Sustainable stewardship of the landrace diversity

Abstract

Landraces are heterogeneous populations and their variability goes through continuous alterations because of physical, genetic, and epigenetic procedures exacerbated by the ongoing climatic changes. Appropriate stewardship of landrace diversity is pivotal to promote its longevity in a manner that is sustainable from the farming perspective. A seed multiplication procedure is presented based on the assumption that in order to improve effectiveness in resource use and increase seed productivity, landraces should comprise genotypes which minimize intra-species competition. These aforementioned genotypes should be of the "weak competitor" ideotype, which are selected so as to alleviate the interplant competition and reach as high as possible crop stand uniformity. Stand uniformity is essential to ensure the same growing conditions for each plant. Reduced intra-crop inequality and equal use of inputs by individual plants will optimize crop performance. Precisely, the "weak competitor" is most often of high yield potential due to a negative association between yielding and competitive ability. Therefore, the suggested procedure involves initial reproduction at nil-competition (widely spaced plants to preclude any plant-to-plant interference for inputs) where "off-type" and low yielding plants are omitted, followed by subsequent multiplication at dense stands. This may represent an effective cultural practice to improve also the landrace health status concerning seed-borne diseases in the absence of certification systems.