314 INTRODUCTION Grape cultivation is considered to be an economic venture for the farmers due to its high monetary returns. Grape belongs to the family Vitaceae which consists of 12 genera and 600 species. Among these, Vitis vinifera produces the highest quantity of grapes either as pure vinifera or in the form of hybrids. Grape cultivation occupies an area of 140 thousand hectares with the production of 3,125 thousand MT (Anonymous, 2020a). ). In Punjab, area under grapes is 320 hectare with per annum production of 5,680 MT and productivity of 17,749 kg/ hectare. The recommended varieties of grapes by Punjab Agricultural University include Punjab Macs Purple, Superior Seedless, Flame Seedless, Beauty Seedless and Perlette (Anonymous, 2020b). Under North Indian conditions, one of the reasons of barrenness of the vines is excessive vegetative growth of the vines. Moreover, presence of excessive shoot vigour is detrimental to the plant growth because plant metabolites are used for vegetative growth which results in reduction in yield. So, it is important to decrease the vigour of vegetative growth without reduction in the shoot number. The vigour of vines can be controlled with either judicious pruning of canes or with use of growth retardants or both. Plant growth regulators are now considered to be new generation agrochemicals after pesticides, fertilizers and herbicides as these improve the source sink relationship thereby enhancing the translocation of photo assimilates and helping in better fruit set (Anayat et al 2020). In horticulture, plant growth retardants are used for the reduction of unwanted shoot length without afecting the productivity of the plants. Use of growth retardants is also a good practice in viticulture for the improvement of quality and productivity in grapes (Kumber et al 2017). Out of all the growth retardants used, the application of quaternary ammonium salt– chlormequat chloride is most common (Polyvanyi et al 2020). Since excessive vegetative growth hampers the fruit production, fruiting and fowering is successfully enhanced by the use of growth retardants. Cycocel can be used on vines as it is non-toxic, as well as it reduces the internodal length without causing change in leaf number and emergence of lateral shoots (Chougule et al 2008). Plant growth retardant Yield and Morphological Characters as Afected by Chlormequat Chloride Application in Grape Cultivar Punjab MACS Purple Jashanpreet Kaur*, Gagandeep Kaur, Kirandeep Kaur and N K Arora Department of Fruit Science, Punjab Agricultural University, Ludhiana, Punjab, India ABSTRACT The present investigation was carried out to evaluate the efect of growth retardant Chlormequat chloride (CCC) on morphological characters of grape cultivar Punjab MACS Purple. The foliar application of Chlormequat chloride (250, 500, 750 and 1000 ppm) was done at fve leaf stage while the control vines were sprayed with water only. Observations on vegetative growth were recorded at diferent growth stages. Maximum dose of Chlormequat chloride was found to be most efective in reducing cane length and internodal length while the same dose resulted in maximum cane diameter. There was reduction in leaf area as well as size while the efect on time of anthesis and trunk girth was less signifcant. It has been reported that yield and bunch weight was maximum with the application of 1000 ppm Chlormequat chloride followed by 700 ppm Chlormequat chloride. Key words: Grapes, Chlormequat Chloride, Vegetative Growth, Flowering, Yield. Corresponding Author email: jashanbrar9464@gmail.com J Krishi Vigyan 2021, 10 (1) : 314-320 DOI : 10.5958/2349-4433.2021.00119.7 J Krishi Vigyan 2021, 10 (1) : 314-320