Efficacy of hybrid seed production through natural pollinators employing male sterility: Case study of ridge gourd [Luffa acutangula (Roxb.) L.] CGMS system

Abstract

Potential of natural pollinators and manually assisted pollination for producing F1 hybrid seeds of ridge gourd hybrid ‘KRH 1’ was evaluated under open field condition for two seasons by growing male sterile line (KAU-LA-MS-101) and monoecious male fertile line (LA-102) in alternate rows. Investigation was carried out at the Department of Vegetable Science, College of Agriculture, Vellanikkara, Thrissur, India. Species diversity of the pollinators, peak foraging time of the pollinators, number of floral visits by pollinating bees and number of bees visiting a flower during stigma receptivity were recorded. Nectary glands of male and female flowers of KAU-LA-MS-101 and LA 102 were measured. Seed yield and seed quality related traits were also recorded following standard protocol. Male sterile plants produce small male flowers with tiny nectary glands when compared to that of LA- 102, but female flowers of male sterile line have larger nectary glands. Stingless bee (Tetragonula sp.), was the pollinator observed in the field during anthesis time with peak activity after 5.30 pm. Number of fruits, number of seeds per fruit and average seed weight were significantly different between male sterile line and monoecious male fertile line LA-102. Pollination efficiency of bees found to be high when compared to manual hands in terms of quality of seeds produced from male sterile plants. However manual hands proved to be better for inducing more number of seeds per fruit. Total seed yield per plant depends on the total number of fruits developed and pollination by bees induces the development of more flowers to maturity, thereby ensuring competitive seed yield. Seed yield per plant exhibited significant positive correlation with seed length, shoot length, root length, fresh weight, vigour index I and germination velocity index. Present investigation revealed the potential of male sterile line developed in ridge gourd for hybrid seed production. Alternate planting of fertility restorer line with the MS line and allowing open pollination with the assistance of bees will reduce the labour charge involved in hybrid seed production and quality seed can be made available at a competitive rate.