(-1) under irrigation, and 20-29 t ha(-1) under rain-fed conditions) of total aboveground dry biomass. Performance under rain-fed conditions was significantly associated with green leaf area retention (r: -0.47; P: 0.001), plant height (r: 0.50; P: 0.001), and maturity (r: 0.61; P: 0.001). Differences in biomass production potential could explain the observed dry matter yield variability in sorghum materials under water stressed conditions. A stay-green source (SDS 1948-3) along with two senescent types (IS 23509 and IS 33350) were identified and could be of great interest in drought resistance breeding research. The need for developing drought tolerant sorghum hybrids in order to increase and stabilize biomass production is highlighted. (C) 2004 Elsevier B.V. All rights reserved.