Micromorphic and Molecular Studies of Floral Organs of a Multiple Seeded Rice (Oryza sativa L.)

Jugal is a natural mutant which produces more than one seed in most of its grain. In rice, development of floral organs is directly linked with seed production; thus, to elucidate the underneath mechanism of multiple seeded trait of Jugal, floral organ development was investigated. Microscopic study showed that most of the Jugal flowers bear more than one carpel; the presence of multiple carpels in Jugal flowers was confirmed by scanning electron microscopy (SEM) study. To understand the mechanism of multiple carpels in Jugal flowers, floral meristems of Jugal and IR36 were investigated, and Jugal floral meristem was found enlarged in comparison to IR36. Fourteen floral organ developmental genes of Jugal were sequenced partially, of which seven were sequenced successfully. Six among the successfully sequenced genes found to have variations and of them three genes showed changes in their corresponding amino acid sequences. Three out the seven genes possess unique variations. Expression study showed Jugal flowering genes expressing differently when compared to normal rice IR36.