initiation, botanical term for the start of the vine’s fruiting when the first signs of bunches are evident as small pieces of tissue in the developing bud. These buds are themselves developing beside the leaf stalk on the shoots as they grow in spring. Initiation starts simultaneously with the flowering stage of the growing season. Warm, sunny weather conditions at this time favour initiation, with one, two, occasionally three, or very rarely four bunches per shoot initiated. When this shoot bursts the following year, it will be termed fruitful. Cold, cloudy weather depresses fruit bud initiation.