Fruitfulness of grape vine buds

Abstract

One of the most important biological characteristics of the grapevine (Vitis vinifera L.) is its capacity to form buds in the axil of each leaf all along the length of its shoots. Grape buds are generally classified as mixed buds, i.e., both leaves and flowers develop from the same bud. Four types of buds are recognized in the grapevine which, for sake of brevity, may be referred to as (a) primary, (b) secondary or accessory or replacement, (c) basal, and (d) latent. As a general rule, on a young shoot two growing points are formed in the axil of each leaf, but as they are enclosed in a common protective scale, they appear as one bud. One of these develops in the same season in which it is formed and gives rise to a lateral. The lateral may soon be checked in growth and drop off in winter or may continue to grow and mature into a cane at the end of the season. However, where no lateral is produced, as it often happens at the proximal bud positions, two primary buds may be formed at the node. The other growing point, in the meantime, develops two accessory or secondary buds, one on each side, and the three thus formed remain enclosed in common scales so that they appear as one large bud which is often referred to as "eye."9 The accessory buds, also called replacement buds, seldom develop further, and the central bud constitutes the main unit. As all these buds arise in the axil of the leaf, they are called axillary buds. The compound bud (eye) remains dormant over winter in temperate climate and resumes growth in the following spring. If the central bud is killed by