A Fourth Genetic Element to Facilitate Hybrid Cereal Production—A Recessive Tall in Rice1

Abstract

A recessive gene in rice (Oryza saliva L.) for elongated uppermost internode (eui), which effectively results in a recessive tall plant type, is described. The gene produces a near‐doubling in length of the uppermost internode, a 12% increase in panicle length, and little or no effect on other internodes or plant characters. It is proposed that this gene would be a useful fourth element which would complement the other three genetic elements∔cytoplasmic male sterility, maintainers, and restorers—generally used in hybrid seed production. The eui gene would be incorporated in pollen fertility restoring parents in hybrid seed production in situations where a semidwarf F1 generation is desired. The tall paternal plant type would be desirable for windblown pollen dispersal onto semidwarf female plants and the resulting hybrid plants would be semidwarf, unlike the usual case of tall hybrids from semidwarf by tall crosses. Additionally, its increased height would permit a co‐mingling of the hybrid parent seed stocks to maximize crossing and would facilitate mechanical removal of the paternal parent before mass harvest of the commercial hybrid seed.