ISHS Acta Horticulturae 53: IV Africa Symposium on Horticultural Crops
PREMATURE BOLTING OF ONION (ALLIUM CEPA L.) IN THE ARID TROPICS OF THE SUDAN |
| Authors: | A. A. Abdalla, Gaafar M. El Hassan |
| Abstract:
In the arid tropics of the Sudan, the common onion (Allium cepa L.) is grown as an irrigated early and late winter crop. The early crop is sown in August-September, transplanted 6–8 weeks later and harvested during January-March. The late crop is transplanted during November-January and harvested in May-July. Part of the late crop is usually stored. A high percentage of premature bolters is observed in the bulb crop of the local Sudanese red-skin open-pollinated type grown from seed or from transplants. Randomized block field experiments were conducted over 3 years to study the effect of sowing dates spread over the period August-February at monthly intervals. The crop was direct-sown on both sides of ridges and later thinned. The bolting percentage was highest from the early sowings (70–80%) and decreased markedly with later sowing dates (10%). In the early planting about 40–50% of the bolting plants produced single seed-stalks and about 20–50% produced more than one seed-stalk. Splitting decreased with delay in the sowing date. Percent split bulbs ranged between 35 in the early plantings and 10 in the late plantings. Non-bolting and non-splitting bulbs are being selected for bolting resistance. | |
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