| dc.description.abstract | In Kenya onion seeds are very expensive because they are all
imported due to lack of low temperatures for vernalization
requirements. A study was conducted in 1992 and 1993 at Kabete to
determine the effect of bulb size, vernalization temperature and
duration on onion seed yield. It also aimed at comparing artificial
and natural vernalization on onion seed production. Three
introduced onion cul tivars namely KON2, KON4, KON6 and locally
popular Tropicana Hybrid were grown at Kabete for bulb production.
Bulbs of three sizes (40, 55 and 80 mm diameter) were vernalized
naturally at Njambini (2530 m above sea level) and artificially at
10° in an incubator. The non vernalized bulbs were stored at Kabete
at room temperature (17-18°C). The mother bulbs were vernalized for
1, 2, 3 and 4 months and grown at Kabete for two seasons. The
experimental design was a split-split- split plot with three
replicates. Results indicated that vernalization temperatures,
duration and bulb size significantly influenced seed yield of all
cultivars. Flower stalk length, number of leaves per plant, days to
flowering and seed maturity were inversely related to duration of
vernalization. One thousand-seed weight and germination percentage
increased with increasing vernalization duration. Percent
flowering, number of flower stalks per mother bulb, number of
florets per umbel and seed yield significantly increased with
storage duration to an optimum of two and half months.
Vernalization of mother bulbs significantly reduced the number of
leaves per plant, days to flowering, seed maturity and flower stalk
length but significantly increased percentage of flowering shoots,
number of seed stalks per plant, the number of florets per umbel,
1000-seed weight, seed yield and germination percentage. An
increase in bulb size significantly increased the percentage of
flowering, number of seed stalks per plant, number of florets per
umbel, flower stalk length, number of leaves per plant and seed
yield but had no significant effect on days to flowering and seed
maturity, 1000-seed weight and germination percentage. The optimal
storage duration and bulb size for seed production were 2~ months
and large bulb size (80 mm diameter), respectively. Natural
vernalization was as effective as artificial vernalization and
therefore, can be utilized for commercial onion seed production | en |
