Barley adaptation and improvement in the Mediterranean basin

Abstract

To study barley adaptation and improvement in the Mediterranean basin, a collection of 188 entries comprising landraces and old genotypes and current modern varieties from the Mediterranean basin and elsewhere was tested on moisture-contrasted environments in seven Mediterranean countries, during 2004 and 2005 harvest seasons. The experimental design consisted of an unreplicated trial for all entries, augmented by four repeated checks to which a partial replicate containing a quarter of the entries was added. Best Linear Unbiased Predictions (BLUPs) representing adjusted genotypic means were generated for individual trials using a mixed model. BLUPs were used for genotype by environment interaction analysis using main effect plus genotype by environment interaction (GGE) biplots of yield ranked data and for comparisons of landraces, old and modern genotypes using analysis of variance. Mean yields ranged from near crop failure to 6 t/ha. Local landraces were better adapted to environments yielding below 2 t/ha, thus breeding has mostly benefited environments yielding above 2 t/ha where modern genotypes out yielded landraces and old cultivars by 15%. Current barley selection is leading to specifically adapted genotypes.

Changes in allele frequencies in landraces, old and modern barley cultivars of marker loci close to QTL for grain yield under high and low input conditions

“…The general pattern of genotype adaptation, determined by the relative performance of the different genotypes in individual trials, coincided with many reports such as those by Ceccarelli (1996a) and Pswarayi et al (2008). Landraces were particularly adapted to low yield potential environments while cultivars adapted best to high yielding trials (Fig.…”

“…Studies of barley adaptation to drought conditions confirmed the loss of drought tolerance due to breeding and selection, as reported by Forster et al (2000). Many results from adaptation studies have shown that landraces were better adapted to stress environments, while modern genotypes were better adapted to stress-free, high yielding environments (Ceccarelli 1996a;Pswarayi et al 2008). Landraces could be used as a source of genes for adaptation to low yielding environments characterised by drought stresses, limited moisture availability, low fertility, and other related factors.…”

“…This fact suggest that modern cultivars are not always directly suitable to low input systems and point to their need for inputs in order to achieve high yields as reported by Ceccarelli (1996b). In fact, modern cultivars have been observed to be generally out yielded by local landraces in trials with mean yields below 2 t/ha in a wide collection of Mediterranean environments (Pswarayi et al 2008). The number [16 (low yield potential environments), 12 (high yield potential environments)] and magnitude of explained genotypic variation of significant QTL (R 2 up to 10% for low and high yield potential environments) were comparable for low and high input conditions.…”

Path analysis of genotype × environment interactions in rainfed durum wheat

“…This supports this idea that positive genetic gains in breeding programs more limited in environments with more stresses. This agrees with the findings of Ceccarelli (1996), Munoz et al (1998Munoz et al ( ), donmez et al (2001, Voltas et al (2002) and Pswarayi et al (2008). however, achieving genetic gains in yield in stressful environments has been recognized to be a difficult challenge for plant breeders, while progress in yield gains has been much higher in non-stressed environments (Richards et al, 2002;Villegas et al, 2007).…”

How to Make a Barranco: Modeling Erosion and Land-Use in Mediterranean Landscapes

“…Previously used-and-relinquished fields are available for reuse in the future. Farming returns are calculated per-plot by the average of three regression formulas, each calculated from empirical data about the effect of soil depth, soil fertility, and rainfall on wheat and barley yields in Mediterranean climate regimes, and calibrated to typical yields of ancient wheat and barley varieties [39][40][41][42][43][44][45][46][47][48].…”