Semidwarf Wheats
Speech by Orville Vogel, PNW Historical Society, 1977
The need for drastically shorter and more lodging resistant winter wheats
had become apparent after growers began planting winter wheat early and
applying unusually heavy amounts of nitrogen fertilizers. Often
accompanying the resultant unusually high grain yields was severely
lodged grain. Varieties such as Omar and Brevor, which were considered
to be highly resistant to lodging when released, often became severely
lodged when managed for the new levels of production.
Being aware of our lodging problems, B.B. Bayles sent a collection of
semidwarf wheats for preliminary observations at Pullman in 1949. From
these, Norin 10 was selected to be crossed with Brevor which at that time
Brevor was considered to be the most lodging resistant high yielding
variety with short straw. The history of Norin 10 and its uses are given
by Reitz (4).
The best segregates from this cross were not suitable for commercial use
in Washington, and therefore many of them were crossed with many other
varieties and hybrid segregates. A very large proportion of the new
crosses produced no segregates worthy of further use. One selection,
however, Norin 10 x Brevor, Selection 14 , was
among those showing
encouraging agronomic performances (5,6). Its greatest value, however, was
a parent which contributed not only short, lodging resistant straw, but a
greatly increased yield capability to breeding programs throughout the
world.
Norin 10 appeared to be susceptible to every important plant disease in
the PNW. In addition, a very high proportion of segregates from crosses
with it were partially male-sterile. Also, nearly all of the best
appearing segregates had a brittle rachis which would cause the heads to
"snap off" from the stems when ripe and before they could be harvested.
Consequently, any successful breeding for commercially acceptable
semidwarfs required painstaking efforts and good luck in selecting and
mating parents.
The first semidwarf winter wheat suitable for commercial production was
Gaines, a soft white developed in Washington and released in 1961. It
soon became the dominant variety with yields above 100 bushels being
common under both dryland farming and irrigation. Its high resistance to
lodging, shattering and all prevalent races of bunt encouraged (1) a
widespread planting under irragation, (2) earlier planting in the fall
for better control of soil erosion, and (3) greatly increased use of
commercial fertilizers. However, it created new problems and intensified
others.
The most baffling of the new problems is a combination of after-ripening
dormancy of the seed, and short coleoptiles of the seedlings which caused
difficulties in obtaining satisfactory stands of wheat in early fall
planting. When planted sufficiently deep to be placed in moist soil the
short coleoptile could not reach the soil surface and the seed leaf
would wander under the soil surface and eventually die. Those eventually
reaching the surface often were very weak, thereby resulting in reduced
yields and unusually poor competition with weeds. Intensive efforts to
develop new semidwarfs having a notably longer coleoptile and less
after-ripening dormancy have resulted in a painfully slow development of
at least some of the needed improvements.
Some of the milling industry voiced strong disapproval of Gaines, because
it did not mill any easier than Brevor. Consequently, a sister selection
of Gaines, named Nugaines, was released in 1965 because it milled notably
faster and was more resistant to stripe rust. After its approval for
release, we breeders were informed that the milling industry had adopted
measures to permit milling of wheats comparable with Gaines and that they
were resigned to accepting similar wheats. Nugaines largely replaced
Gaines, primarily because it was the less severely injured by stripe
rust.
With the widespread adoption of early planting came the need for new
varieties more resistant to stripe rust, Cercosporella foot rot and
lodging. Fortunately, the breeders have used a wide range of sources of
resistance to stripe rust and have developed new resistant varieties.
However, the appearance of new races have already outdated some new
releases and late generation selections. For example, Moro, developed in
Oregon, and Paha, developed in Washington, already have become victims of
new races.
Breeding of semidwarfs resistant to Cercosporella foot rot has been very
discouraging. The best progress in Washington, to date, is represented by
a selection named Cerco. It has soft red grain, and therefore is useful
only as a parent for additional breeding.
Recently, two soft white semidwarf varieties developed in Oregon, namely
Hyslop and McDermid, have become commercially important in areas not yet
containing the new races of dwarf bunt. Other new semidwarfs developed
in Oregon and Washington are expected to become commercially important in
the near future.
New and modified objectives facing breeders are the result of anticipated
soil erosion regulations from the Environmental Protection Agency. These
objectives are for the development of new varieties much better adapted
to very early planting to control erosion on summerfallowed land, and for
new varieties better adapted to minimum or no-till systems of wheat
production. For the latter conditions a renewal of efforts to develop
facultative varieties will be warranted.
1. Brumfield, Kirby. 1968. This was wheat farming. Superior
Publishing Co., Seattle, WA.
2. Holmes, E.S., Jr. 1901. Wheat growing and general agricultural
conditions in the Pacific Coast region of the United States. USDA Misc.
Bul. 20.
3. Clark, J.A., and B.B. Bayles. 1935. Classification of wheat
varieties grown in the United States, USDA Tech. Bul. 459.
4. Reitz, L.P. 1968. Origin, history, and use of Norin 10 wheat. Crop
Sci. 8:686-689.
5. Vogel, O.A., J.C. Craddock, Jr., C.E. Muir, E.H. Everson, and C.R.
Rohde. 1956. Semidwarf growth habit in winter wheat improvement for the
Pacific Northwest. Agron. J. 48:76-78.
6. Vogel, O.A., R.E. Allan, and C.J. Peterson. 1963. Plant and
performance characteristics of semidwarf winter wheats producing most
efficiently in eastern Washington. Agron. J. 55:397-398.