Effect of growth retardants on growth, flowering and physiological characteristics of olive cultivar Leccino under rain-fed conditions of Himachal Pradesh, India

A field experiment was carried out during two consecutive years to ascertain the influence of paclobutrazol and cycocel on growth, cropping and water relations in olives. The trial was undertaken at the Olive Development Centre, Kigus, Mandi, Himachal Pradesh. In this experiment eight treatments viz., PP₃₃₃ at 2 and 4 g a.i. tree⁻¹ applied once in November or December as soil drench and cycocel at 1000, 2000 and 3000 ppm applied as foliar spray each year, two weeks after flowering to the trees of olive cultivar Leccino, with three replications in a randomized block design. Growth retardants have a great potential on controlling the growth, water relations and improving cropping parameters in rain fed conditions. During the study, PP₃₃₃ at 4 g a.i tree⁻¹ when applied in November as soil drench decreased growth (15.69 cm), length of internodes (1.84 cm), leaf area (4.60 cm²), stomatal size (13.61 μm), water potential (−15.69 bar), transpiration rate (0.160 m mol m⁻² s⁻¹), endogenous GA₃ (9.61 hg/g fresh weight), stomatal conductance (1.51 mol m-2s-¹) and increased leaf thickness (0.62 cm), leaf chlorophyll content (3.05 mg/g fresh weight), photosynthesis (24.62 μ mol m-² s⁻¹), osmoprotectants that is. Proline (2717 μg/g) and ABA(60.74 (hg/g fresh weight), flowering intensity (0.65%) and fruit set (7.57%), and thus might be helpful in mitigating water stress under rain fed conditions.