Hayes and Garber - Cucurbit Breeding

FRUIT BREEDING 279
It will be of interest here to present briefly an instance from
the fruit-breeding work at the Minnesota Station in which
desirable new plum hybrids were obtained when the tender
parent, Burbank (P. triflora) was crossed with Wolf which is a
hardy variety of P. americana mollis. The percentage of hybrids
killed during winter dormancy is taken as a basis for classification.
It will be seen that some of these hybrids, as No. 8
or No. 9, are hardy in the bud like the staminate parent Wolf.
The two which have been named Red Wing and Tonka, are intermediate
in hardiness but of excellent fruit characteristics.
FIG. 66. Tonka, Burbank X Wolf, No. 21. Has high quality and is nearly
as hardy as the hardy variety of Wolf. (Photo loaned by Dorsey.)
TABLE LXXV. SHOWING THE PERCENTAGE OF BUDS KILLED IN AN F\
PROGENY WHEN ONE OP THE PARENTS is HARDY AND THE OTHER TENDER 1
Parent