Effect of radiation on the susceptibility of wheat seedlings to leaf rust. (II)

Changes in rust susceptibility due to partial irradiation of wheat seedlings and its dose dependence

Abstract

The stems and leaves of seedlings of Triticum vulgare (Norin No. 16) were irradiated at second leaf stage by X-rays at 5kγ. The seedlings were inoculated 10 days after irradiation by spraying with an aqueous uredospore suspension of Puccinia triticina. The first leaves of the seedlings were removed 10 days after inoculation and the size of uredosori was measured. The size of uredosori on plants whose whole bodies or stems were irradiated were about 1.7 times larger than that on the control and the plants whose leaves only were irradiated.
Seedlings of T. vulgare (Norin No. 50) at second leaf stage were irradiated by gamma-rays at 0.1, 0.25, 0.5, 1, 2.5, 5 and 10kγ. The seedlings were inoculated 6 days after irradiation by spraying with the uredospore suspension. Seedling length was measured 7 days after irradiation, and then the size of the sori was measured 12 days after inoculation. Inhibition of seedling growth increased with the increase of the dosage, but there was no further decrease in the seedling lengths at dosages above 1kγ. Also, the size of the sori increased with the increase of the dosage, but it did not further increase at dosages above 5kγ.