Abstract
Effects of brown midrib(bmr-18)and bloomless(bm) genes on the resistance to sheath blight were investigated in a field inoculation test by using an F_2 population of the cross between "F_6-3A-5"(bmr-18/bmr-18;bm/bm)and "74LH3213"(Bmr-18/Bmr-18;Bm/Bm). The plants in the F_2 population were classified according to their phenotypes:normal(N), brown midrib(bmr-18), bloomless(bm) and brown midrib and bloomless(bmr-18+bm) types. There were no remarkable differences among these types in the height of flag-leaf collar(HF), heading date which may affect the result of resistance to sheath blight in the inoculation test. However, the height of lesion(HL) relative to the height of HF(RLH) in the bm and bmr-18+bm types were significantly shorter than those in the N and bmr-18 types. In addition, there was no significant difference between bmr-18 type and N Type in the HL and RLH data. These results suggest that the bm gene increases the resistance to sheath blight, and that bmr-18 gene have no negative effects on the resistances to sheath blight. Furthermore, varieties which are resistant to sheath blight and also possess higher nutritive values can be developed by using bm and bmr-18 genes.
