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Mendez A.M.,CSIC - Institute of Natural Resources and Agriculture Biology of Salamanca | Castillo D.,University of Talca | Castillo D.,Institute Investigaciones Agropecuarias CRI Quilamapu | del Pozo A.,University of Talca | And 2 more authors.
Agronomy Research | Year: 2011

Drought is one of the major abiotic stresses that dramatically threaten the global food supply and it is becoming an increasingly severe problem in many regions of the world, mainly in Mediterranean areas and/or climates. This study investigates the effect of drought on the stem soluble carbohydrate content and its role in grain filling in different barley genotypes - four recombinant chromosome substitution lines (RCSLs) and the recurrent parent cv. Harrington, which had been growing in two contrasting Mediterranean environments in central Chile. At anthesis, drought stress increased the stem glucose and fructose contents in lines 76 and 78 and fructans in all the genotypes. At maturity, in non-stressed plants the soluble carbohydrate content in the stem decreased, suggesting a mobilization of carbohydrates from the stem into the grain. Drought increased the stem content of fructose, sucrose and fructans in all genotypes. The accumulation of fructans was higher in RCSLs as compared to Harrington, providing evidence that the introgression of the wild ancestor (Hordeum vulgare ssp. spontaneum) into cv. Harrington increases the terminal drought tolerance of barley. Line 89 showed the maximal content of fructans and it could be considered as the most tolerant to terminal drought of all RCSLs. However, this genotype showed the lowest grain weight and yield, indicating that is the most susceptible line of those referred to as grain yield.

Del Pozo A.,University of Talca | Castillo D.,University of Concepción | Castillo D.,Institute Investigaciones Agropecuarias CRI Quilamapu | Inostroza L.,Institute Investigaciones Agropecuarias CRI Quilamapu | And 3 more authors.
Annals of Applied Biology | Year: 2012

Physiological traits and productivity of the recombinant chromosome substitution lines (RCSLs) of barley, developed through the cross of Hordeum vulgare ssp. vulgare cv. Harrington and the wild ancestor Hordeum vulgare ssp. spontaneum, were measured in plants growing in microplots (with and without irrigation) and in field conditions in two Mediterranean-type environments, Cauquenes (rainfed) and Santa Rosa (irrigated). The objectives were to assess the degree of phenotypic variability in response to terminal drought stress and to test whether the introgression of the wild ancestor into cv. Harrington can increase the terminal drought tolerance of RCSLs of barley. Days from emergence to anthesis and from anthesis to maturity of the 80 RCSLs were reduced in only 2-4 days under water stress, in microplots. Specific leaf area (SLA) and stomatal conductance (gs) of 80 RCSLs and cv. Harrington decreased greatly under water stress in plants growing in microplots and field conditions (in 2004/05 growing season). No G × E interaction was detected except for SLA in the microplot experiment. The principal component analysis provided a clear distinction between RCSLs. Along the first principal component, it was possible to identify 24 RCSLs which represent the whole range of grain yield (GY), gs and SLA observed in the 80 RCSLs. The selected 24 RCSLs were evaluated in field conditions at Cauquenes and Santa Rosa, during two growing seasons (2007/08 and 2008/09). The gs and carbon isotope discrimination in grains (Δ 13C) were significantly (P < 0.001) lower in the rainfed condition (Cauquenes), but the water-soluble carbohydrates (WSC) in stems at anthesis and maturity was significantly (P < 0.001) higher than in well-irrigated condition (Santa Rosa). Grain yield was reduced by 63% under drought conditions. Differences between RCSLs in gs, WSC and GY were significant (P < 0.001) in 2007/08. The stress tolerance index (STI) was highly (P < 0.01) correlated with GY in all environments (rainfed and irrigated conditions and the two growing seasons). The relationship between STI and Δ 13C under rainfed condition allowed identifying drought tolerant and susceptible RCSLs; the former were high yielding lines under rainfed and irrigated conditions (and higher STI values), but with similar GY to cv. Harrington, but presented higher grain Δ 13C values than cv. Harrington. The drought susceptible lines presented lower GY, STI and Δ 13C values than cv. Harrington. These results suggest that H. spontaneum has contributed alleles that increase terminal drought tolerance to some of the RCSLs. © 2012 Association of Applied Biologists.

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