SEED GERMINATION, SEEDLING GROWTH AND VIGOUR OF PAPAYA UNDER NORTH EAST INDIAN CONDITION

Abstract

Papaya (Carica papaya L.) is a popular fruit of tropics and subtropics of the world. India is in the forefront of papaya producing nations. Papaya nursery is normally raised through seeds. There are improved varieties of papaya which are being used for commercial cultivation through out the country. But none of the varieties are commercially grown in the north eastern India due to undulating topography, high rainfall, poor transport, marketing facility etc. Hence, the present study was pursued in papaya with the objective of identifying cultivars suitable to north eastern region of India with better germination percentage, seedling growth and vigour. The experiment was executed at the Horticulture division of ICAR Research Complex for NEH Region, Barapani, Meghalaya during 2001-2002 with fourteen papaya cultivars comprising varieties and hybrids of red and yellow flesh types gathered from across the world. The indigenous collections comprised cultivars from Tamil Nadu Agriculture University, Coimbatore (Co-1, Co-2, Co-3 Co-4, Co-5, Co-6, and Co-7), cultivars from G.B. Pant University of Agriculture and Technology, Pant Nagar (Pant Papaya), Indian Agriculture Research Institute, New Delhi (Pusa Dwarf) and Indian Institute of Horticultural Research, Bangalore (Coorg Honey Dew and Pink Flesh Sweet) whereas Sunrise Solo, Thailand and Washington were the other varieties from foreign sources. The seeds were soaked overnight in different concentrations of gibberellic acid (0, 50, 100, and 150 ppm) and sown in perforated polythene bags containing potting mixture. The cultivars differed significantly with respect to their 1000 seed weight, seed germination, time taken for seed germination, seedling length including seedling vigour. Soaking the seeds with GA 3 had a significant effect in improving the germination percentage of papaya cultivars. Increasing the GA 3 concentration from 0 to 100 ppm significantly improved the germination (66.17%) over the control (42.40%) and above 100 ppm the seed germination decreased. GA 3 treatment had a favorable effect in hastening the germination of papaya and the time taken for germination was maximum in untreated control (31.86 days) whereas GA 3 at 100 ppm recorded the minimum period for germination (29.73 days). GA 3 treatment had a significant effect in enhancing the seedling length and it was maximum with GA 3 100 ppm (17.38 cm) as against control recording only 10.98 cm. It is concluded that the papaya varieties viz., Coorg Honey Dew, Pant Papaya, Co-2 and Co-7 possess better seed germination, seedling growth and vigour are highly suitable for commercial cultivation in north eastern region of India and their germination and seedling health can be improved by treating with GA 3 100 ppm.