Standardized Protocol for In Situ and In Vitro Maintenance of Newly Developed Parthenocarpic Gynoecious Cucumber Inbred

Abstract

New parthenocarpic gynoecious cucumber line 'PBRK-11' was developed, morphologically characterized and observed that its fruits were dark green, cylindrical, seedless, bitter free, and long (19-22 cm). Besides, different chemicals {GA3, AgNO3, and [Ag(S2O3)2 -3 ]} having different concentrations were used for altering the sex expression of parthenocarpic gynoecious line to induce male flowers for seed production. Analysis of variance showed that chemical applications significantly affect the male flower induction and plant mortality percentage of parthenocarpic gynoecious cucumber inbred. Application of silver thiosulphate @ 250 ppm induced maximum number of male flowers per plant, minimum plant mortality percentage and induced male flowers for longer duration in parthenocarpic gynoecious plants when sprayed at 3-4 leaf stage at weekly interval for three weeks. Besides, in vitro protocol was standardized to maintain it. Shoot tip explants cultured on half MS media showed higher regeneration rate of 53% with highest shoot initiation response in 32 days followed by M5 [MS + BAP (1.0 mgL -1 ) + Kinetin (1.0 mgL -1 )] media with 48% regeneration. Root induction rate (80%) was high in MS media supplemented with IAA (1.0 mgL -1 ). The parthenocarpic gynoecious expression was found to be stable in tissue culture regenerated progenies.