EFFECT OF DIFFERENT FACTORS AFFECTING POLYPHENOLIC EXUDATION AND IN VITRO CULTURE ESTABLISHMENT IN SOME GRAPE (VITIS VINIFERA L.) GENOTYPES

摘要

In grapes, polyphenol exudations is the major hindrance in in vitro culture establishment as it leads to excessive media browning and explant necrosis. Hence to minimize it, an experiment was conducted to estimate the in vivo phenol contents in sevengrape genotypes at monthly interval and its effect on in vitro culture establishment from field-grown plants. Wide variability was noticed with regard to in vivo phenol content in the two different explants, i.e. shoot tip and nodal segment. Nodal segment was found superior over shoot tip and the best time for culture establishment was mid-April. Of the three pre-treatments employed for minimi ing the in vitro phenol exudation, the most effective was the collection of nodal segments during mid-April followed by agitation in antioxidant solution (50 mg/1 L-ascorbic acid + 75 mg/1 citric acid). This treatment also gave the highest establishment success in Pusa Navrang (51.7%), while Hybrid 76-1 (28.9%) registered the minimum success. The mean values forin vitro phenol exudation was minimum in Centennial Seedless (0.056 mg/ml medium) while it was highest for Pusa Navrang (0.141 mg/ml medium). The established cultures were then subjected to micropropagation.