Freezing Tolerance of Opuntia spp.
Keywords:Freezing injury; cold hardiness; Cacti; Opuntia varieties; Nochtli (cactus pears in the Nahuatl language), tuna or prickly-pear fruit
Frost is a serious abiotic stress affecting crops in the Chihuahuan desert. An unusually severe frost occurred 11-14 December 1997, and caused serious injuries in Opuntia spp. commercial orchards for nochtli, tuna, or prickly-pear fruit production in Mexico’s State of Zacatecas and at the Centro Regional Universitario of the Universidad Autónoma Chapingo germplasm collection. An evaluation of resistance to that frost was carried out in a collection of 73 varieties (five plants each) of Opuntia spp. in the germplasm bank. The percentage of dead cladodes (%DC) was measured in individual plants that were used as the experimental unit. Means and standard deviations (?, ±?) of the %DC are discussed. The varieties “Duraznillo” and “Tapón Aguanoso” were not affected by the freeze. The “Amarilla CE”, “Amarilla SM”, “Morada SM”, “Camuezo” and “Zarquita” varieties were only slightly affected (0%DC to 10%DC) by the freeze, so these varieties, in combination with the “Tapón Aguanoso” and “Duraznillo” varieties, are the only varieties able to withstand cold temperatures without serious injury. In particular, the COPENA varieties were quite susceptible to freezing weather. These findings will be useful for Opuntia on crop research and genetic improvement programs.