Field evaluation of frost tolerance in 10 olive cultivars

Abstract

Frost damage was evaluated in 1-year-old olive trees in the cultivars ‘Arbequina’, ‘Cornicabra’, ‘Empeltre’, ‘Frantoio’, ‘Hojiblanca’, ‘Manzanilla Cacereña’, ‘Nevadillo de Jaén’, ‘Picual’, ‘Picudo’ and ‘Verdial de Badajoz’ in Madrid, Spain. Temperatures fell to −6.5 and −10.5°C on 11 November and 16 December 2001, respectively. In May frost damage was visually assessed. The olive trees were pruned to the ground and dry matter was quantified in shoots and leaves with and without signs of frost damage. In August resprouting was visually evaluated. Visual assessment overestimated frost damage compared to the quantitative evaluation. Leaves had a lower resistance to frost than shoots. Shoot frost resistance was linearly correlated to the cultivar's resprouting capacity. Significant differences in frost resistance were found between cultivars. ‘Cornicabra’ and ‘Arbequina’ had a low percentage of frost-damaged shoots and a high resprouting capacity after frost. The cultivars which were the least resistant to frost were ‘Empeltre’, ‘Frantoio’ and ‘Hojiblanca’. These cultivars had a high percentage of frost-damaged shoots and almost no resprouting capacity. ‘Picual’, ‘Picudo’, ‘Verdial de Badajoz’, ‘Manzanilla Cacereña’ and ‘Nevadillo de Jaén’ had an intermediate frost resistance.