SHARMA, D.P.THOKCHOM, ROCKY2017-06-142017-06-142014http://krishikosh.egranth.ac.in/handle/1/5810020061ABSTRACT The study entitled “Rejuvenation studies on growth,fruiting and fruit quality of apricot (Prunus armeniacaL.) cv. New Castle” was conducted on 25- years oldrejuvenated trees of New Castle apricot in the experimental orchard of the Department of Fruit Science, Dr. Y S Parmar University of Horticulture and Forestry, Nauni, Solan (H.P.) during 2013 and 2014. These experimental trees were given rejuvenation treatments (combination of 3 pruning severities and 3 levels of nitrogen) in the year 2011. The standard pruning was practiced afterwards but the combinations of different level of nitrogen in the experimental trees were applied. To ascertain the effect of rejuvenation treatment on tree vigour , fruiting, and productivity the study was further continued for another 2 years i.e. 2013 and 2014. T he experiment was laid out using Randomized Block Design consisting of 10 treatments replicatedthrice. The experiment comprised factorial combination of pruning severities (20%, 40%, 60% and heading back of main scaffolds) and, three levels of nitrogen (500, 625 and 750 g/tree). In all there were nine combinations of pruning intensities and nitrogen level treatments which wer e compared with control. The results revealed that maximum annual shoot growth (167.06 cm), tree spread (4.63cm), pruning wood weight (9.19kg/tree), leaf area (36.15cm 2 ), leaf chlorophyll contents (2.62mg/100g) and foli ar N (2.97%), Fe (248.26ppm), Mn (158.19ppm) and Zn (11. 77ppm) contents were higher in T 9 (60% heading back of scaffolds+750g Nitrogen). The various physico-chemical parameters such as fruit weight (26.59g), fruit volume (22.91cc), TSS (15.99 0 B), total sugar (9.84%), reducing sugar (3.70%), non-reducing sugar (6.61%), acidity (1.91% ) and fruit firmness (5.40kg/cm 2 ) were highest in T 7 (60% heading back of scaffolds+500g Nitrogen), whi le foliar P (0.247%), Ca (3.07%), Mg (0.92%) and Cu (14.56ppm) contents were higher in T1 (20% heading back of scaffolds+500g Nitrogen) in New Castle apricot under study.ennullThesis