Gagandeep KaurJeevan Jyoti2021-03-192021-03-192020Jeevan Jyoti (2020). Effect of Hydrogen cyanamide and Hexanal on maturity and quality in grape cv. Flame Seedless (Unpublished M.Sc. thesis). Punjab Agricultural University, Ludhiana, Punjab, India.https://krishikosh.egranth.ac.in/handle/1/5810162655The investigation was carried out during the year 2019 on 14 year old grapevines to study the “Effect of Hydrogen cyanamide and Hexanal on maturity and quality in grape cv. Flame Seedless” at Fruit Research Farm, Department of Fruit Science, Punjab Agricultural University, Ludhiana. Hydrogen cyanamide (1.5%) was applied just after pruning when the vines were under dormant condition. Two superimposed sprays of hexanal formulation (1.5, 2 & 2.5%) were given 30 and 15 days prior to the time of harvesting. Bunch thinning was followed in all the treatments where 75-80 bunches were retained at time of bunch emergence except control. Effect of hydrogen cyanamide and hexanal formulation was evaluated in combination with girdling (done at the pea stage of berry) and ethephon (400 ppm), sprayed at the veraison stage of berry development. Results showed that hydrogen cyanamide (1.5%) advanced the bud burst, flowering and ripening by 25, 17 and 8 days respectively as compared to control. However, earliest ripening (by 9 days) was induced in the clusters treated with hydrogen cyanamide @ 1.5 % + ethephon @ 400ppm. Uniform color development with maximum TSS (18.7%), total sugars (16.86%), anthocyanins (48.45mg/l), juice pH (3.68) and minimum acid content (0.55%) was observed in berries treated with hydrogen cyanamide in combination with ethephon. Also, hydrogen cyanamide increased the bud content of IAA and GA3 on each date of sampling relative to untreated buds. Hexanal application @ 2 % or 2.5% along with hydrogen cyanamide adjudged as the best pre-harvest treatment in retaining the berry firmness whereas ethephon treatment reduced the firmness of berry. Foliar spray of hydrogen cyanamide (1.5%)+ Hexanal 2.5 % +girdling significantly improved the average yield (28.39 Kg/ vine) and quality of grape clusters viz. bunch weight (368.54 g), bunch size (24.56 cm × 14.45 cm) and berry weight (2.83 g), and TSS: acid ratio (30.00). However the results of hexanal dose 2.5 and 2.0 per cent were at par for these parameters, thus hydrogen cyanamide (1.5%)+ Hexanal 2.0 % +girdling was found to be best for inducing earliness in grapes without compromising the quality of berries.EnglishThesis