Anatomical Study of Primary Bud Necrosis in Vitis vinifera

Primary bud necrosis in grapevine is a physiological disorder observedin the compound buds. this study was conducted to investigate the anatomicalchanges in cv. askari grapevine in winter dormant buds. bud samples weretaken from askari grapevine at sisakht vineyards, south-western of iran.compound buds were dissected and assessed under a binocular microscope at10-40x magnification and a digital microscope (dinolite-am413t) was usedfor taking photos. the results showed that the bud necrosis incidence wasobserved in primary buds more than in the secondary buds. anatomical observationsshowed that pbn disorder occurred in central buds as brown smallspot and gradually developed in the whole bud and bud necrotic remained oncanes and did not abscission. on the results of present study, dissecting budsin autumn can raise awareness of pbn and fruitfulness of bud in the followingspring, hence, growers should determine the level of bud necrosis prior towinter pruning so that pruning techniques might be adjusted to account for thebud damage.