Production potential of olive cultivars at different maturity stages and optimization of propagtion techniques

Abstract

Production potential of olive cultivars (Frontoio, Manzanilla, Ottobratica, Pendolino and Picual) at different maturity stages (Lemon green, Semi-ripe and Ripe) was investigated and propagation techniques through cutting and air-layering were optimized during 2014 and 2015 under irrigation condition at Olive Model Farm Sangbhatti, Mardan-Pakistan. Flowering date was taken as base line for phonological attributes. Cultivar Pendolino started early flowers opening on 12th April and took more days (9.50) upto fruit set, while less days (6.33), started from 18th April were noted for Ottobratica. Manzanilla and Picual attained lemon green maturity for harvesting after 193.50 (25th October) and 192 (22nd October) days respectively, while 202.17 (2nd November) and 201.33 (1st November) days were taken by these cultivars to reach semi ripe stage and 214.17 and 210 days to ripe stage of harvesting respectively. Frontoio, Ottobratica and Pendolino attained semi ripe stage after 180.17 (11th October), 184.50 (20th October) and 193 (22nd October) days respectively, while 188 (19th October), 195 (30th October) and 203.67 (2nd November) days were taken by these cultivars to attain ripe stage of harvesting. The cultivar Manzanilla produced heavy (4.34 g) fruits; however large sized (4.48 cm3) fruits having more pulp:stone (4.94) were yielded by Picual. The oil extracted from Manzanilla cultivar has less peroxide value (3.21 meq kg-1), more Phenol (616.67 mg kg-1) and chlorophyll (4.58 mg L-1). High fruit yield (35.81 kg tree-1) with more oil percentage (14.66%), less free fatty acid (0.43%) and more carotene (2.70 mg L-1) were determined in the oil extracted from fruits of Frontoio. The values of the quality attributes were within the range of IOC trade standards (IOC, 2003) of extra virgin olive oil category, with the exception of free fatty acid (%) recorded in the oil extracted from fruits of Ottobratica, harvested at ripe stage of maturity that fulfilled the requirement of virgin category. Yield and yield components enhanced from lemon green to semi-ripe and ripe stage of harvesting. Free fatty acid (0.25%) and peroxide value (3.04 meq kg-1) were lower and total phenols were higher (530 mg kg-1) in the oil extracted at semi-ripe stage, while high free fatty acid (1.50%), peroxide value (4.43 meq kg-1) and low phenol (361.67 mg kg-1) were determined in the oil extracted from fruits harvested at ripe stage. The chlorophyll and carotenoids contents significantly decreased with fruit ripening ranged from 4.99 to 2.41 mg L-1 and 3.17 to 1.49 mg L-1 respectively from lemon green to ripe stages of harvesting. The multiplication of olive cultivars (Frontoio, Manzanilla, Ottobratica, Pendolino and Picual) through cuttings and air-layering was optimized in sequential experiments. Semi hardwood cutting proved to be the root generative type. The cuttings of Frontoio produced highest number of roots (10.56) and root length (6.61cm), followed by the cuttings of cultivar Manzanilla that generated 8.17 numbers of roots with 6.06 cm length, while less number of roots (5.50) was produced by cuttings taken from cultivar Pendolino. The sapling of Ottobratica produced through cuttings accomplished 23.64% survival, followed by survival percentage (19.48 and 15.7%) noted in the saplings of cultivar Manzanilla and Frontoio respectively, while less survival percentage (9.73%) recorded in saplings of Pendolino. The semi hardwood cuttings of olive cultivars treated with 3000 ppm IBA solution enhanced rooting. The cuttings of Frontoio produced maximum number of roots (14.50), root length and weight (8.12 cm and 5.53 g respectively), followed by cuttings of Manzanilla which generated 12.04 number of roots with 7.19 cm length while less number of roots (8.57), root length and thickness (4.33 cm and 3.94 mm, respectively) were produced by Pendolino. Manzanilla attained 43.05% survival followed by Frontoio with 40.38 % survival, while less survival (23.24 %) was recorded in plants of Pendolino. The time interval of mid August proved to be most favorable time for air-layering in terms of rooting percentage (42.40 %), number of roots (4.37), root length (4.35 cm), weight (1.68 g), number of re-sprout (3.67) and shoot length (5.61 cm) while late and early layering responded poorly to all the studied attributes. The layering treated with 2000 ppm took less days (35.13) to root appearance, accomplished 72.00% rooting success, generated 5.85 number of roots with 6.65 cm length and 2.47 g weight and 4.89 number of re-sprout and 7.00 cm shoot length. The untreated layering took maximum days to root appearance (50.40), attained less rooting percentage (47.07%). The layering of Manzanilla generated early rooting and took less (36.00) days for root appearance, accomplished high rooting percentage (77.47 %), produced more (6.38 number) and lengthy (7.03 cm) roots and more (5.57) re-sprouts, followed by layers of Frontoio that took 38.8 days for root appearance, attained 65.73% rooting success and produced 5.69 number of roots with 6.14 cm length while the layers of Pendolino took maximum days for root appearance (48.40) and accomplished 48.27% rooting. It is concluded that the olive cultivars Frontoio, Manzanilla and Picual were found high yielding with good oil recovery of extra virgin oil grade. Pendolino is marginally accepted, while the performance of Ottobratica was not satisfactory under the agro-climatic conditions of Sangbhatti, Mardan. The olive fruits harvested at semi ripe stage provided equilibrium in yield, oil recovery and quality attributes. The semi hard wood cuttings treated with 3000 ppm IBA solution developed profuse root and shoot systems in olives cultivars. The plants of Frontoio, Manzanilla and Pendolino when air-layered during mid-August, treated with 2000 ppm IBA solution attained high rotting percentage. Ottobratica produced maximum number of roots when air-layered during mid July, treated with 1000 ppm IBA and Picual during late July, treated with 2000 ppm IBA solution.