How diverse a farmer-managed wheat landrace can be?

Abstract

Phenotypic variation in phenological, quantitative and qualitative traits was assessed in geographically-isolated, farmer-managed wheat landrace populations grown under subsistence farming conditions. Several multivariate, genetic diversity and structural equation modeling procedures were used to build a comprehensive structure of the landrace and to (1) identify and construct multivariate distances between components of the landrace, (2) identify plant-and seed-related traits contributing to its composition, (3) build principal components that can account for maximum variation, (4) quantify variance components accounted for by major seed qualitative traits, (5) partition total diversity and estimate levels of population differentiation, (6) build and validate a predictive model of landrace population-trait association, (7) identify traits affecting spikelet fertility as a critical component of grain yield under the prevailing hot conditions in Oman, and (8) construct and interpret structural equation models to estimate the direct and indirect effects of quantitative and qualitative traits on grain yield per plant for each landrace population. The results will be discussed within the context of on-farm conservation and sustainable utilization of endangered wheat landrace populations under subsistence farming and to illustrate the use of advanced multivariate statistical methods in assessing phenotypic variation in subdivided landrace populations.

Unlocking the Patterns of the Tunisian Durum Wheat Landraces Genetic Structure Based on Phenotypic Characterization in Relation to Farmer’s Vernacular Name

“…Farmers' vernacular landraces name attribution, their seed maintenance, and their traditional agricultural practices are valuable information for gene bank management, conservation, and genetic diversity analysis studies [21,47]. Despite the overuse of homogenous, semi dwarf, and high yielding varieties, and the loss of durum wheat genetic diversity, nowadays looking for a new source of genetic variability from the existing collection of landraces became urgent to face the climate change and to moderate the high agricultural input systems.…”

“…Particularly, the Mediterranean landraces showed a higher level of polymorphism and allelic richness for some quality traits compared to those from Southwest Europe and Southwest Asia [14,15]. The West Mediterranean landraces have shown their resistance to drought [16,17] and diseases [18], their phenotypic plasticity and their adaptability to harsh environmental conditions, and low in-put farmers agro-systems [19][20][21]. However, these landraces including the Tunisian ones are continually lost, due to farmer's adoption of new high-yielding and homogenous cultivars released since the period of the Green Revolution in the 1970s, which resulted in narrowing the genetic diversity of durum wheat [10,22].…”

Unlocking the Patterns of the Tunisian Durum Wheat Landraces Genetic Structure Based on Phenotypic Characterization in Relation to Farmer’s Vernacular Name

“…Farmers´ vernacular landraces name attribution, their seed maintenance and their traditional agricultural practices are valuable information for gene bank management, conservation and genetic diversity analysis studies [21,48]. Despite the overuse of homogenous, semi dwarf and high yielding varieties, and the loss of durum wheat genetic diversity, nowadays looking for new source of genetic variability from the existing collection of landraces became urgent to face the climate change and to ovoid the high agricultural input systems.…”

“…Particularly, the Mediterranean landraces showed higher level of polymorphism and allelic richness for some quality traits compared to those from Southwest Europe and Southwest Asia [14,15]. The West Mediterranean landraces have shown their resistance to drought [16,17] and diseases [18], their phenotypic plasticity and their adaptability to harsh environmental conditions and low in-put farmers agro-systems [20,21]. However, these landraces including the Tunisian ones are continually lost, due to farmer's adoption of new high yielding and homogenous cultivars released since the period of the Green Revolution in 1970s, which resulted in narrowing the genetic diversity of durum wheat [10,22] .…”

Genetic variation of salt-stressed durum wheat ( Triticum turgidum subsp. durum Desf.) genotypes under field conditions and gynogenetic capacity

“…There is an increasing interest in the selection of stable and high-yielding genotypes to promote the salty water use efficiency in arid and semi-arid regions. Jaradat and Shahid [11] stated that wheat landraces are better adapted than modern cultivars to changing climate conditions. The performance of durum landraces may be attributed to their population genetic structure, buffering capacity, and combination of morpho-physiological traits conferring adaptability to stress environments.…”