Introduction of the leaf-rust resistance to wheat
variety from T. Timopheevi
Y. WATANABE, K. MUKADE and M. YAMADA
Morioka Experimental Farm, Tohoku National Agricultural Experiment Station
Morioka, Japan
In 1953, 14 F1 plants were raised from 93 seeds obtained by
pollinating 340 florets of Fultz No. 1 (T. vulgare) with T.
Timopheevi. F1 plants were highly sterile, but 7 B1F1
seeds were obtained from the 352 florets of F1's pollinated
with the pollens of Fultz No. 1, and 6 of them germinated and reached
maturity. It was found that 1 plant showed leaf-rust resistance both in
the seedling stage and in field condition by an artificial inoculation
with race group 21 of Puccinia triticina, which prevailed over
Tohoku districts of Japan most virulently among several race groups. This
plant was fertile, and gave the progeny with high leaf-rust resistance.
Of 149 B1F2 plants, 46 showed high resistance to
the leaf-rust in both seedling and adult stages. The B1F1
population was again subjected to the artificial epidemics in a disease-garden.
Consequently, 11 strains were selected which appeared to be homozygous
for the resistance. The following table shows the somatic chromosome number
and the main meiotic configurations at MI in PMC's of B1F2
and B1F3 plants.
The cytogenetical study was carried out for 10 plants selected at random
in B1F4 generation obtained from FTF-21 with 21II.
Acetocarmine smears of their root-tips showed 42 somatic chromosomes,
and 21II were observed at MI in PMC's, exclusively. Although
these plants in B1F4 generation showed a wide range
in segregation for various morphological characters, no tendency of glume
adherence which is typical of T. Timopheevi was found. Their seed
fertility was considerably high. The time of maturity was a little later
than the common winter wheat varieties, and, contrary to our expectations,
they were attacked severely by the stem-rust epidemics in June, 1957,
which had been very rare in the Tohoku districts.
(Received Sept. 1, 1957)