Tropical and subtropical fruits (2+1)

Bud Analysis

	Characteristics	Muscadinia	Euvitis
1	Chromosome No(2n)	40	38
2	Nature of tendril	Unforked	Forked
3	Bark	Tight	Loose
4	Presence of lenticels	Present	Absent
5	Seed shape	Break absent	Breaked
6	Presence of diaphragm at the node of shoot	Absent	Present


Sampling is an important pre-requisite. A minimum of 20 buds is necessary for each bud position for estimating the cropping potential with a reasonably high degree of precision. In varieties like Muscat prediction of fruitfulness is not necessary because most of the buds are fruit full in these varieties. The number of bud position for which buds have to be collected should therefore be fixed according to the variety. In general, it is better to collect buds at least for the first ten bud positions. Thus a total of 200 buds have to be collected. The collection may be done at least from five randomly selected vines in each variety. In each vine, at least ten canes should be done roughly about 100 days after pruning i.e. a month or two prior to next pruning. Immature, green, disease infected and unhealthy canes have to be rejected. The buds in the axils are scooped out with a piece of wood of the stem and placed in glass vials containing FAA (Formalin Acetic Acid, Alcohol= 5:5:50).

The grape bud is a compound bud with two or three secondary buds, covered by a lignified protective scale. Under a sterio microscope, the protective scale and secondary buds are removed one by one. The scale & thick packed inter-woven tormentor’s hairs are next removed carefully with a needle. The shoot primordial (differentiated bud unexpanded) can be seen in the centre of the bud. The bud that shows the inflorescence primordial as a closely packed miniature branch besides the leaf primodia is recorded as a “reproductive bud while the one locking this inflorescence (cluster) primordium is noted as vegetative unproductive bud. The number of productive buds at each bud position is thus recorded from the first upwards on the cane. The bud fertility is expressed as a percentage on the number of buds examined and the percentage noted down for every bud position will reveal the most productive position of the cane. Pruning can be in the next season above the bud which records the highest percentage of fertility to obtain good crop.