The Paraná State (Brazil) significantly contributes to the supply of onions in Brazil. However, the seed yield activity is far below that desired, giving rise to a need for research in this area. This experiment was conducted in Ponta Grossa county to evaluate the effect of vernalization periods on different sized bulbs on seed yield and physiological potential of onion seeds, cv. Crioula. The experimental design was of randomized blocks with four replications; the treatments followed a factorial scheme 4x2, with four vernalization periods at 5(0)C (control, 25; 35 and 45 days) and two sizes of bulbs (T1 with 6,9 cm of diameter) and T2 (4,8 cm).The vernalization contributed to an increase of seed yield. The longer the treatment period, the higher the percentage of umbels, number of seed stalks, total number of capsules and capsules with seeds. These components contributed to higher seed yield per umbel, both in number and weight, the periods of 35 and 45 days being the most favorable. However, on the seed yield per plant, the period of 45 days prevailed. The seed physiological potential was not affected by the treatment. Germination was higher than 80,0% on the first test counting and higher than 90,0% in the last count, independent of treatment. Bigger bulbs (T1) produced greater number of flower stalks and larger amounts of fertilized flowers. These two parameters contributed to a higher seed yield per plant when compared to T2.
Allium cepa L.; bulbs frigorification; seed yield
