Leaf area and crop growth in relation to phenology of barley in Mediterranean environments

Abstract

In a barley/livestock farming system of northern Syria, high biomass production in addition to high grain yield is desirable. The aim of this study was to assess the effect of environment and phenology on growth and yield of barley in northern Syria. Leaf area duration (LAD), specific leaf area (SLA), crop growth rate (CGR) on a thermal time basis, and biological and grain yields were compared for entries representing three contrasting development patterns: early heading spring types (pattern A), medium early heading winter types (pattern B), and late heading spring types (pattern C). The experiment was conducted in 1988/89 at two sites: Tel Hadya (TH, 250 mm precipitation) and Breda (BR, 180 mm). Cold damage occurred in winter and, especially at BR, drought stress developed in spring.

At the two sites, development was similar, but yields at TH were twice those at BR. This was related to a longer LAD and a faster CGR in spring. Development pattern affected growth. A long vegetative phase (pattern B) resulted in small leaves with a low SLA in winter, probably due to a slow leaf extension rate. Since cold tolerance and profuse tillering compensated for the small leaf size, pattern B had on average a longer LAD than pattern A. Pattern C had a longer LAD than pattern A because of a longer crop duration. This long duration had a negative effect on yield, so LAD was poorly related to yield. Development in spring was associated with CGR. Pattern C had a slow CGR and low yields; pattern B had the fastest CGR, but the yield advantage over pattern A was not significant. These results suggest that early heading winter barley, which combines long LAD with fast spring CGR, may give the best performance in a barley/livestock farming system in northern Syria.