Frost hardiness and production of Opuntia forage clones in the Mendoza plain, Argentina

Frost resistance of Opuntia forage clones was evaluated for different plant ages after freezes of −16 and −17°C. Above-ground biomass production of 3-year-old clones established in a dune was also estimated. Frost damage was visually estimated, integrating the individual cladode damage over the entire plant. Biomass was based on a total above-ground harvest of typical plants of each species. Young cladodes from 9-month-old plants had damage higher than 85%. The 3-year-old plants exhibited mean frost damage that ranged from 0.3% in O. paraguayensis K. Sch. to 34% in O. ficus-indica L. f. inermis (Web.) Le Houér. (San Juan accession). O. spinulifera Salm-Dyck f. nacunianaLe Houér. f. nov. appears to be the most promising species for extremely cold winter areas. The 3-year-old plants of this species had 5% mean frost damage, a dry biomass production of 2 kg plant−1and 6.5% crude protein content in young cladodes.