TOTAL PHENOLICS AND ANTHOCYANIN CONTENT OF TWO RED GRAPE (VITIS VINIFERA L.) CVS SAHEBI AND HALAGHO CULTIVARS AS AFFECTED BY PRUNING SEVERITY AND CANE LENGTH

A popular and important grape 'Sahebr and a less known local grape 'Halagho' in Iran, were studied to unmask the influence of pruning severity and cane length on fruit bioactive potentials; total phenolic and anthocyanin content in which they affected significantly. In this investigation, effects of 4, 6 and 8 buds per cane with pruning intensity as light, moderate and severely pruned and their interaction in the course two consecutive years, 2017 and 2018 in 'Sahebr and 'Halagho' were studied. Results revealed striking differences which in either cultivar, pulp phenolic content was 2 to 5 fold higher in 2017 compared to 2018 with the severely pruned 'Halagho' at the highest (5.14 mg/g DVV). Whereas, lightly pruned 'Halagho' with 6 buds per canes had the highest peel anthocyanin content (1.09 mg/g DVV), in the same condition but with severely pruning 'Halagho' showed the highest anthocyanin content in pulp (0.86 mg/g DVV) while in the second year, 2018, severely or lightly pruned this type with 6 buds per cane had a significant increase in phenolic compound accumulation (10 mg/g DVV). From the results of this experiment, it could be concluded that the pruning of the vines is a stressor and generates enhanced phytochemical constitutes to possibly mitigate the negative consequences. However, variation in the biochemical properties manifested a notable grape cultivar dependency in addition to the time factor, which was more pronounced in 'Halagho' than Zahebr. To some extent the effect of cultivars on the differences of two cultivars was predominant.