Durum Wheat Landraces from East and West Regions of the Mediterranean Basin Are Genetically Distinct for Yield Components and Phenology

Abstract

Genetic diversity of durum wheat landraces is a powerful tool for the introgression of new alleles of commercial interest in breeding programs. In a previous study, our team structured a collection of 172 durum wheat landraces from 21 Mediterranean countries in four genetic populations related to their geographical origin: east Mediterranean (17), east Balkan and Turkey (23), west Balkan and Egypt (25), and West Mediterranean (73), leaving 34 genotypes as admixed, and association mapping was carried out for important agronomic traits. Using a subset of this collection, the current study identified 23 marker alleles with a differential frequency in landraces from east and west regions of the Mediterranean Basin, which affected important agronomic traits. Eastern landraces had higher frequencies than the western ones of alleles increasing the number of spikes (wPt-5385 on chromosome 1B), grains per m2 (wPt-0841 on chromosome 7B), and grain filling duration (7 significant marker trait associations). Eastern landraces had higher frequencies of marker alleles located on chromosomes 4A, 5B, and 6B associated with reduced cycle length, and lighter grains than the western ones. Also for lower kernel weight, four marker alleles were located on chromosome 1A. Breeders may use the molecular markers identified in the current study for improving yield under specific Mediterranean environments.

Unlocking the Genetic Diversity within A Middle-East Panel of Durum Wheat Landraces for Adaptation to Semi-arid Climate

“…To face the challenges of increasing wheat production under projected climate change, wheat breeding requires a comprehensive exploration of potential genetic resources and an in-depth understanding of their underlying environmental adaptations. The landrace gene pool harbors a wide genetic diversity that could be used to enrich the modern wheat genetic repertoire [2,11,[17][18][19]. In this study, field-based evaluations and molecular assays were integrated to evaluate and characterize yield-related traits in the core collection of durum wheat landraces from Southern Mediterranean semi-arid climates.…”

Screening for drought resistance during germination of modern and old Iberian wheat cultivars

“…Due to the vast number of ancient cultivars stored in germplasm banks, most are still to be agronomically characterized. Nonetheless, the use of ancient wheat cultivars in breeding programs may be useful when breeding for suboptimal environments such as those prevalent in the Mediterranean Basin (Soriano et al 2018). We believe that PEG experiments, such as the one described here, are suitable for screening drought tolerance prior to field trials.…”

“…Among the studied cultivars, Mestiço may be the least affected by any future growing reduction due to drought stress (Khayatnezhad and Gholamin 2011). Introgression of alleles from ancient cultivars, such Mestiço, into modern ones can be useful when breeding for suboptimal environments, such as those prevalent in the Mediterranean Basin (Soriano et al 2018). Furthermore, we propose future research into Rht genes able to maintain reduced height in modern cultivars without affecting early growth, such as Rht8 (Ellis et al 2004).…”

Morphological Characterization and Genetic Diversity Analysis of a Tunisian Durum Wheat (Triticum Turgidum Var. Durum) Collection

“…Five seeds from one spike of each accession were germinated and grown under controlled conditions with a photoperiod of 16h/24h, a hygrometry (RH) of 70% and a temperature of 20°C/16 °C (day/night rhythm) at Bioger research unit, INRAE France. At the seedling growth stage (Zadock scale [13][14], one leaf of each accession was sampled and placed in extraction plates. The plates were placed at (-80°C) for 12h before DNA extraction.…”

“…Therefore, the genetic and morpho-phenological characterization of landraces, sparsely cultivated under current farming system or stored in gene banks, would allow the identi cation of unexplored sources of diversity that may contain adaptation to several biotic and abiotic stresses [4,12,13]. The availability of landraces for breeding programs may also have particular relevance when breeding for suboptimal and marginal environments such as the Mediterranean Basin, where durum wheat and other crop species are largely cultivated under unstable and limited water conditions that cause considerable yield uctuations [14,15].…”