Tag Archives: drought

433-438 A. M. Méndez, D. Castillo , A. del Pozo, I. Matus, R. Morcuende
Differences in Stem Soluble Carbohydrate Contents among Recombinant Chromosome Substitution Lines (RCSLs) of Barley under Drought in a Mediterranean–type Environment
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Differences in Stem Soluble Carbohydrate Contents among Recombinant Chromosome Substitution Lines (RCSLs) of Barley under Drought in a Mediterranean–type Environment

A. M. Méndez¹, D. Castillo² ³, A. del Pozo², I. Matus³, R. Morcuende¹

¹Institute of Natural Resources and Agrobiology of Salamanca, IRNASA–CSIC, Apartado 257, 37071 Salamanca, Spain; e–mail: rosa.morcuende@irnasa.csic.es
²Faculty of Agricultural Sciences, University of Talca, Casilla 747, Talca, Chile
³Instituto de Investigaciones Agropecuarias CRI-Quilamapu, Casilla 426, Chillán, Chile

Abstract:

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.

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433-438 T. Tammets
Estimation of extreme wet and dry days through moving totals in precipitation time series and some possibilities for their consideration in agrometeorological studies
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Estimation of extreme wet and dry days through moving totals in precipitation time series and some possibilities for their consideration in agrometeorological studies

T. Tammets

Estonian Meteorological and Hydrological Institute, Toompuiestee 24, 10149 Tallinn,Estonia; e-mail: t.taam@emhi.ee

Abstract:

Moving totals of daily precipitation are a more exact tool for indicating the most extreme weather periods and their frequency than monthly or 10-day precipitation totals. Therefore the terms ‘extreme wet’ and ‘extreme dry’ are used for the last day of a period of calculating the moving total of precipitation if that is larger or smaller than the specified limits. These terms qualify a day with extra wet or dry meteorological and surrounding conditions. The number of extreme days and limits that lead to a large yield loss vary by crops and phenological phases. Calculation of moving totals in precipitation long time series in any number of successive days allows presenting the dependence of the observed maximal and minimal amount of precipitation on the number of successive days in a period. Such dependence seems to be useful in estimating the climate resources in an area. Examples are given for Jõgeva, Pärnu and Ristna precipitation time series of 1957–2008.Estimation of extreme wet and dry weather conditions on the basis of moving totals ofdaily precipitation allowed distinguishing the most drastic periods and trends of the precipitation regime in Estonia in the last 50 years. A day is considered as extreme wet when the moving total of precipitation is at least 10 mm on 10 successive days leading up to this day. A day is considered as extreme dry when there was no precipitation during the successive 20 days till the observed day. By these criteria years with especially wet or dry periods are easily distinguished. Inter-annual variability of the average number of wet and dry days in Estonia increased notably in 1957–2006. The growing trend of annual total number of extreme (wet + dry) days is statistically significant.

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