Determination of Bud Fruitfulness of Newly Bred Foxy Grape (Vitis labrusca L.) Cultivars Under Vineyard and Growing Room Conditions

It is necessary to carry out bud fruitfulness studies of new cultivars and determine the correct pruning and appropriate crop load. Since bud fruitfulness may vary depending on the grape cultivar, bud fruitfulness of the new grape cultivars should be determined by research. In the present study, the objective was to determine bud fruitfulness (number of clusters per bud) of four Turkish ('Rizessi', 'Rizellim', 'Ulkemiz' and 'Celiksu') and one American ('Concord') foxy grape cultivars grown in Samsun ecological conditions in Turkey. To this end, the first 10 buds from the base to the top of 1-year-old canes were sprouted under the vineyard, and single-bud-cuttings were taken from the same canes sprouted under growing room conditions. Budburst (%) and cluster percentage (%), the number of clusters per bud were calculated in both conditions. It was determined that the maximum bud fruitfulness differed between the 4th and 10th bud ranks. All cultivars had different bud fruitfulness according to the bud ranks. The bud fruitfulness of the first and second buds for ' Celiksu', 'Rizellim', 'Ulkemiz', and 'Concord' were less than one cluster per bud when sprouted under vineyard conditions. The number of clusters counted in the winter buds was the highest in the 6th node (3.5) of the 'Rizessi' cultivar, followed by the 7th node (3.4) of the same cultivar and the 10th node (3.4) of the 'Rizellim' cultivar. All these cultivars had more than one cluster per bud at the growing room conditions at the first bud level. The most fertile buds were the 6th and 7th in 'Rizessi', 6th-10th in 'Celiksu', 8th-10th in 'Rizellim', and 5th-7th buds in 'Ulkemiz'. 'Rizessi' and 'Ulkemiz' should be pruned medium long (seven buds per cane), while 'Celiksu' and 'Rizellim' should be pruned so that canes have at least 10 buds. 'Concord' grape was suitable with between four and five buds and spur pruned.