关键词: 水稻, 小穗梗弯曲, 突变体, 形态特征, 基因定位

Abstract: Rice pedicels are tightly associated with the yield of grain. In the present study, a novel and stable pedicel mutant bpb1 (bent pedicel branch 1) was obtained from the wild type “Zhenong 7” after ⁶⁰Co γ-ray treatment. The mutant had the typical phenotype of bent pedicel branches with multiple abnormal phenotypes, such as longer pedicels, short panicles, and dwarfism. Detail examination using scanning electron microscopy revealed that the pedicel epidermal hairs and stomas in the mutant were smaller than those in the wild type. The epidermal and sclerenchymatous cells were arranged irregularly, and the cells in the bend region of pedicels became smaller and arranged closely. The transverse observation of the mutant pedicel branches showed that the small vascular bundles arranged differently from those of the wild type. Genetic analysis indicated that the abnormal phenotypes were controlled by a single recessive gene. Using the F₂ mapping population from the bpb1 mutant crossed with the japonica rice variety “Zhenongda 104”, the bpb1 gene was mapped in a 343 kb region between two SSR markers, RM21537 and RM21552, at the long arm of chromosome 7. Because no homologous gene was found in this re-gion until now, bpb1 might be a novel gene related to the pedicel development and growth. This study could be beneficial to future cloning and functional analysis of the bpb1 gene.

Key words: rice, bent pedicel branchs, mutant, morphological characteristics, gene mapping