K. S. Islam
Project Co-ordinator
AFIP-Intercooperation, H # 2FNE (D), R # 73G, Gulshan-2, Dhaka, Bangladesh
M. A. Rahim
Professor
Department of Horticulture, Bangladesh Agricultural University, Mymensingh-2202,
Bangladesh
S. Rehana
Assistant Professor
Department of Biotechnology and Genetic Engineering Discipline, Khulna
University, Khulna, Bangladesh
Onion, seed, pre-planting cold treatment, growth and development, flowering
Horticulture Farm, Department of Horticulture, Bangladesh Agricultural University, Mymensingh and Plant Genetic Laboratory of Bangladesh Institute of Nuclear Agriculture (BINA), Mymensingh
Variety and Species
This experiment was conducted to study the growth and development of onion plants with special emphasis on flowering. The study was carried out with a local cultivar of onion named ‘Taherpuri’. All the bulbs of Taherpuri were collected from Taherpur of Rajshahi District. The average bulb size for each experiment used was 10 ± 2 g except the experiment on bulb size. No split bulbs were used as planting materials. General characteristics of onion cv. Taherpuri: Bulbs are generally non-splitting, single, flask-shaped and good storage quality. Skin color is reddish brown; flesh color is yellowish white, highly pungent and high dry matter content. Leaves are moderately waxy, deep green, erect and tapering towards the end. Diameter of leaves and pseudostem are 1.00±0.25 cm and fairly resistant to Alternaria disease. Treatments: Pre-planting cold treatment plus a control, vis-à-vis i. Pre-planting cold treatment of bulbs at 7°C, ii. Pre-planting cold treatment of bulbs at 12°C, and iii. Bulbs at ambient temperature (30 ± 2°C).
Experimental design: The single factor experiment was conducted in the Randomized Complete Block Design with three replications. Dry sets of onion of about 10-12g (usual size grade for seed production) of a local cv. ‘Taherpuri’ were planted on 01 November. Pre-planting cold treatment was done for 45 days at 7 and 12°C using temperature- controlled incubator in the laboratories of Horticulture Department and BINA. Bulbs kept in ambient temperature (30 ± 2°C) were considered as control. Parameters recorded: Periodical harvest of 5 hills was done at 7 days interval and following parameters were recorded very specifically days required to 80% emergence of bulb, percentage of devernalized bulb, plant height, number of green leaves per hill, length of leaves per plants, individual leaf length, fresh weight of leaves, duration of green leaf production, fresh weight of bulbs, fresh weight of roots, number of tillers per hill, number of flower stalks per hill, length of flower stalks per hill, stages of inflorescence development, growth of flower stalk, time of opening the bract, opening of flower in main umbel, number of flowers per umbel, commencement of fruit setting, the stage of ripening of fruits (number of fruit set and percentage of fruit set), the period of seed harvest days required for first visible bolting, growth and maturity of flowering stalk, anthesis period, maturation of fruits and harvesting of dry umbel.
Intercultural operations were done as and when required. The crop was harvested on different dates in different plots when 75% of the tops in each plot had fallen over. Five hills were randomly selected in each plot to record data on different yield contributing characters and seed yield. Data were statistically analyzed with a computer following MSTAT programme.
Progress. Agric. 21(1 & 2): 47–55, 2010 ISSN 1017-8139
Journal