Analysis on a New Genetic Behavior of Elongated Uppermost Internode in Rice

An eui(elongated uppermost internode) mutant was found from wild type of Luoshami, in which the uppermost internodes contribute to the variation of plant height. The eui mutation also resulted in significant increase in flag leaf and grain length. The crosses from mutant type/wild type, wild type/mutant type, mutant type/Jinhui 10 and mutant type/Jin 1B expressed normal uppermost internodes in F 1, and segregated differently in F 2(ratio of normal to eui was 3∶1 in F 2 between wild and mutant type, and 13∶3 in F 2 between mutant type and Jinhui 10, Jin 1B). Inheritance analysis indicated that the eui character is controlled by not only a major effective gene but also an inhibited gene. Two genetic systems were proposed to explain the hereditary behaviors. One was that the eui character is controlled by a dominant major gene of Eui and the Eui gene is inhibited by a dominant gene I, and the other was the eui character is controlled by a recessive major gene of eui and the eui gene is inhibited by a recessive gene i.