The ultra-short maturity class rice (Oryza sativa L.) matures in approximately 80 days from sowing and can effectively avoid droughts and floods without impairing grain yield if its field crop duration (FCD) that requires water supply is kept to a minimum. The objective of the present work was to study the influence of cultural practices, namely stand establishment, top dressing fertilization, irrigation and the growing season on the duration of the crop in the field that requires water supply and on grain yield of a newly developed rice variety (Bg 250) of the ultra-short maturity class. Bg 250 gave consistently higher yields in the dry season. Furthermore, FCD that requires water supply could be minimized to about 57-59 days depending on the season, without impairing grain yield, by transplanting 12 day old seedlings at the rate of 3 seedlings/ hill when coupled with termination of irrigation at 14 days after 50% heading. Reduction in the rate of top dressing fertilizer by half of the recommended rate did not influence FCD that requires water supply, but it reduced grain yield in the dry season which was not the case in the wet season. Therefore, in the low yielding wet season, Bg 250 can be cultivated at comparatively lower cost by reducing the rate of top dressing fertilizer to 50% of the recommended rate.