Arora, N.K.Vikrant2019-11-162019-11-162019http://krishikosh.egranth.ac.in/handle/1/5810135471The present investigations entitled „Effect of supplemental foliar application of potassium on yield and fruit quality of winter guava (Psidium guajava L.)‟ was carried out at Fruit Research Farm and PG Laboratory, Department of Fruit Science, Punjab Agricultural University, Ludhiana and at the Regional Fruit Research Station, Bahadurgarh during the year 2017-18. At Ludhiana experiment was conducted on 5-years-old-tree of guava cv. L-49 and at Bahadurgarh experiment was conducted on 8-years-old-tree of guava cv. Shweta. The trees were sprayed with various doses of KNO3 and K2SO4 (1.0 %, 2.0 % & 3.0 %) during the first week of August, September and October. Maximum per cent increase in tree height (9.42 % in L-49 and 9.36 % in Shweta) and canopy volume (20.34 % in L-49 and 19.99 % in Shweta) was observed with three sprays of KNO3 @ 3 per cent. Likewise higher shoot length (36.05 cm in L-49 and 34.62 cm in Shweta) was recorded in treatment (T6) i.e three sprays of KNO3 @ 3 per cent as compared to control. The foliar application of KNO3 @ 3 per cent thrice had significantly higher fruit weight (224.13 g in L-49 and 230.13 g in Shweta), fruit size i.e fruit length (8.1 cm in L-49 and 8.1 cm in Shweta) and fruit breadth (7.2 cm in L-49 and 7.3 cm in Shweta) and yield (59.17 kg in L-49 and 48.90 kg in Shweta) which was statistically at par with treatment (T12) in which three superimposed foliar application of K2SO4 was given at monthly interval. Whereas, fruit firmness (6.47 kg/cm2 in L-49 and 6.53 kg/cm2 in Shweta) was observed higher in trees sprayed with KNO3 @ 3 per cent twice. Fruit colour was measured with hunter colour lab and value of „l‟, „a‟ & „b‟ were recorded. Foliar application of K2SO4 @ 1 per cent twice showed improvement in fruit colour as compared to other treatments. Fruit quality characteristics viz. Total soluble solids content (TSS), TSS/acid ratio and total sugars were also enhanced with two and three superimposed sprays of potassium over untreated trees however fruit acidity was not affected significantly by potassium salts. Leaf N and K contents were significantly higher with foliar sprays of KNO3 and K2SO4 over control. Higher shelf life was observed with three foliar application of KNO3 @ 3 per cent and parameters viz. Physiological loss in weight, TSS, Acidity, Fruit Firmness, organolaptic score and fruit colour were significantly improved with potassium salts. The three spray of KNO3 at 3 per cent was found to be the best in terms of improving fruit yield and production of good quality fruits with longer shelf life.ennullThesis