Freezing tolerance of some grape cultivars and rootstocks
Low temperatures can cause significant yield losses in vineyards due to winter bud injury. In order to cope with this problem, it is important to choose frosts-resistant cultivars and rootstocks in grape growing zones, and to identify resistant grape genotypes in the excessive frost-risk zones especially at high altitudes. In this study, 4 grape cultivars Ekşi Kara, Gök Üzüm, Müsküle and Antep Karası, and 2 grape rootstocks 99R and 110R were tested for resistance to low temperatures by single node cuttings. The test materials were taken at the end of vegetation period from producer vineyards at the 1400 m altitude and subject to low temperatures as -12 and -18°C for 12 and 24 h in the thermo-cabin Ahm ESDE IN 450 brand was used. The injury rates of primary, secondary and tertiary primordia of the winter buds were examined under a binocular microscope (×10) and the sprouting ratios of the tested material were determined in the growth cabinet in the laboratory. The highest damage rate of all primordia exposed to -18°C for 24 h was observed with 100% damage in Antep Karası. At the same conditions while the lowest damage was observed primary, secondary and tertiary primordia in Gök Üzüm with 96.67, 90 and 86.67%, respectively. The cold damage rate in 110R rootstock was 83.33% in primary buds and 61.33% in secondary and tertiary buds, and in 99R rootstock was 80, 60 and 56.67%, respectively. Undamaged buds of cuttings were sprouted and developed well in growth camber. The results showed that rootstocks were more resistant to freezing temperatures than the grape cultivars. The present study reveals the indigenous grape Gök Üzüm was found more frost resistant than the introduced cultivars. In addition, black colored Ekşi Kara was more resistant to frost than white Gök Üzüm. These two cultivars are also natively grown in Anatolia.
Doğan, O., Kara, Z., Yazar, K. and Sabir, A. (2020). Freezing tolerance of some grape cultivars and rootstocks. Acta Hortic. 1276, 223-230
native grape cultivars, frost damage, low temperatures, frost tolerance