Bud Necrosis Characteristics of 'Hongisul' Grape

Abstract

The germination of the buds in 'Hongisul' grapes is poor and especially the high ratio of shoots where the flowers failed to emerge it was difficult to secure a sufficient amount of harvest. Thus, in this study, the necrosis and the periodical change in the buds were observed morphologically and also the cause of necrosis of the bud was investigated in order to understand what was causing the low germination and flowering. There was no change in the size of the bud after June and based upon external observation, there wasn't any retrogression or withering. However, based on a microscopic examination, the ratio of whole bud and main bud necrosis of the 'Hongisul' grapes continued to increase after August, and specially the ratio of the main bud necrosis continued to increase up to October. As for the size of the buds on the shoots, the buds located on the 1(st)-3(rd) nodes from the basal part were small whereas the buds located on the 4-10(th) nodes were comparatively larger in its size. The ratio of necrosis of the bud was the highest at the 1(st) and 2(nd) bud, meaning that the buds located at the basal part of the shoot were defective compared to those located at the end of the shoot. It was also found that when the growth of the shoot is active and the shoot diameter is thick, it hindered the development of the buds. Therefore, it was judged that long pruning of 'Hongisul' grapes would help the emergence of the flowers as you could use the buds that have comparatively developed better.