Drought tolerance during germination of native and commercial forage grasses: implications for pasture management in semi-arid lands

RODRIGUEZ, DANA AYLEN; SCARFÓ, MARIA CECILIA; MILANO, CLARA; TORRES, YANINA ALEJANDRA; LOYDI, ALEJANDRO

ARID LAND RESEARCH AND MANAGEMENT

TAYLOR & FRANCIS INC

Año: 2026 p. 1 - 16

1532-4982

Drought stress limits forage production in semi-arid grasslands, threatening the sustainability of grazing systems. This study evaluated whether native perennial grasses from the semi-arid Pampas of Argentina exhibit drought-tolerant germination traits comparable to commercial forages. Germination experiments were conducted using diaspores of eight native and two commercial grass species (cool- and warm-season functional groups) exposed to six water potential levels (0 to −1.5 MPa). Germination responses were analyzed using the hydrotime model to estimate the hydrotime constant (θH) and the base water potential for 50% germination (Ψb(50)). Warm-season species showed more negative Ψb(50) values (−0.96 to −1.21 MPa) and lower θH (1.90–2.69 MPa.day), indicating greater tolerance to water stress than cool-season species, which exhibited broader variation (Ψb(50): −0.55 to −1.27 MPa; θH: 3.48–9.24 MPa.day). Within the cool-season group, the commercial Thinopyrum ponticum showed the highest tolerance, being the only species able to germinate at −1.5 MPa. Among native species, Jarava plumosa, Pappophorum vaginatum, and Digitaria californica displayed drought-tolerant germination traits comparable to or exceeding those of commercial species. These results demonstrate that native grasses possess diverse and effective germination strategies under water limitation, supporting their integration into forage systems and restoration efforts aimed at increasing resilience in semi-arid rangelands.