Abstract
Eleven experiments were conducted at Domar Farm, Nilphamari and HADS Farm, Thakurgaon during 1999-2000 to 2001-2002 seasons in order to define and standardize a package of technology for the production of hybrid TPS under Bangladesh conditions using a photoperiod extended up to 16 hrs with the help of artificial light. The area of study covered standarsization of NPK dose, plant population, number of main stems per hill, time of planting of female parent and use of plant growth regulator in relation to hybrid TPS production. The results of 4 NPK trials demonstrated that different doses of nitrogen, phosphorus and potassium had significant effect on vegetative growth, flowering characteristics, yield components and yield of TPS. It was noted that different levels of N and P2Os had marked positive influence on the yield of berries as well as seed. Whereas, K2O had little effect. Out of 27 doses tested in the first NPK trial, conducted in Domar Farm, the 215-185-185 kg N, P2O5, K2O/ha dose gave the highest yield of TPS (128.47 kg/ha) with a net return of Tk. 10,53,610/ha. And out of 18 doses tested in the second NPK trial, also conducted in Domar Farm, the 215-235- 250 kg N, P2O5, K2O/ha dose gave the highest yield of TPS (146.59 kg/ha) with a net return of Tk. 13,07,810/ha. In the third and fourth NPK trials, conducted in Domar and HADS Farms, the highest TPS yields (153.63 kg and 160.19 kg/ha), net returns (Tk. 14,06,476 and Tk. 14,92,168/ha) and BCR values (2.34 and 2.40) were found at both locations under the 215-185-250 kg N, P2O5, K2O/ha dose and application of NK fertilizers in three equal splits. The results of 2 plant spacing experiments demonstrated that the widest spacing (70 x 25 cm) allowing a population of 57,142 hills/ha with plants pruned to 2-3 main stems per hill resulted high in TPS yield (110.31 kg/ha). The results of 2 planting date trials revealed that for higher yield of good quality hybrid TPS under the north-western Bangladesh conditions, 5-25 October was the best time for planting of mother tubers. The results of 2 plant growth regulator trials showed that the application of 200 ppm GA3 on flower buds and inflorescences had significant positive effect on flowering, yield components and TPS yield over control. The results of another growth regulator experiment revealed that application of either 100 ppm GA3 or 50 ppm GA3 + 50 ppm BA had positive significant effect on production and retention of flowers in the male parent over control.