S K BHARDWAJLEKHIKA PARIHAR2023-12-262023-12-262023-10-07https://krishikosh.egranth.ac.in/handle/1/5810204503ABSTRACT The present investigations entitled “Phenology of stone fruits and its relationship with environmental factors in mid hills of mid hills” was conducted in the Department of Environmental Science, Dr YSP University of Horticulture and Forestry, Nauni- 173230 Solan HP during 2020-22. The study was conducted to determine the influence of changing environment of different altitudinal gradients in mid hills of Himachal Pradesh on crop phenology of major stone fruits. To accomplish objectives of the study the major stone fruits namely, apricot, peach and nectarine growing at two altitudinal gradients viz.,1200-1400 and 1400-1600 m amsl having different environmental conditions including edaphic factors were considered. At each selected elevation five commonly growing varieties namely New Castle of apricot, Red Gold & Sun Crest of peach and Glo Haven & Silver King of nectarine were selected at two different sites of each gradient. In the region stone fruits exhibited variations in attaining phases from pink bud to fruit maturity at both the altitudinal gradients. The cultivar New Castle of apricot plants took maximum of 114.4 days to complete all phases up to maturity. In case of peach plants cultivar Red Gold and Sun Crest took 112.6 and 111.1 days to complete their phenological cycle. Whereas, the Silver King and Glo Haven of nectarine fruit plants took 110.3 and 108.6 days to complete the cycle up to maturity of fruits. Among all the stone fruits, apricot cultivar New Castle accumulated the highest GDD of 731.4oC days to complete the phases up to fruit ripening. The highest accumulation of GDD of apricot was followed by peach cultivars namely Red Gold and Sun Crest with values of 723.3 and 718.5oC days. Whereas, the cultivars Glo Haven and Silver King of nectarine fruit plants accumulated lowest GDD of 708.3 and 715.3 oC days to complete all the phenophases. The accumulation of GDD increased with elevations and on an average all the stone fruits accumulated 10.6oC days at 1400-1600 m amsl higher than at lower elevation. The study indicated that the stone fruits chilling requirement ranges from 238.2 to 301.7 CH in the region. Among all the stone fruit plants the highest CU of 301.7 CH accumulated by New castle of apricot to break dormancy and achieve pink bud stage. The Red Gold and Sun Crest cultivar of peach plants accumulated effective CU of 268.4 and 250.5 CH to break the dormant bud. The cultivars Glo Haven and Silver King of nectarine plants accumulated 238.2 and 243.7 CH to attain pink bud stage after dormancy. The HTU accumulated ranged from 5388.4 to 5530.1 oC day hrs in the region. Among all fruits the highest HTU of 5530.1oC days hrs. accumulated by New Castle to complete the phenological cycle. The Red Gold and Sun Crest cultivar of peach and Glo Haven and Silver King of nectarine accumulated HTU of 5427.6, 5392.1 and 5388.4 and 5418.9 oC day hrs respectively to attain all phenological stages. The HTU accumulation by the plants decreased with increased elevation as it was 5103.0 oC days hrs at 1400-1600 m amsl and 5759.8 oC days hrs at lower altitudinal gradient of 1200-1400 m amsl. The soils of 1400-1600 m amsl under stone fruits exhibited higher soil moisture, available NPK and micronutrients namely, Fe, Mn, Cu and Zn with respective ranges of 27.9- 30.1%, 417.5- 467.5 kghg-1, 29.5- 38.0 kghg-1, 187.5- 290.0 kghg-1, 12.9-20.0 mgkg-1, 0.82- 1.34 mgkg-1,1.43- 2.25 mgkg-1,10.1- 14.4 mgkg-1 whereas, at lower elevations the values of these parameters ranged from 26.28- 28.05%, 409.5- 458 kghg-1, 27- 40 kghg-1, 180.5- 281 kghg-1, 12.61- 17.29 mgkg-1, 0.77- 1.29 mgkg-1, 1.33- 2.19 mgkg-1, 9.78- 13.51 mgkg-1. The altitude wise average temperature was in order of 21.1°C (1200-1400 m amsl) > 20.0°C (1400-1600 m amsl) during first year (2020-21). Whereas, during second year (2021-22) the average temperature was in the order of 21.9°C (1200-1400 m amsl) > 20.8°C (1400-1600 m amsl). At lower elevation on an average 0.6-1oC temperature was higher than the higher elevation. Among all the stone fruits, apricot cultivar New Castle exhibited advancement of 6-7 days in attainment of phenophases at lower elevation of 1200-1400 m amsl. While, the cultivars Red Gold and Sun Crest of peach and Glo Haven and Silver king of nectarine exhibited advancement of 7-8 days at low altitudinal gradients. The instability index indicated altitude wise irregularity in the range of 13.6 to 14.8 % to attain various phenological stages which decreased with increasing elevations. In stone fruits the syrphids was most dominant insect in the region followed by Apis cerana, other hymenopterans, Apis mellifera and other insects with respective values of 12.68, 10.94, 3.10, 2.22, 0.85 m-2 5 min-1 afternoon at higher elevation of 1400-1600 m amsl. Whereas, their order was 12.11 > 9.56 > 2.66 > 2 > 0.65 m-2 5 min-1 at lower elevation. The study inferred that the altitudinal wise significant variation in environmental conditions which might have influenced phenological cycle of stone fruit plants and their GDD and HTU accumulation as well as pollinator insect visitation. The altitude wise variation in their parameters can be exploited for planning judicious marketing of fruits and identification of new areas of their cultivation. The phenophase wise pattern at different altitudinal gradients under influence of varied temperature and other edaphic factors also indicated that how climate variability may influence the crop production in the region in coming years and hence there is urgent need to enhance climate resilience of these important fruits by managing the edaphic factors on sustainable basis so that stone fruit crops productivity can be enhanced and crop harvest and marketing may be planned judiciously in the region.EnglishThesis