Hayes and Garber - Cucurbit Breeding

CLASSIFICATION AND INHERITANCE IN WHEAT 87
disease causes an annual decrease of 15 per cent, in the yield of
winter wheat in the States of Washington, Oregon, and Idaho.
The method used in studying bunt resistance was to blacken
the seed with smut spores just before planting and then sow the
strains and crosses in rows in such a way that each plant could
be individually examined.
Studies of inheritance were made in crosses of Turkey X Florence
and Turkey X Hybrid 128. Hybrid 128 is a prolific,
winter-hardy, stiff-strawed wheat of much commercial value
but it is
very susceptible to bunt. Turkey does not yield as well
as Hybrid 128, has weak straw, and shatters considerably. It is
highly resistant to bunt. Florence is an Australian spring wheat
which is highly resistant to bunt.
The results presented b}^ Gaines show very clearly that resistance
to bunt is an inherited character.
However, several factors
are necessary to explain the sort of segregation obtained. The F 2
of the cross between Florence and Turkey showed transgressive
segregation. In Fa, 171 families were grown from individual F 2
plants. Of these, 72 were immune while 50 families produced over
80 per cent, of bunt. The Turkey and Florence parents under
the same conditions produced an average of 4.6 per cent, of
infected plants. This shows that the factors for resistance in the
Florence and Turkey varieties are not identical.
In the cross between Turkey and Hybrid 128 no segregates
were obtained with a higher degree of resistance than the Turkey
parent. It was found possible to produce resistant strains of
any morphological type desired.
Inheritance of Other Characters. Nilsson-Ehle (IQllc, 1912)
has shown that winter-hardiness is inherited in much the same
manner as other characters. Segregation occurs in F% and types
can be produced in later generations which are homozygous for
different degrees of winter-hardiness. Crosses made (Hayes and
Garber, 1919) in 1902 between hardy Odessa winter wheat and
Turkey varieties were bred for several years by continuous selection
methods. Odessa is a late maturing variety and does not
give a high yield in Minnesota. Turkey is a desirable winter
wheat in many sections but it lacks hardiness under Minnesota
conditions. Two early maturing wheats, Minhardi and Minturki,
have been produced from the cross between Turkey and
Odessa. These new varieties excel in winter-hardiness and
yield.