Influence of gamma radiation on morpho-physiological and biochemical traitsof in vitro raised wine grape (Vitis vinifera L.) genotypes

Grapes are a worldwide significant fruit, important for the wine industry, trade, and health benefits. Despite its significance, grape cultivation in India faces numerous biotic and abiotic challenges. Traditional breeding in this crop is very expensive, time-consuming and presents many technical obstacles. Since the plant has reproductive sterility, creating variability for these characteristics is possible only through induced mutation. The present study was undertaken to investigate the effect of gamma irradiation (0, 5, 15, 20 & 25 Gy) on morpho-physiological and biochemical traits of four in vitro raised wine grape genotypes (Pusa Navrang, H-76-1, Pearl of Csaba and Julesky Muscat). The gamma-irradiated shoot cultures were evaluated under in vitro and ex vitro conditions. All irradiation treatments affected growth traits. However, response was found to be genotypic and dose-dependent. The growth of irradiated cultures was stimulated at dose (5 Gy) less than LD50 dose, whereas, treatment of cultures with a dose higher than 15 Gy, reduced the growth and caused deformation in cultures. Based on plant growth and survival traits, 10 Gy was identified as LD50. Among the genotypes tested, Pusa Navrang exhibited good final recovery (10.43%) at high dose (20 Gy). However, genotype H-76-1 was found to be the most sensitive genotype to the higher dose (>15 Gy) of gamma irradiation. Amount of proline, total phenols and total sugars increased, while chlorophylls and carotenoids decreased irrespective of genotypes in response to gamma irradiation (>15 Gy). The results of present study will be very useful for future improvement of grapevine scion cultivars.