Differentiated Weed-Suppressive Ability of Modern and Old Durum Wheat Cultivars after Long-Term Cultivation under Semi-Arid Climate

Abstract

Durum wheat (Triticum turgidum spp. durum) is one of the most important grain crops cultivated across the Mediterranean Basin, where a strong return to local landraces cultivation is occurring to meet the market demand for high-quality food and low-input cropping systems. A characterisation of the long-term effect (10 years) of durum wheat landraces and modern cultivars on the potential and real weed flora is still lacking. Hence, a multilocation trial over 10 farms in Central-Eastern Sicily was carried out to investigate the repeated cultivation of several old landraces (OLD) and modern cultivars (MOD) on the abundance and diversity of weed flora. Overall, OLD was associated with a 47% reduction of the soil seedbank size and to −64% of the aboveground weed biomass compared to MOD. In addition, diversity indices pointed out a high similarity between MOD and OLD farm groups for the soil seedbank, while a lower diversity was found in OLD for aboveground weed communities. From the principal component analysis emerged that the species compositions of MOD and OLD were quite separated for both soil seedbank and real flora, with the latter showing few specific associations with major weeds. These findings demonstrated the indirect effect of durum wheat landraces in sustainably reducing weed pressure without the adoption of chemical weed control.

Responses of soil seedbank and aboveground weed communities to globe artichoke–cropping systems: an on-farm analysis

“…Nevertheless, the very low biomass levels of aboveground weeds for ART might be attributed on the progressive decrease of the soil seedbank size on the one hand, and on its combined allelopathic plus competitive ability on the other hand. Similar findings were also reported by Alsaadawi et al (2012) concerning the repeated cultivation of sunflower on weed number and biomass, with a higher weed-suppressive ability shown by allelopathic sunflower cultivars, and by Scavo et al (2022) concerning durum wheat landraces. Concerning the differences between soil seedbank and aboveground weeds, especially about past-ART and ART-WHEAT, it is known that emerged weeds reflect a recent influence of farming practices, whereas seedbank communities are more representative of long-term effects associated with farming practices (Buhler et al 1997; Dekker 1999).…”

“…Concerning the biological groups, 73% of the identified taxa were therophytes and 23% hemicryptophytes, while the only geophyte was Bermuda buttercup ( Oxalis pes-caprae L.). Therefore, the total seedbank was primarily composed of annual therophytes, similar to results from Scavo et al (2022). Seven major species or genera (with an RD ≥ 6%) dominated the seedbank (Table 2): in decreasing order, scarlet pimpernel ( Anagallis arvensis L.), P. oleracea , Silene sp., Fumaria sp., Chenopodium sp., A. retroflexus , and black bindweed [ Polygonum convolvulus L. var.…”

“…In particular, the interactions between cropping system treatments (ART, past-ART, ART-WHEAT, control) and weed communities were tested through principal component analysis (PCA) on the correlation matrix of density data, one for the soil seedbank and one for aboveground weeds. Before PCA, the seven major weeds (RD ≥ 6%) for the soil seedbank and the six major weeds for aboveground weeds were standardized by log ( x + 1) transformation (Scavo et al 2022). In accordance with Legendre and Legendre (2012), PCA results were displayed on “distance” biplots derived from the first two principal components (PCs) explaining the maximum variance.…”

“…Then, three sampling zones within these areas were selected by excluding the nonhomogeneous areas and the outer 3-m borders. The weed flora has been analyzed in terms of soil seedbank (potential flora) and aboveground communities (actual flora), considering both the abundance and diversity (Scavo et al 2022). The collection of soil cores was performed from July 13 to 31, 2021, while aboveground weed samples were taken from November 4 to 10, 2021.…”

Wheat Response and Weed-Suppressive Ability in the Field Application of a Nanoencapsulated Disulfide (DiS-NH2) Bioherbicide Mimic

“…In wheat organic farming, weeds are recognized by farmers as the greatest yieldlimiting constraint, followed by drought, nitrogen supply, and pedo-climatic conditions [3,4]. Indeed, weeds highly compete with wheat plants for water, nutrients, and light, and, in some cases, the competition acts in synergism with the release of allelochemicals into the environment [5].…”