Morphological, Anatomical and Genetic Analysis for a Rice Mutant with Abnormal Hull

A mutant with abnormal hull was first discovered from a twin-seedling strain W2555 in rice (Oryza sativa L.). The mutant had sparse branches and decreased number of florets from the base to the peak. Frequently, the florets at the top of the panicle did not develop completely. The underdeveloped florets often showed slender and white in their life cycle. Genetic analysis indicated that the mutant traits were controlled by a single recessive gene (temporarily designated as ah). ah gene controlled the development of inflorescence meristem and the flower organ. The florets of mutant showed degenerated lemma and palea. Stamens and lodicules were homeoticly transformed into pistils and palea/lemma-like structures, respectively. It seemed that ah mutant phenotypes of the homeotic conversions in lodicules and stamens were very similar to that of the B loss-of-function spw1 gene reported previously in rice.