Production of Cabbage Seed in the Subtropical Lowlands

News source: Tainan District Agricultural Improvement Station, Taiwan
For further information: Research Bulletin of Tainan District Agricultural Improvement Station 37:56-64, 2000</I>, 2001-01-01

Low Temperatures Needed to Induce Flowering

Seed production of common cabbage in the tropics and/or subtropics is hindered by a lack of low temperatures. Winter temperatures in the lowlands cannot meet the chilling requirement for flower induction. Even if plants can be vernalized at high altitudes, flowering and seed development will be poor, because of high humidity and high temperatures in the following rainy season. We developed a seedling vernalization method to overcome the chilling requirements, so that cabbage seed could be produced in lowland tropics over the winter season.

Vernalization of Young Cabbage Plants

Four cultivars of cabbage, i.e. K-Y cross, Sha-Phon, Summer Summit and Yensen, were sown in plug trays. The seedlings were transplanted into 3.5-inch pots at 45, 55 and 55 days after sowing. The plants were then vernalized at 5^oC for 45 days with 16 hr/day of illumination (1,000 lux). Vernalized plants were planted out in the field on November 24, 1998, and seeds were harvested on March 10, 1999. The results show that the seedling age and cultivar significantly interacted in determining the seed yield. In the variety "Yensen", seed yield decreased with an increase in seedling age at vernalization. The highest seed yield in the "K-Y cross" and "Summer Summit" were found at a seedling age of 55 days. The 45-day-old plants of "Sha-Phon" produced the highest seed yield. Among the combined treatments, highest seed yield in the variety "Yensen" was found when 45-day-old plants were vernanized for 45 days. They produced 71.5 g seeds/plant. The lowest seed yield was the variety "Summer Summit", when 45-day-old plants were vernanized for 45 days. They produced only 48.7 g seeds/plant. This experiment indicates that cabbage seed production in the subtropic lowland is feasible if seedlings are vernalized.

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