Diversity and Genetic Structure of a Collection of Spanish Durum Wheat Landraces

Abstract

Knowledge ofthe genetic structure of germplasm collections is crucial for conservation and efficient use of genetic resources. This study assessed the diversity and genetic structure of a collection of landraces of Spanish durum wheat {Triticum turgidum L.) using several marker systems and correlated the diversity and agromorphological traits with geographic and climatic features. Analyzed genotypes were separated into nine populations, with moderate to great genetic divergence among them. The three subspecies dicocoon, turgidum, and durum present in the collection largely determined the clustering of the populations. Genotype variation was lower in dicoccon and turgidum than in durum. Genetic differentiation by the agroecological zone of origin was greater in dicoocon and turgidum than in durum. Diversity arrays technology markers revealed two geographic substructures, east-west for diooccon and northeast-southwest for turgidum. The ssp. durum had a more complex structure, consisting of seven populations with high intrapopulation variation. Diversity arrays technology markers allowed the detection of subgroups within some populations, with agromorphological and gliadin differences, and distinct agroecological zones of origin. Two different phylogenetic groups were detected, revealing that some durum accessions were more related to ssp. turgidum from northern Spain while others seem to be more related to durum wheats from North Africa.

Wheat: A Crop in the Bottom of the Mediterranean Diet Pyramid

“…The results of the phylogenetic study showed that some durum accessions were more related to ssp. turgidum from northern Spain, while others were more related to durum wheats from North Africa [26]. These results also support the hypothesis of two possible forms of introduction of durum wheat in the Iberian Peninsula, South-East Europe and North Africa, as suggested by Moragues et al [17].…”

“…The irst diversity studies used phenotypic markers of morphological and physiological traits, but DNA-based markers are currently extensively used as they are not afected by the environment and can be detected in all tissues at all developmental stages. Among them, microsatellites or simple sequence repeats (SSRs) have proven to be very useful for evaluating the genetic diversity and population structure of Mediterranean wheat collections [17,[24][25][26][27][28][29].…”

“…A study was carried out by Ruiz et al [26] on a collection of 190 durum wheat Spanish landraces. The results showed that the diversity and agro-morphological traits were correlated with geographic and climatic features.…”

“…The accessions were grouped using molecular markers according to their geographical distribution-western and southern Europe, the eastern Mediterranean Basin, North Africa, Turkey, the Balkans and inally France-which was grouped with cultivars from central and northern European countries. The Spanish durum wheat core collection created by Ruiz et al [26] includes 94 accessions representative of a collection of 555 Spanish landraces and old cultivars and contains a wide range of genotypes adapted to Mediterranean environments.…”

Genetic Diversity and Association Mapping for Agromorphological and Grain Quality Traits of a Structured Collection of Durum Wheat Landraces Including subsp. durum, turgidum and diccocon

“…This was the case in Spain, whose durum wheat landraces have been classified into three main inter-fertile subspecies, dicoccon , turgidum , and durum , which all share the same AABB genomic constitution. Each subspecies had a different eco-geographical distribution and end use [15, 16]. Subspecies dicoccon (emmers), a hulled wheat for animal feed and bread making, represents a primitive stage in crop evolution, and was gradually replaced by more advanced free-threshing types of subsp.…”