Abstract
A major factor in the Green Revolution was the extensive use of fertilizers in the cultivation of high-yielding. Under such condition, traditional varieties of rice grow surplus tall and are susceptible to lodging, which breaks their basal culms and results in severe yield loss. In contrast, dwarf varieties respond to high fertilizer inputs and produce more grain because their short stature are resistant to lodging. Previous studies revealed that the dwarf genes contributed to Green Revolution are involved in gibberellin biosynthesis or signaling, and therefore it has been considered that GA deficiency or insensitivity may be good trait for high-yielding. However, direct evidence is lacking. Thus, we studied the effect of GA on culm strength by using different kinds of rice GA-related mutants. The dwarf phenotype enhanced the bending-type lodging resistance. On the other hand, it also causes lower culm strength. Such ambivalent effect of GA on lodging resistance indicates that GA may not be the best target for lodging resistance. This work was supported by a grant from the Ministry of Agriculture, Forestry and Fisheries of Japan (Genomics for Agricultural Innovation, IPG-0003).
