Seasonal Variation Affecting Sex Expression of Coba (Zizania latifolia Turcz.)

Abstract

Coba (Zizania latifolia Turcz.) cv. Green Shell flowers continuously from early May to mid-November in southern Taiwan. It is m000ecious, which male and female flowers occur on the same infiorescence. Each inflorescence consists of many spikelets and forms a large panicle. Most of male flowers distributed at the lower portion of spikelets in the inflorescence, while the female flowers distributed oppositively. The length of inflorcscence, inflorescence node, and lateral inflorescence; no. of lateral inflorescences, total flowers, deformed flowers, male Cowers vary with the flowering month. The length of flower infiorescence, inflorescence node and lateral inflorescence do not vary from May to September, but decrease after October. The no. of lateral inflorecence, total flowers, deformed flowers, male flowers and female flowers increase from May, reach a maximum in August or September, and then decrease. The ratio of male/female flowers is highest (at 4 :1) in May and then gradually decreases to 2 : 1 in July and August, to 1 : 1 in October, and then sharply decreases in November with veryfew (if any) male flowers.