Ecological studies on Chinese cabbage. II. Relationship between the difference in sowing time and the appearance of the principal characteristics of Chinese cabbage sown in the autumn, and the effects on Chinese cabbage of various lengths of time of submergence.
Nakagawa, H.; Kamimura, S.; Sato, I.
Bull, Tohoku nat. agric. Exp. Stat, 15, 81-7
Early varieties sown on 9 August showed flower bud differentiation 13 days after the air temperature dropped to 15 degrees C. or below, whereas in late varieties flower buds differentiated 43 days after the temperature dropped below 15 degrees C. The optimum temperature for the cultivation of Chinese cabbage was 18.7-19.2 degrees C. Submergence for 6-12 hours had little or no effect on young plants, but growth was checked after 24 hours' submergence.