Wheat (Triticum aestivum L.) is the major crop in terms of planted area and presents the largest ... more Wheat (Triticum aestivum L.) is the major crop in terms of planted area and presents the largest distribution in the country covering a wide range of climatic regions. This study assesses the changes of various agronomic traits of winter wheat cultivars released in Chile between 1920 and 2000. A total of 117 winter accessions, representing 45 old and 72 modern cultivars were tested in a humid Mediterranean-type climate, with irrigation, in 2003. Old cultivars were those released before 1960 and modern ones were those released after 1960. Principal component (PC) analysis using 10 agronomic traits clearly separate modern from old cultivars of winter wheat. Comparing modern cultivars with old ones, plant height have been reduced by 25.6%, but others traits have increased, like harvest index (21.1%), number of grains per ear (42.6%), sedimentation value (103%), and grain hardness (32.0%). The variation in plant height was negatively correlated with harvest index (r =-0.30, p < 0.001...
Part of the Plant Sciences Commons This document is available at https://uknowledge.uky.edu/igc/2... more Part of the Plant Sciences Commons This document is available at https://uknowledge.uky.edu/igc/23/2-3-2/1 The XXIII International Grassland Congress (Sustainable use of Grassland Resources for Forage Production, Biodiversity and Environmental Protection) took place in New Delhi, India from November 20 through November 24, 2015. Proceedings Editors: M. M. Roy, D. R. Malaviya, V. K. Yadav, Tejveer Singh, R. P. Sah, D. Vijay, and A. Radhakrishna Published by Range Management Society of India
Changing climates and associated increased variability pose risks to alfalfa (Medicago sativa L.)... more Changing climates and associated increased variability pose risks to alfalfa (Medicago sativa L.) cultivation, with the requirement to establish, survive, and maintain production under water stress. Crop wild relatives (CWR) of alfalfa include populations that have evolved to survive in a number of different, extreme environments, but until recently have had limited use in breeding programs. Here we report on the phenotypic diversity of alfalfa crop wild relatives that were selected to represent extremes in drought tolerance (by sourcing germplasm from environments with extremes in low rainfall, high temperature, shallow soils, and winter freezing) with the aim of providing germplasm with drought tolerance and improved forage yield traits for breeding programs in both warm and cool dry temperate environments. Newly formed hybrids created between M. sativa, M. arborea L. (a woody shrub), and M. truncatula Gaertn. (an annual species from the Mediterranean region) were developed or acq...
Drought is one of the major abiotic stresses that dramatically threaten the global food supply an... more 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...
In Chile's Mediterranean region, over 18% of plant species are alien. This is particularly no... more In Chile's Mediterranean region, over 18% of plant species are alien. This is particularly noteworthy in some agrosilvopastoral systems such as the espinales, which are functionally very similar to the Spanish dehesas and are of great ecological and socioeconomic interest. In the present paper we analyse Chile's non-native flora, considering three scales of analysis: national, regional (the central region, presenting a Mediterranean climate) and at community level (the espinales within the central region). We compare this flora with that recorded in areas of the Iberian Peninsula with similar lithological and geomorphological characteristics, and land use. We discuss possible mechanisms that might have been operating in the floristic colonisation from the Mediterranean Basin to Chile's Mediterranean region.
In crop breeding, the interest of predicting the performance of candidate cultivars in the field ... more In crop breeding, the interest of predicting the performance of candidate cultivars in the field has increased due to recent advances in molecular breeding technologies. However, the complexity of the wheat genome presents some challenges for applying new technologies in molecular marker identification with next-generation sequencing. We applied genotyping-by-sequencing, a recently developed method to identify single-nucleotide polymorphisms, in the genomes of 384 wheat (Triticum aestivum) genotypes that were field tested under three different water regimes in Mediterranean climatic conditions: rain-fed only, mild water stress, and fully irrigated. We identified 102,324 single-nucleotide polymorphisms in these genotypes, and the phenotypic data were used to train and test genomic selection models intended to predict yield, thousand-kernel weight, number of kernels per spike, and heading date. Phenotypic data showed marked spatial variation. Therefore, different models were tested to...
Summary - We review and briefly analyse some of the main ecophysiologica1 attributes found in ann... more Summary - We review and briefly analyse some of the main ecophysiologica1 attributes found in annual legumes in evolutionary and ecological response to the environmental factors affecting their development, reproduction and and survival in Mediterraean Type Ecosystems. We also give some examples of inter-and intra- specific differences that need to be talcen into account when introducing or disseminating annual legumes for pasture improvement, rehabilitation efforts, erosion control and/or long term soil restoration programmes.
Wheat (Triticum aestivum L.) is the major crop in terms of planted area and presents the largest ... more Wheat (Triticum aestivum L.) is the major crop in terms of planted area and presents the largest distribution in the country covering a wide range of climatic regions. This study assesses the changes of various agronomic traits of winter wheat cultivars released in Chile between 1920 and 2000. A total of 117 winter accessions, representing 45 old and 72 modern cultivars were tested in a humid Mediterranean-type climate, with irrigation, in 2003. Old cultivars were those released before 1960 and modern ones were those released after 1960. Principal component (PC) analysis using 10 agronomic traits clearly separate modern from old cultivars of winter wheat. Comparing modern cultivars with old ones, plant height have been reduced by 25.6%, but others traits have increased, like harvest index (21.1%), number of grains per ear (42.6%), sedimentation value (103%), and grain hardness (32.0%). The variation in plant height was negatively correlated with harvest index (r =-0.30, p < 0.001...
Part of the Plant Sciences Commons This document is available at https://uknowledge.uky.edu/igc/2... more Part of the Plant Sciences Commons This document is available at https://uknowledge.uky.edu/igc/23/2-3-2/1 The XXIII International Grassland Congress (Sustainable use of Grassland Resources for Forage Production, Biodiversity and Environmental Protection) took place in New Delhi, India from November 20 through November 24, 2015. Proceedings Editors: M. M. Roy, D. R. Malaviya, V. K. Yadav, Tejveer Singh, R. P. Sah, D. Vijay, and A. Radhakrishna Published by Range Management Society of India
Changing climates and associated increased variability pose risks to alfalfa (Medicago sativa L.)... more Changing climates and associated increased variability pose risks to alfalfa (Medicago sativa L.) cultivation, with the requirement to establish, survive, and maintain production under water stress. Crop wild relatives (CWR) of alfalfa include populations that have evolved to survive in a number of different, extreme environments, but until recently have had limited use in breeding programs. Here we report on the phenotypic diversity of alfalfa crop wild relatives that were selected to represent extremes in drought tolerance (by sourcing germplasm from environments with extremes in low rainfall, high temperature, shallow soils, and winter freezing) with the aim of providing germplasm with drought tolerance and improved forage yield traits for breeding programs in both warm and cool dry temperate environments. Newly formed hybrids created between M. sativa, M. arborea L. (a woody shrub), and M. truncatula Gaertn. (an annual species from the Mediterranean region) were developed or acq...
Drought is one of the major abiotic stresses that dramatically threaten the global food supply an... more 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...
In Chile's Mediterranean region, over 18% of plant species are alien. This is particularly no... more In Chile's Mediterranean region, over 18% of plant species are alien. This is particularly noteworthy in some agrosilvopastoral systems such as the espinales, which are functionally very similar to the Spanish dehesas and are of great ecological and socioeconomic interest. In the present paper we analyse Chile's non-native flora, considering three scales of analysis: national, regional (the central region, presenting a Mediterranean climate) and at community level (the espinales within the central region). We compare this flora with that recorded in areas of the Iberian Peninsula with similar lithological and geomorphological characteristics, and land use. We discuss possible mechanisms that might have been operating in the floristic colonisation from the Mediterranean Basin to Chile's Mediterranean region.
In crop breeding, the interest of predicting the performance of candidate cultivars in the field ... more In crop breeding, the interest of predicting the performance of candidate cultivars in the field has increased due to recent advances in molecular breeding technologies. However, the complexity of the wheat genome presents some challenges for applying new technologies in molecular marker identification with next-generation sequencing. We applied genotyping-by-sequencing, a recently developed method to identify single-nucleotide polymorphisms, in the genomes of 384 wheat (Triticum aestivum) genotypes that were field tested under three different water regimes in Mediterranean climatic conditions: rain-fed only, mild water stress, and fully irrigated. We identified 102,324 single-nucleotide polymorphisms in these genotypes, and the phenotypic data were used to train and test genomic selection models intended to predict yield, thousand-kernel weight, number of kernels per spike, and heading date. Phenotypic data showed marked spatial variation. Therefore, different models were tested to...
Summary - We review and briefly analyse some of the main ecophysiologica1 attributes found in ann... more Summary - We review and briefly analyse some of the main ecophysiologica1 attributes found in annual legumes in evolutionary and ecological response to the environmental factors affecting their development, reproduction and and survival in Mediterraean Type Ecosystems. We also give some examples of inter-and intra- specific differences that need to be talcen into account when introducing or disseminating annual legumes for pasture improvement, rehabilitation efforts, erosion control and/or long term soil restoration programmes.
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Papers by Alejandro Del Pozo