94 Sapota (Manilkara achras (Mill) Fosberg) is an important evergreen, tropical fruit crop commonly known as chiku in India. It belongs to the family sapotaceae. It is commercially grown in south Indian states like Karnataka, Gujarat, Tamil Nadu, Maharashtra, West Bengal and Orissa. It is also grown successfully under sub-tropical conditions in north India states like Punjab and Haryana. In Punjab, sapota is successfully grown in the sub-mountainous zone including Gurdaspur, Hoshiarpur, Pathankot, Roopnagar, Mohali and Patiala districts (Anon 2018). Sapota is a good source of digestive sugars which ranges from 12-18% and also contains appreciable amount of fat, proteins, fbre and some minerals like calcium, iron and phosphorous (Shanmugavelu and Srinivasan 1973). The area under sapota cultivation is increasing day by day in India due to its continuous fruiting habit throughout the year and its hardy nature against many biotic and abiotic stresses (Chundawat 1998). Sapota produces fowers throughout the year but all the fowers do not develop into fruit and reach maturity. In Punjab, fowering occurs in sapota in April-May and July-August. The fowering of July-August results in more fruit set and main crop is harvested during May-June which fetches good price in market. To improve quality of fruits and increase the productivity of existing sapota orchards use of the different growth regulators is one of the best method. Enhanced fruit quality with the application of growth regulators is due to metabolic changes in the fruits leading to conversion of complex polysaccharides into simple sugars. Moreover, the exogenous application of NAA during fowering caused the cell elongation of vacuoles and loosening of cell wall after increasing its plasticity (Rathod 1977). Kalipatti is most popular among various cultivars of sapota and is used for table purpose and moreover found to be the highest yielding among the all other tested cultivars in India (Chundawat and Bhuva 1982). Fruits are oval in shape, gritty fesh, good quality with about 1-4 seeds and average yield of about 166 kg/ tree. Plant growth regulators like auxins, gibberellins have been reported to increase fowering, fruit set, fruit retention, fruit development and quality of several fruit crops (Chacko et al. 1972, Das and Mahapatra 1975). Under north Indian conditions, no information is available on the effect of plant growth regulators on quality and yield of sapota. Therefore, the present research work was carried out with an objective to study the effect of auxin and gibberellic acid on fruit yield and quality of sapota cv. Kalipatti. MATERIALS AND METHODS The present study regarding assessing the effect of auxins and gibberellins on yield and quality of sapota cv. Kalipatti was carried out at Fruit Research Station, Bahadurgarh (Patiala) during the year 2016-17. Eight year’s Indian Journal of Agricultural Sciences 89 (5): 842–5, May 2019/Article Infuence of different plant growth regulators on yield and quality of sapota (Manilkara achras) cv. Kalipatti NARPINDERJIT KAUR 1 and HARSIMRAT K BONS 2 Punjab Agricultural University, Ludhiana, Punjab 141 004 India Received: 4 July 2018; Accepted: 27 November 2018 ABSTRACT The present study was carried out at Regional Fruit Research Station, PAU, Ludhiana during the year 2016–17 to investigate the infuence of different plant growth regulators on yield and quality of sapota Sapota (Manilkara achras (Mill) Fosberg) cv Kalipatti. Eight year’s old uniformly grown Kalipatti sapota plants planted at 9×9 m spacing were sprayed with plant growth regulators NAA @ 50,75,100 and 125 ppm and GA 3 @ 25,50,75 and 100 ppm keeping two controls, one as water spray and second without any spray in the month of May, August and September during fowering and at pea stage. Sapota fruits were analyzed for physical and chemical parameters. It was concluded that application of NAA @ 125 ppm during fowering and at pea stage resulted in improved fruit quality in terms of maximum fruit size, fruit frmness (4.01 kg/cm 2 ), pulp weight (70.55 g) fruit weight (88.33 g), reducing sugars (9.44%), total sugars (14.39%), TSS (22.2%) with low acidity (0.16%) and higher fruit yield (37.13 kg/tree). Key words: GA 3 , Growth regulators, Kalipatti, NAA, Plant Growth Regulators, Quality, Yield 1 M Sc Student (pinder20792@gmail.com), 2 Assistant Horticulturist (harsimratpau@gmail.com), Department of Fruit Science. https://doi.org/10.56093/ijas.v89i5.89667