STANDARDIZATION OF NURSERY PRACTICES FOR PRODUCTION OF QUALITY PLANTING STOCKS OF MAHOGANY (Swietenia mahagoni) Linn Jacq.

The present investigations entitled “Standardization of nursery practices for production of quality planting stocks of Mahogany (Swietenia mahagoni Linn. Jacq.” were carried out in the instructional field of the Department of Forestry, Uttar Banga Krishi Viswavidyalaya, Pundibari, Cooch Behar, West Bengal during the year 2014 2015. The experimental site lies in the plains of Terai zone of West Bengal at an elevation of 43 m above mean sea level which embodies sub-tropical humid climate. Germination was significantly different (p=0.05) among all pre-treatments. It was found that seeds soaked in thiourea 500 ppm for 24 hours gave the maximum (85.0%) germination percentage followed by 100 ppm kinetin for 24 hours (82.0%) and cold water soaking for 48 hours (81.0%) which was statistically at par with each other whereas the control showed only 71% germination. Pre-treatment of seed with sodium fluoride always gave average lowest germination among all pre-treatments. The average maximum germination value (4.04) was recorded in the seeds soaked with thiourea 500 ppm for 24 hours followed by 100 ppm kinetin (3.82). The germination value 2.95, 3.21 and 3.53 was observed in seeds pretreated with cold water soaking for 12, 24 and 48 hours respectively. The minimum value (0.58) was noticed in the seeds pre-soaked with 1000 ppm sodium fluoride for 24 hours. Highest and lowest mean germination time (37.68 and 30.64 days) was noticed in 1000 ppm of sodium fluoride and 500 ppm of thiourea indicating that the thiourea treatment takes lesser time to germinate. Seeds treated with 500 ppm of KNO3 reached RG50 faster (30.80 days) than other treatments closely followed by seeds soaked with 100 ppm of KNO3 (31.60 days). Seeds treated with 1000 ppm of thiourea took a much longer time to reach RG50 (37.20 days). Though seeds soaked with 1000 ppm of sodium fluoride showed 32.60 days to reach RG50 but this treatment could never reached 50% germination. Over all, total seedling length was improved in pretreatment seeds of mahogany. seeds soaked with 1000 ppm sodium fluoride gave the lowest seedling length (25.71 cm) whereas the maximum seedling length was obtained from GA3 250 ppm treated seeds (32.01 cm) followed by cold water for 48 hours (31.91 cm), GA3 1000 ppm (31.82 cm) and kinetin 100 ppm (31.58 cm). Seedling vigour index under different pre-treatments ranged from 822.59 to 2606.66. Seedling vigour index represents the potential level of activity and performance of seed during germination and seedlings growth which was found higher (2606.66) with thiourea 500 ppm followed by kinetin 100 ppm (2589.41); cold water soaking for 48 hours (2584.16) and GA3 250 ppm treated seed (2539.68). The seedlings used in the fertilizer experiment were not significantly different in their initial growth. All growth parameters were measured at four different intervals for subsequent growth prediction. Finally data of 240 days were considered for describing the result. Application of 200 kg of N/ha (T4) showed the best result in respect to collar diameter, height, root, shoot and leaf biomass at 60 days of growth. After that seedlings in T5 (N300) showed the best results in all growth parameters. SQ values for mahogany seedlings ranged from 5.43 to 5.60 among the treatments. SQ values among the application of fertilizer crossed limit 6.0 at 240 days of growth which was not advisable for quality seedlings. DQI ranged from 6.29 to 10.86 at 240 days of the growth period. The seedlings of T5 (N300) and T1 (N0) showed the maximum (10.86) and minimum (6.29) quality index respectively. Plants developed in the application of nitrogenous fertilizer showed the greatest values for QI up to the application of 300kg of N/ha. This suggests good potential for survival and growth in the field.