Growth Pattern of Tall and Short Lines of Rice and their Response to Gibberellin

The growth pattern of two types of dwarfness in rice was studied. The difference in height of the tall and short Peta plants was apparent even at the seedling stage. In the dwarf and in the normal Century Patna 231 the difference in height was apparent only after panicle initiation. The four lines had the same number of elongated internodes, with the taller lines having longer internodes. The application of gibberellin resulted in increased plant height, longer internodes, blades and leaf sheaths, and decreased tiller number. Century Patna 231-dwarf showed the least, and short Peta the greatest, response to gibberellin application.