Heading and seed production of Alopecurus aequalis and Beckmannia syzigachne in wheat fields in northern Kyushu, Japan

Abstract

Heading and seed production characteristics of Alopecurus aequalis and Beckmannia syzigachne were studied in a wheat field in northern Kyushu, Japan. The time of first heading was positively related to late seedling emergence in both species, and this relationship was clearer in A. aequalis than in B. syzigachne. More than 80% plants of both the studied species developed ears. Of the late-emerging A. aequalis, 80% of heading plants produced seeds, whereas in B. syzigachne, all heading plants produced seeds. The maximum ear number was 8 in A. aequalis and 4 in B. syzigachne, and the maximum ear number decreased with late emergence. Seed production showed a similar trend. The maximum number of seeds produced by a plant that emerged after wheat seeding was approximately 3000 in A. aequalis and 1200 in B. syzigachne. Seed numbers decreased by approximately 90% in plants that emerged by late January.