Suchergebnisse

Trabajo presentado en el III Spanish Symposium on Physiology and Breeding of Cereals (III Simposio Español de Fisiología y Mejora de Cereales, SEFiMeC), celebrado online el 17 y 18 de noviembre de 2020. ; During the last years a wealth of genomic data regarding many plant species have been generated taking advance of the decline of the cost of sequencing, creating many new opportunities. However, at the same time, phenotyping has become the main bottleneck in plant breeding and fundamental plant science. This is particularly true for the assessment of plant diseases where, in addition to the time consuming evaluations, we have often to deal with the subjectivity of macroscopic visual assessments. In this work, we have developed an open script for semi-automated evaluation of rust disease. The script function under the free image software Fiji (developed from Image J), which is a well-recognized software among scientific community. The script allow the counting of the number of pustules in leaf segments by a color transformation tool, and provides three different automation modes. The script opens images sequentially and records infection frequency (pustules per area) (semi-)automatically for high-throughput analysis. Furthermore, it can manage several scanned leaf segments in the same image, consecutively selecting the desired segments. The script has been validated with nearly 900 samples from 80 oat genotypes ranging from resistant to susceptible and from very light to heavily infected leaves showing a high accuracy with a Lin's concordance correlation coefficient of 0.99. The analysis show a high repeatability as indicated by the low variation coefficients obtained when repeating the measurement of the same samples. The script also has optional steps for calibration and training to ensure accuracy, even in low-resolution images. This script can evaluate efficiently hundreds of leaves facilitating the screening of novel sources of resistance to this important cereal disease. ; This work was supported by the Spanish Ministry of Science and Innovation [PID2019-104518RB-I00], and regional government through the AGR-253 group.

Drought tolerance is a complex phenomenon comprising many physiological, biochemical and morphological changes at both aerial and below ground levels. We aim to reveal changes on root morphology that promote drought tolerance in oat in both seedling and adult plants. To this aim, we employed two oat genotypes, previously characterized as susceptible and tolerant to drought. Root phenotyping was carried out on young plants grown either in pots or in rhizotrons under controlled environments, and on adult plants grown in big containers under field conditions. Overall, the tolerant genotype showed an increased root length, branching rate, root surface, and length of fine roots, while coarse to fine ratio decreased as compared with the susceptible genotype. We also observed a high and significant correlation between various morphological root traits within and between experiments, identifying several of them as appropriate markers to identify drought tolerant oat genotypes. Stimulation of fine root growth was one of the most prominent responses to cope with gradual soil water depletion, in both seedlings and adult plants. Although seedling experiments did not exactly match the response of adult plants, they were similarly informative for discriminating between tolerant and susceptible genotypes. This might contribute to easier and faster phenotyping of large amount of plants. ; This work was supported by the Spanish Ministry of Economy and Competitiveness [AGL2016-78965AGR], (AEI/FEDER, UE) and regional government through the AGR-253 group, the European Regional and Social Development Funds and the COST action FA1306. FC is holder of a FPI fellowship from the Spanish Ministry of Economy and Competitiveness. ; Peer reviewed

Trabajo presentado en el IV Symposium on Physiology and Breeding of Cereals, celebrado en Pamplona el 16 y 17 de diciembre de 2021. ; In this study, we investigated the efficiency of genomic prediction and training set optimization in a highly structured population of cultivars and landraces of cultivated oat (Avena sativa) from the Mediterranean basin, including white (subsp. sativa) and red (subsp. byzantina) oats, genotyped using genotype-by- sequencing markers and evaluated for agronomic traits in Southern Spain. For most traits, the predictive abilities were moderate to high with little differences between models, except for biomass for which Bayes-B showed a substantial gain compared to other models. The consistency between the structure of the training population and the population to be predicted was key to the predictive ability of genomic predictions. The predictive ability of inter-subspecies predictions was indeed much lower than that of intra-subspecies predictions for all traits. Regarding training set optimization, the linear mixed model optimization criteria (prediction error variance (PEVmean) and coefficient of determination (CDmean)) performed better than the heuristic approach "partitioning around medoids," even under high population structure. The superiority of CDmean and PEVmean could be explained by their ability to adapt the representation of each genetic group according to those represented in the population to be predicted. These results represent an important step towards the implementation of genomic prediction in oat breeding programs and address important issues faced by the genomic prediction community regarding population structure and training set optimization. ; This work was supported by the Spanish Ministry of Science and Innovation [PID2019-104518RB-I00], and regional government through the AGR-253 group.

Trabajo presentado en el III Spanish Symposium on Physiology and Breeding of Cereals (III Simposio Español de Fisiología y Mejora de Cereales), celebrado online el 17 y 18 de noviembre de 2020. ; Drought tolerance is a complex phenomenon comprising many physiological, biochemical and morphological changes at both aerial and below ground levels. In this work, we explore the strategy of two oat cultivars to cope with drought, over an imposed water deficit time course of 20 days, based on root morphological, anatomical, physiological and molecular studies. We observed that the susceptible genotype increased dramatically the abscisic acid, at a relative soil water content as high as 60% resulting in a reduction of stomatal conductance. Despite this, leaf water potential decreased simultaneously due to a decrease in root hydraulic conductivity (conductivity per root length) in this genotype that showed early drought symptoms. By contrast, the resistant genotype, showed a mild and slow increase in abscisic acid that allowed maintaining transpiration longer. This was associated with an increase in root hydraulic conductivity together with root architectural changes such as an increase in total root length and in the length of the thinnest roots. In addition, root anatomical changes facilitated hydraulic transport and a reduction of metabolic cost. This strategy allowed the resistance genotype to maintain higher water potential reducing drought symptoms and promoting growth under water deficit conditions. ; This work was supported by the Spanish Ministry of Science and Innovation [PID2019-104518RB-I00], and regional government through the AGR-253 group.

[Key message] Genomic analysis of Mediterranean oats reveals high genetic diversity and three loci for adaptation to this environment. This information together with phenotyping and passport data, gathered in an interactive map, will be a vital resource for oat genetic improvement. ; [Abstract] During the twentieth century, oat landraces have increasingly been replaced by modern cultivars, resulting in loss of genetic diversity. However, landraces have considerable potential to improve disease and abiotic stress tolerance and may outperform cultivars under low input systems. In this work, we assembled a panel of 669 oat landraces from Mediterranean rim and 40 cultivated oat varieties and performed the first large-scale population genetic analysis of both red and white oat types of Mediterranean origin. We created a public database associated with an interactive map to visualize information for each accession. The oat collection was genotyped with 17,288 single-nucleotide polymorphism (SNP) loci to evaluate population structure and linkage disequilibrium (LD); to perform a genome-wide association study (GWAs) for heading date, a key character closely correlated with performance in this drought-prone area. Population genetic analysis using both structure and PCA distinguished two main groups composed of the red and white oats, respectively. The white oat group was further divided into two subgroups. LD decay was slower within white lines in linkage groups Mrg01, 02, 04, 12, 13, 15, 23, 33, whereas it was slower within red lines in Mrg03, 05, 06, 11, 21, 24, and 28. Association analysis showed several significant markers associated with heading date on linkage group Mrg13 in white oats and on Mrg01 and Mrg08 in red oats. ; This work was supported by the Spanish Ministry of Science and Innovation [AGL2016-78965AGR, PID2019-104518RB-100], (AEI/FEDER, UE) and regional government through the AGR-253 group, the European Regional and Social Development Funds, and Mobility Grant (FPI) 2018 from Ministry of Economy and Competitiveness of the Government of Spain [EEBB-I-18–12824]. FJC is holder of a FPI fellowship from the Spanish Ministry of Economy and Competitiveness [BES-2014–071044]. TL and CJH were supported by BBSRC grant BBS/E/W/0012843B. ; Peer reviewed