Seyed Mehdi Mirbaqeri; Rouhollah Karimi; Mousa Rasouli
Abstract
In order to investigate the effect of foliar application of potassium sulfate (K2SO4; 0, 1.5 and 3 percent) and iron chelate (Fe-EDDHA; 0, 0.5 and 1 percent) on fruit set, fruit yield and quality, leaf mineral nutrient content, raisin yield and autumn and winter cold tolerance of ‘Bidaneh-Sefid’ ...
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In order to investigate the effect of foliar application of potassium sulfate (K2SO4; 0, 1.5 and 3 percent) and iron chelate (Fe-EDDHA; 0, 0.5 and 1 percent) on fruit set, fruit yield and quality, leaf mineral nutrient content, raisin yield and autumn and winter cold tolerance of ‘Bidaneh-Sefid’ grapevine, a factorial experiment was done based on randomized complete blocks design in a commercial vineyard in Bahareh village of Malayer city during 2016-17. The highest fruit set percentage and yield was achieved in 1.5 percent of K2SO4 in combination with 0.5 percent iron chelate. Berries K, Fe and Mn concentration had a positive and significant correlation with fruit yield per vine. Raisin yield was found to be highest in combined treatments of 1.5 percent K2SO4 and 1 percent Fe-EDDHA and the lowest raisin yield was related to control vines. The highest autumn cold hardiness was recorded in K2SO4 (3%) × Fe-EDDHA (1%) treated vines. However, the highest winter cold tolerance was achieved in K2SO4 (3%) × Fe-EDDHA (0.5%) treated vines. The lowest cold tolerance was observed in control vines. There was a positive and significant correlation between cold tolerance and K content and negative correlation with Mg concentration. Totally, the highest fruit and raisin yields and their desirable qualities were obtained with K2SO4 and Fe-EDDHA at moderate concentration. However, the highest buds cold tolerance was obtained with the combination of these fertilizers at higher doses.
Rouhollah Karimi; Ahmad Ershadi; Mahmoud Esna-Ashari; Masoud Mashhadi Akbar Boojar
Abstract
Screening of native cultivars and understanding of the mechanisms involved in cold hardiness in grapevines is needed to match cultivars appropriately with growing sites and aid in breeding and selecting cultivars with improved freezing tolerance. In this study cold hardiness of fifteen grapevine (Vitis ...
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Screening of native cultivars and understanding of the mechanisms involved in cold hardiness in grapevines is needed to match cultivars appropriately with growing sites and aid in breeding and selecting cultivars with improved freezing tolerance. In this study cold hardiness of fifteen grapevine (Vitis vinifera L.) cultivars were evaluated using tetrazolium stain test and post freezing budbreak assays during six months from acclimation till deacclimation stages. Moreover, seasonal changes pattern in soluble proteins, total phenol and Malondialdehyde (MDA) of buds were measured during this period. Significant differences (P≤0.01) were found among cold hardiness of cultivars in all stages. ‘Bidaneh Ghermez’ and ‘Khalili’ (LT50= -22 and -22.6 ºC in respectively) were the hardiest ‘Ruby’ and ‘Perlette’ (LT50= -16.1 and –16.9 ºC in respectively) were the least hardy cultivars in January. Soluble proteins and total phenol concentrations of buds increased during cold acclimation from November to January then decreased in March. The concentration of these compounds was higher in cold hardy such as ‘Bidaneh Ghermez’ and ‘Khalili’ cultivars than least hardy ones, indicating the positive relationship of these compounds with freezing tolerance. The measured MDA in onset and end of dormancy period was lower than its concentration in deep dormancy in January. Lower MDA concentration was found with cold hardy cultivars ‘Khalili’ and ‘Bidane Ghermez’ in comparison with cold sensitive cultivars, ‘Perlette’ and ‘Yaquti’. Our results indicated that high accumulation of soluble proteins and total phenol in cold hardy cultivars resulted in improved membrane stability and freezing tolerance.