Format: ORAL

Giacomo Boscarol1, Elisa Petrussa1, Giacomo Trotta1,2, Francesco Boscutti1, Dora Scarpin1, Enrico Braidot1, Valentino Volpe3, Stefano Barbieri3, Michele Fabro3, Marco Vuerich1

1 University of Udine, Udine, Italy 2 University of Trieste, Trieste, Italy 3 Servizio fitosanitario e chimico, ricerca, sperimentazione e assistenza tecnica, ERSA, Pozzuolo del Friuli, Italy

One of the effects of global change is the alteration of hydrological events, which affects many human activities, including agricultural ones. Understanding how maize (Zea mays L.), one of the most important staple crops worldwide, responds to these modifications is important to adapt to climate change. Drought stress during maize germination, flowering and pollination can lead to decreased plant growth, nutrient uptake, and grain yields. Prolonged periods of drought can also significantly increase the spread of diseases, which reduces yield quality. In this context we monitored 40 maize fields composed by both irrigated and non-irrigated areas, along a pedoclimatic gradient in NE Italy, throughout the 2022 and 2023 seasons, at four phenological stages (i.e., beginning of stem elongation, flowering, milk maturation, dent maturation). In particular, we considered the plant individual functional response (i.e., plant height, SLA, leaf DMC, leaf chlorophyll, carotenoid and flavonoid content, kernel DW, kernel C:N, kernel 13C), and the kernel mycotoxins content (aflatoxins and fumonisins), in relation to irrigation conditions and climate data (i.e., total precipitation, mean temperature). We found that the soil structure effect was overruled by the effect of climate and/or irrigation. As we expected, the absence of irrigation and low total precipitation led to a reduction of plant biomass and kernel production, whereas interaction between irrigation and phenological stage had significant effects on leaf pigments (i.e., chlorophyll) and secondary metabolites (i.e., flavonoid). Moreover, irrigation enhanced the kernel C:N ratio and 13C, whereas reduced the amount of aflatoxins. Our further investigations aim at evaluating the interplay between the climatic variables, the soil structure, and the individual traits on the ultimate content of mycotoxins in the kernel, with two distinct irrigation regimes and at the given different phenological stages, adopting a structural equation modelling approach.