Addressing the Role of Landraces in the Sustainability of Mediterranean Agroecosystems

Abstract

Wheat yields are predicted to decrease over the next decades due to climate change (CC). Mediterranean regions are characterized by low soil fertility and stressful conditions that limit the effect of technological improvements on increasing yield gains, while worsening the negative CC impacts. Additionally, organic farming (OF) lacks specifically adapted genetic material. Accordingly, there is a need to search for varieties adapted to these conditions and whose cultivation may help semi-arid agroecosystems sustainability, focusing on specific agronomic and functional traits. To this purpose, wheat landraces and modern wheat varieties were evaluated under Mediterranean rainfed conditions during three growing seasons under contrasting situations: A conventional farm and an organic farm. Results regarding straw production, weed biomass and biodiversity, and grain N concentration suggest that the cultivation of landraces under Mediterranean rainfed conditions can enhance agroecosystem sustainability through positive effects on ecosystem services such as soil quality, functional biodiversity, or grain protein content, without significant reductions in grain yield. Results highlight the relevant role of wheat landraces as genetic resources for the development of cultivars adapted to Mediterranean agroecosystems conditions, especially for organic farming, but also for conventional agriculture.

GGE Biplot Analysis to Explore the Adaption Potential of Italian Common Wheat Genotypes

“…Within the European context, the large genetic yield gap [4] and the decline in climate resilience of European wheat [5] amidst future projected climate changes [6] are testimony to the challenges facing wheat cultivation. More specifically, the Mediterranean climate is characterized by low and erratic distribution of rainfall, along with increasing temperature towards the end of the crop cycle, conditions that compromise yield stability [7,8]. Not surprisingly, climate-change induced wheat yields are projected to decrease by up to 49% by 2050 in Southern Europe [6], evidencing the insufficient preparation of wheat breeding programs and cultivar selection for climatic uncertainty and variability [5].…”

“…To this end, there has been a growing interest in on-farm conservation of wheat landraces, which are domesticated, traditional, regional ecotypes, locally adapted to their respective natural and cultural agricultural environments. Emerging research on soft wheat has emphasized the role of landraces and old varieties (released before 1950, or the phase commonly referred to as the "Green Revolution"), individually or in mixed populations, as genetic resources to improve sustainability in Mediterranean rainfed agroecosystems [7,[12][13][14][15][16]. In Italy, soft wheat comprising 40% of the total wheat cultivated, showed a negative trend in gross production in 2021 that was −5.43% compared to the previous five-year average [17].…”

“…Noteworthy, although yield selection remains a preeminent selection criterion, an evaluation of crop resilience is an important auxiliary to yield [5], as are functional and technological properties [7,[14][15][16]. This is reflected in the Organic Regulation EU 848/2018 prescribing cultivars, suitable for organic agriculture, with the following attributes: enhanced genetic diversity, disease resistance or tolerance, adaptive potential to diverse local soil and climate conditions, and the ability to produce high-quality food [18].…”

Exploring the End-Use Quality Potential of a Collection of Spanish Bread Wheat Landraces

“…Field characterization can aid breeders when selecting local donor materials that ensure good end-use properties in the derived elite cultivars without high detriment to agronomic performance. In addition, although landraces perform worse than modern varieties in terms of yield, their yield stability can be higher since they are more resilient to adverse conditions and can have a better performance in unfavorable conditions [86][87][88]. It has been proposed that landraces could provide genetic diversity that may contribute to improved yields in rainfed agroecosystems, where heavier kernels may compensate for lower spike fertility [89,90].…”

Modern Wheat Varieties as a Driver of the Degradation of Spanish Rainfed Mediterranean Agroecosystems throughout the 20th Century

“…Weed root biomass has not been considered in this study because it lacks minimally reliable data on which to base it. In the absence of trials in which this variable has been measured, regardless of the agroclimatic conditions, it must be added that the weeds complex present in plots cultivated with OV under organic management is different from that of MV under industrialized management [36] and, therefore, it is not possible to attribute the same R:S ratio for weeds in this study.…”