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Highlights: [•] We assessed yield and persistence of elite grass cultivars across Mediterranean sites. [•] Cultivar adaptive responses were modelled as a function of relevant climatic variables. [•] Our results support crop recommendation and breeding, also in view of climate change. [•] Tall fescue has general interest for Mediterranean drought-prone areas. [•] Completely summer-dormant cocksfoot with improved yield can be useful in warmer sites. [ABSTRACT FROM AUTHOR]

Abstract: Stress-tolerant forage resources are increasingly needed for the environmental and economic sustainability of extensive Mediterranean livestock systems. Perennial forages such as cocksfoot (Dactylis glomerata L.) can be a valuable alternative to annuals, if they can survive across successive summer droughts. One Mediterranean cultivar of cocksfoot subsp. hispanica with complete summer dormancy (Kasbah), five non-dormant (Delta 1, Jana, Medly, Ottava) or incompletely dormant (Currie) Mediterranean cultivars of subsp. glomerata, and one Continental cultivar (Porto) of subsp. glomerata, were evaluated for dry matter yield over three years and persistence as final plant survival in six sites of Algeria, France, Italy, Morocco and Portugal, with the objectives of: (i) modeling adaptive responses and targeting cultivars as a function of environmental factors associated with genotype×location (GL) interaction; (ii) defining plant ideotypes, adaptation strategies and opportunities of international co-operation for regional breeding programmes. Adaptive responses were modeled by joint regression, additive main effects and multiplicative interaction (AMMI), and factorial regression. The most predictive models were: (i) factorial regression as a function of site spring–summer drought stress (as long-term potential evapotranspiration minus actual water available), for yield; (ii) AMMI including one GL interaction principal component related to site annual and spring–summer drought stress, for persistence. GL interaction of crossover type for yield and persistence was large and mainly associated with the summer dormancy trait. Completely dormant germplasm was specifically adapted to severe drought. Non-dormant Mediterranean cultivars tended to be specifically adapted to moderate drought stress, although they varied to some extent in adaptive response to drought-stress levels. The Continental cultivar was generally misadapted. The completely summer-dormant germplasm also tended to have greater general persistence across locations. Early flowering tended to correlate with higher yield and persistence of the cultivars across locations. Considerations on experimental conditions along with previous physiological studies from three sites suggested that water use efficiency of the cultivars tended to parallel their site-specific yield response. On the whole, the results suggest different adaptation targets, plant types, genetic resources and cultivar recommendation for northern Africa and southern Europe. Summer-dormant material of subsp. hispanica has prevalent interest for northern Africa. Breeding widely adapted, non-dormant or incompletely dormant Mediterranean cultivars of subsp. glomerata has prevalent interest for southern Europe, especially when targeted to moderate crop duration (3–4 years). However, completely summer-dormant germplasm could gain adaptive potential for Mediterranean-climate European regions in the future, to mitigate the effects of the predicted increasing drought due to climate change. [Copyright &y& Elsevier]

Extensive livestock is a basic socio-economic feature of the Mediterranean region whose environmental and economic sustainability depends on the ability of forage resources to withstand climatically stressful conditions. Perennial forages such as tall fescue can be a valuable alternative to annuals, if they can survive across successive summer droughts. Three-year dry matter yield and plant survival of five cultivars of Mediterranean-type tall fescue were evaluated in six sites of Algeria, France, Italy, Morocco and Portugal, with the following objectives: (i) modelling adaptive responses and targeting cultivars as a function of environmental factors associated with genotype × location interaction; and (ii) defining plant ideotypes, adaptation strategies and opportunities for international co-operation for regional breeding programmes. Site mean yield and winter temperatures were positively correlated, whereas sward persistence was positively correlated to lower site heat and drought stress. Cultivar adaptation was adequately modelled by factorial regression as a function of site spring-summer (April-September) drought stress (long-term potential evapotranspiration minus actual water available) for yield, and annual drought stress for final persistence. Specific-adaptation responses to high- or low-stress environments emerged which were consistent with drought-stress levels of cultivar selection environments. However, the wide-adaptation response of cultivar Flecha suggested that breeding for wide adaptation can be feasible. [ABSTRACT FROM AUTHOR]