Effect of bulb size on quality seed production of onion in Bangladesh

A study was conducted in the experimental farm of Bangabandhu Sheikh Mujibur Rahman Agricultural University (BSMRAU), Gazipur, which is situated at 24.040 N latitude and 90.40 E longitudes with an elevation of 8.4 meter from the sea level and in the 28th Agro ecological Zone (AEZ) during the year 2011 to 2012. The purpose of the study was to evaluate the effect of bulb size on quality seed production of onion. Onion variety “Taherpuri” with three bulb sizes (4g, 8g and 12g) had a remarkable impact on seed yield, yield attributes and seed quality. Plant height, number of leaves per plant, length of scape, number of umbles per plant, umble diameter, seed yield per plant, germination percentage and electrical conductivity were positively influenced by bulb size of onion. It was revealed that the big bulbs (12 gm) gave larger numbers of umbels per plant than the umbels grown from the medium (8 gm) and small (4 gm) ones. Small bulbs gave lowest umbel diameter with smaller inflorescences than the medium and large ones. The bulb size also did not affect seed yield per one seed stalk, but it did affect the seed yield obtained from the entire plant, which was bigger for plants grown from large bulbs in comparison with the small ones. Bulb size, however, showed significant effect. Thus, as bulb size increased, the number of flower stalks per bulb increased, as did in seed production per plant and per hectare.