Use of a Water Stress Index to Identify Barley Genotypes Adapted to Rainfed and Irrigated Conditions

Abstract

and, to some extent, conflicting mechanisms. Traits related to drought resistance, such as small plant size, re-Future climate changes are expected to increase risks of drought, duced leaf area, and early maturity, lead to reduced total which already represent the most common stress factor for stable seasonal evapotranspiration. Prolonged stomatal closure barley (Hordeum vulgare L.) production in Mediterranean areas. It is important, therefore, to evaluate if there are needs of specific allows plants to limit water loss but also reduces dry matter adaptive measures in selecting genotypes for these more stressful production (Karamanos and Papatheohari, 1999). These environments. Our objective was to study diversity of yield perfortraits, however, are associated with a lower yield potential mance under rainfed (R) and irrigated (I) conditions in 89 barley (Fischer and Wood, 1979). Furthermore, assimilate accugenotypes of different origin, growth habit, and year of release, repremulation in the stems before anthesis is advantageous if senting a sample of cultivars grown in Europe. The experiment was drought occurs during the following phases, but it could conducted at Foggia (southern Italy) for 3 yr. For each trial, a water reduce spike weight at anthesis (Slafer and Araus, 1998). stress index (WSI) was calculated on the basis of the daily potential Thus, traits related to drought resistance and to high and actual evapotranspiration in the growing season, estimated by yield potential should be alternatively favored in cereal Thornthwaite's method. The WSI explained most of the variation in breeding programs, based on the ideotype for a target yield (R 2 ϭ 0.89**) among years and treatments. We examined, using the yield vs. WSI regression, the behavior of a given genotype across area and a specific type of stress. According to some trials. The intercept and slope values were used as measures of yield authors, yield in low and high yielding environments potential and adaptability under drought, respectively. Several cultican be considered as separate traits which are not necesvars showing high yield potential and minimal genotype ϫ environsarily maximized by identical sets of alleles (Falconer, ment (GE) interaction were identified. Notably, they were character-1990), consequently plant breeding strategies should be ized by a high slope of the yield vs. WSI regression. Furthermore, different when targeting stress and nonstress environwithin the range of water stress here examined, high yield potential ments (Ceccarelli et al., 1991; Ceccarelli et al., 1998). played a preeminent role in the performance of these barley geno-

Multivariate analysis and drought stress tolerance indices in chickpea (Cicer arietinum L.) under different irrigation regimes

“…A positive correlation was reported between TOL and yield under normal condition (Yp) and a negative correlation was reported between TOL and yield under stress (Ys) (Table 4) suggest that selection based on TOL will results in reduced yield under well-watered conditions. Similar results were reported in several crops like wheat (Talebi et al, 2009), chickpea and barley (Rizza et al, 2004).…”

Conservation tillage in a semiarid Mediterranean environment: results of 20 years of research

“…Finally, following Rizza et al (2004), a crop water stress index (WSI) was calculated for each year and experimental site on the basis of the soil water balance to quantify the water stress experienced by the crop during its entire cycle, using the following formula: (2) where: n is the number of days of the wheat life cycle (from sowing to maturity); PET is the daily reference evapotranspiration estimated using the Hargreaves and Samani (1985) method; AET is the daily actual evapotranspiration, calculated as:…”

Strategies for Improving Water Productivity and Quality of Agricultural Crops in an Era of Climate Change

“…Rizza et al (2004) tested in rain/fed and irrigated conditions 89 barley genotypes representing a sample of the germplasm grown in Europe. Eight of them showed the best yield in both irrigated and rain-fed conditions.…”