Effects of hot water treatments on growth of Botryosphaeriaceae fungi and bud vitality of grape scion and rootstoks in controlled conditions.

ensitivity of four Botryosphaeriaceae fungi species (Botryosphaeria dothidea, Diplodia seriata, Lasiodiplodia theobromae and Neofusicoccum parvum), five grapevine rootstocks (1103P, 110R, 41B, Kober 5BB and Ramsey) and ten grapevine cultivars (Alphonse Lavallée, Cabernet Sauvignon, Cardinal, Cal Karasi, Hamburg Muscat, Italia, Pembe Gemre, Sultana Seedless, Trakya Ilkeren and Yalova Incisi) to hot-water treatments (HWTs) were tested in vitro and under controlled conditions. Centrifuge tubes (containing fresh mycelial agar plugs) were held on heating block for 30, 45 and 60 minutes at 47, 48, 49, 50, 51, 52 °C. Fungal discs were then transferred to potato dextrose agar to allow mycelial growth at 24°C for 5 days. In a second experiment, 30-cm-grapevine canes were HWT treated at 51, 52 and 53°C for two periods: 30 or 45 minutes, then plunged into a cool bath at 15°C for 10 minutes. Rootstocks and cultivars were planted immediately after the treatment in rooting benches for 15 days to evaluate bud vigour under greenhouse conditions (at 24°C and 85% RH for 16/8h day/night). The most sensitive fungal species to HWT in vitro was D. seriata, while the most resistant was L. theobromae. The lethal temperature and time combinations for D. seriata and L. theobromae were 47°C-30 min and 51°C45 min respectively. Italia and Kober 5BB were the most tolerant varieties to HWT and treatments of 53°C-45 min reduced the vigour rates to 37.3% and 46.7% for Italia and Kober 5BB, respectively. B S Davut Soner AKGÜL1 Yüksel SAVAŞ2 Nurdan GÜNGÖR SAVAŞ2 Adem YAĞCI3 1 Çukurova Üniversitesi, Ziraat Fakültesi, Bitki Koruma Bölümü, 01250, Adana/Türkiye 2 TC GTHB, Manisa Bağcılık Araştırma Enstitüsü 45125, Manisa / Türkiye 2 Gazi Osman Paşa Üniversitesi, Ziraat Fakültesi, Bahçe Bitkileri Bölümü, 60250, Tokat / Türkiye Sorumlu Yazar: sakgul@cu.edu.tr