Variation for carbon isotope ratio in a set of emmer (Triticum dicoccum Schrank) and bread wheat (Triticum aestivum L.) accessions

A high level of drought tolerance is an important objective in breeding new generation wheat varieties. A group of six landraces of the emmer wheat (Triticum diccocum Schrank), as well as two landraces, two old cultivars and two modern varieties of bread wheat (Triticum aestivum L.) were evaluated for their ability to discriminate 13C, a trait related to stomatal closure and consequently, an important component tolerance to drought. Three emmer wheat landraces and one of the bread wheat landraces has the lowest. Therefore, emmer wheat may play the role of a donor of the tolerance to drought in wheat breeding programs targetting drought prone conditions.Key words: Emmer wheat, bread wheat, drought tolerance, carbon isotope ratio, discrimination

Evaluación de la diversidad génetica en alforfón de Tartaria y trigo sarraceno

Genetic diversity of plant genetic resources for food and agriculture is a unique and irreplaceable source for further crop genetic improvement. The aim of this paper was the field evaluation of buckwheat genetic resources in the Czech Republic. In the case of the 77 common buckwheat (Fagopyrum esculentum Moench.) genotypes, most had reddishgreen stems (80%), cordate leaves (82%), white flowers (87%), and grey ovate achenes (44% and 57%, respectively). Vegetative growth duration ranged from 104 to 131 days. The 1000 seed weight (TSW) varied from 18.6 to 33.2 g. In the 15 tartary buckwheat (Fagopyrum tataricum Gaertn.) genotypes, there were no remarkable differences in morphological traits. Vegetative growth duration was 101 to 148 days, and the TSW varied from 8.10 to 20.0 g. Similarity/dissimilarity dendograms were calculated using the results of the field evaluation. Principal component analysis was also performed. The dendrograms showed high diversity in the morphological and phenological characteristics evaluated. Performance of the buckwheat varieties, particularly, their developmental stages, depended highly on the weather conditions of the year. Only days to flowering seemed to be affected by variety. Because the evaluation was made according to the IPGRI buckwheat descriptors the characteristics are compatible with data from other gene banks.Para la mejora vegetal es imprescindible disponer de diversidad genética en los recursos fitogenéticos para la alimentación y la agricultura. El objetivo de este estudio fue la evaluación en campo de la morfología y fenología de 77 accesiones de alforfón de Tartaria (Fagopyrum tataricum Gaertn.) y 15 de trigo sarraceno (Fagopyrum esculentum Moench.) en las condiciones de Europa Central, en la República Checa. La mayoría de los genotipos del trigo sarraceno poseen pedúnculos de color rojo-verde (80%), hojas acorazonadas (82%), flores blancas (87%) y semillas de color gris y oblongas (44% y 57%, respectivamente); el ciclo vegetativo oscila entre 104 y 131 días y el peso de mil semillas (TSW) entre 18,6 y 33,2 g. En el caso del alforfón de Tartaria no se detectaron diferencias significativas en los caracteres morfológicos; el ciclo vegetativo oscila entre 101 y 148 días; y el TSW entre 8,10 y 20,0 g. En base a estos resultados se creó un dendrograma de similitud y disimilitud generado por un análisis de componentes principales. El dendrograma indica una gran diversidad en las características morfológicas y fenológicas. Las fases de desarrollo dependieron principalmente de las condiciones climáticas del año en variedades de trigo sarraceno. Solo el carácter "días hasta floración" parece afectado por la variedad. Debido a que la evaluación se hizo de acuerdo con los descriptores para trigo sarraceno del IPGRI, los resultados son compatibles con los datos de otros bancos de germoplasma

Assessment of genetic diversity of selected tartary and common buckwheat accessions

Genetic diversity of plant genetic resources for food and agriculture is a unique and irreplaceable source for further crop genetic improvement. The aim of this paper was the field evaluation of buckwheat genetic resources in the Czech Republic. In the case of the 77 common buckwheat (Fagopyrum esculentum Moench.) genotypes, most had reddishgreen stems (80%), cordate leaves (82%), white flowers (87%), and grey ovate achenes (44% and 57%, respectively). Vegetative growth duration ranged from 104 to 131 days. The 1000 seed weight (TSW) varied from 18.6 to 33.2 g. In the 15 tartary buckwheat (Fagopyrum tataricum Gaertn.) genotypes, there were no remarkable differences in morphological traits. Vegetative growth duration was 101 to 148 days, and the TSW varied from 8.10 to 20.0 g. Similarity/dissimilarity dendograms were calculated using the results of the field evaluation. Principal component analysis was also performed. The dendrograms showed high diversity in the morphological and phenological characteristics evaluated. Performance of the buckwheat varieties, particularly, their developmental stages, depended highly on the weather conditions of the year. Only days to flowering seemed to be affected by variety. Because the evaluation was made according to the IPGRI buckwheat descriptors the characteristics are compatible with data from other gene banks.Para la mejora vegetal es imprescindible disponer de diversidad genética en los recursos fitogenéticos para la alimentación y la agricultura. El objetivo de este estudio fue la evaluación en campo de la morfología y fenología de 77 accesiones de alforfón de Tartaria (Fagopyrum tataricum Gaertn.) y 15 de trigo sarraceno (Fagopyrum esculentum Moench.) en las condiciones de Europa Central, en la República Checa. La mayoría de los genotipos del trigo sarraceno poseen pedúnculos de color rojo-verde (80%), hojas acorazonadas (82%), flores blancas (87%) y semillas de color gris y oblongas (44% y 57%, respectivamente); el ciclo vegetativo oscila entre 104 y 131 días y el peso de mil semillas (TSW) entre 18,6 y 33,2 g. En el caso del alforfón de Tartaria no se detectaron diferencias significativas en los caracteres morfológicos; el ciclo vegetativo oscila entre 101 y 148 días; y el TSW entre 8,10 y 20,0 g. En base a estos resultados se creó un dendrograma de similitud y disimilitud generado por un análisis de componentes principales. El dendrograma indica una gran diversidad en las características morfológicas y fenológicas. Las fases de desarrollo dependieron principalmente de las condiciones climáticas del año en variedades de trigo sarraceno. Solo el carácter «días hasta floración» parece afectado por la variedad. Debido a que la evaluación se hizo de acuerdo con los descriptores para trigo sarraceno del IPGRI, los resultados son compatibles con los datos de otros bancos de germoplasma

SSR allelic diversity changes in 480 European bread wheat varieties released from 1840 to 2000

A sample of 480 bread wheat varieties originating from 15 European geographical areas and released from 1840 to 2000 were analysed with a set of 39 microsatellite markers. The total number of alleles ranged from 4 to 40, with an average of 16.4 alleles per locus. When seven successive periods of release were considered, the total number of alleles was quite stable until the 1960s, from which time it regularly decreased. Clustering analysis on Nei's distance matrix between these seven temporal groups showed a clear separation between groups of varieties registered before and after 1970. Analysis of qualitative variation over time in allelic composition of the accessions indicated that, on average, the more recent the European varieties, the more similar they were to each other. However, European accessions appear to be more differentiated as a function of their geographical origin than of their registration period. On average, western European countries (France, The Netherlands, Great Britain, Belgium) displayed a lower number of alleles than southeastern European countries (former Yugoslavia, Greece, Bulgaria, Romania, Hungary) and than the Mediterranean area (Italy, Spain and Portugal), which had a higher number. A hierarchical tree on Nei's distance matrix between the 15 geographical groups of accessions exhibited clear opposition between the geographical areas north and south of the arc formed by the Alps and the Carpathian mountains. These results suggest that diversity in European wheat accessions is not randomly distributed but can be explained both by temporal and geographical variation trends linked to breeding practices and agriculture policies in different countries

Drought tolerance of land races of emmer wheat in comparison to soft wheat

As water deficiency becomes a more frequent cause of the reduction in wheat yield levels, the search for donors of drought tolerance to be bred into adapted land races becomes urgent. Drought tolerance has been evaluated by the 13 C discrimination method in six land races of emmer wheat ( Triticum dicoccum SCHRANK), compared with land races, obsolete cultivars and modern varieties of soft wheat ( Triticum aestivum L.). The results of a two-year trial show that most of the genetic resources of emmer wheat, and intermediate land races of wheat are predisposed to drought tolerance. These varieties respond to dry conditions more sensitively, as they close their pores earlier (a lower value of the discrimination of 13 C isotope). As for other land races and the top modern varieties of soft wheat, they are not thought to be predisposed to drought tolerance and their crop stands are liable to serious damage