Studies on Parental Synchronization in Flowering for Hybrid Seed Production in Onion (Allium cepa L.)

An experiment was conducted at the Indian Institute of Horticultural Research, Bangalore, in Rabi season during 2001-2002 and 2002-2003 to study the flowering of Cytoplasmic Male Sterile Lines CMS (A) and pollinator lines (C) of onion cv. Arka Lalima for working out effective synchrony in hybrid seed production. Results indicated that days to 100% flowering and days to complete flowering in a plant varied significantly in the parental lines and C line was found to be earlier than A line by 12 days and 25 days, respectively. The duration of flowering in a plant was also less in C line (23 days) than in A line (29 days). Due to lack of floral synchrony between parental lines, pollen availability becomes a limiting factor in hybrid seed production in cv. Arka Lalima. Delay in planting of C lines by a week after planting A lines resulted in synchronised flowering of parental lines at peak flowering stage. This also resulted in higher fruit set (80%) and hybrid seed yield (15g/plant) as against planting of A and C lines simultaneously (29.54% and 0.38g, respectively).