Induced Polyploidy via Colchicine Treatment Increases Flower Size and Fruit Weight in Cape Gooseberry (Physalis peruviana L.)

An induced polyploid plant through colchicine treatment offers probably the best scope for improvement in flower size and fruit weight. Thus, in the present study, an attempt was made to induce polyploidy in Cape gooseberry using colchicine with the objective of creating more genetic variability. The colchicine concentrations were used as 0.10% (C₁), 0.20% (C₂) and 0.40% (C₃) for the duration 12 (H₁), 24 (H₂) and 36 (H₃) hours for each concentration with seedling apex dip method (M₁), cotton plug method (M₂) and lanolin paste method (M₃). The plants treated with 0.10% of colchicine by cotton plug method for 12 h showed the better performance during the years 2017-2018 and 2018-2019 in respect of more delay in the flower bud emergence (54 d and 53 d from the date of transplanting), anthesis (19 d and 20 d from the first appearance of bud to full anthesis of flower) and fruit setting (8.00 d and 9.00 d from the date of anthesis), bigger flower size (2.93 cm² and 3.00 cm²) than the untreated plants. The lower percentage of pollen viability (40.33% and 40.67%) was noticed in the same treatment in comparison to control (70.33% and 72.33%). The fruit maturity was also extended (59 d and 60 d from the date of fruit set) with bigger sized fruits (length: 2.53 cm and 2.57 cm, breadth: 2.27 cm and 2.33 cm) as well as more fruit weight (8.70 g and 8.33 g) by the application of colchicine at 0.10% with cotton plug method for 12 h. On the basis of results obtained, the application of colchicine at 0.10% for 12 h duration with cotton plug method was found to be the best and effective treatment for induction of polyploidy as well as more flower size and fruit weight in Cape gooseberry.