Use of a water stress index to identify barley genotypes adapted to rainfed and irrigated conditions

• Published in: Crop science Vol. 44; no. 6; pp. 2127 - 2137
• Main Authors: Rizza, F, Badeck, F.W, Cattivelli, L, Lidestri, O, Di Fonzo, N, Stanca, A.M
• Format: Journal Article
• Language: English
• Published: Madison Crop Science Society of America 01.11.2004; American Society of Agronomy
• Subjects: Adaptability; Adaptation to environment and cultivation conditions; Agronomy. Soil science and plant productions; Barley; Biological and medical sciences; Climate change; Cultivars; Drought; dryland farming; Environmental risk; Evapotranspiration; Fundamental and applied biological sciences. Psychology; Genetics and breeding of economic plants; genotype; Genotype & phenotype; genotype-environment interaction; Genotypes; grain yield; Growing season; Hordeum vulgare; irrigated farming; plant development; plant stress; plant-water relations; Varietal selection. Specialized plant breeding, plant breeding aims; Water stress; water stress index; Italy; Southern Europe; Europe; Irrigation; Monocotyledones; Hordeum vulgare; Rainfed agriculture; Genotype; Water stress; Cereal crop; Genotype environment interaction; Gramineae; Drought resistance; Angiospermae; Spermatophyta; Yield; Mediterranean climate; Adaptation; Cultivar
• ISSN: 0011-183X; 1435-0653
• DOI: 10.2135/cropsci2004.2127

Future climate changes are expected to increase risks of drought, which already represent the most common stress factor for stable barley (Hordeum vulgare L.) production in Mediterranean areas. It is important, therefore, to evaluate if there are needs of specific adaptive measures in selecting genotypes for these more stressful environments. Our objective was to study diversity of yield performance under rainfed (R) and irrigated (I) conditions in 89 barley genotypes of different origin, growth habit, and year of release, representing a sample of cultivars grown in Europe. The experiment was conducted at Foggia (southern Italy) for 3 yr. For each trial, a water stress index (WSI) was calculated on the basis of the daily potential and actual evapotranspiration in the growing season, estimated by Thornthwaite's method. The WSI explained most of the variation in yield (R2 = 0.89**) among years and treatments. We examined, using the yield vs. WSI regression, the behavior of a given genotype across trials. The intercept and slope values were used as measures of yield potential and adaptability under drought, respectively. Several cultivars showing high yield potential and minimal genotype x environment (GE) interaction were identified. Notably, they were characterized by a high slope of the yield vs. WSI regression. Furthermore, within the range of water stress here examined, high yield potential played a preeminent role in the performance of these barley genotypes. This explains why, in this specific context, a selection based on minimum yield decrease under stress with respect to favorable conditions failed to identify the best genotypes.