The industrial quality of hard wheats depends upon their milling quality and the value of the flour for bread making purposes. The efficiency of the grading system would be greater and the market evaluation of wheat simplified if certain physical properties (kernel color, texture, vitreousness, test weight) and protein content of all varieties within a wheat class uniformly reflected their intrinsic value, but unfortunately this is not always true. For good milling quality, the kernels should be plump, uniformly large in size to permit ready separation of foreign material, absorb water readily and uniformly in the tempering process, and produce a high yield of flour of low yellow pigment and ash content with a maximum and clean separation from the bran and germ without undue consumption of power. Milling characteristics cannot be determined with any degree of precision on small batch-type experimental mills. Baking quality is defined as the sum of excellence on several points and includes the production of satisfactory bread over a considerable range of baking conditions, the facility with which large masses of dough can be handled in the bakery, and the bread yield obtainable, whereas baking strength refers to inherent capabilities of the material as measured by loaf volume under optimum conditions. In general, strong flours yield "tough" doughs requiring more mixing and fermentation and having greater tolerance to variations in these factors than weaker flours, but the parallel between loaf volume-producing ability, dough handling properties, and processing requirements does not hold for certain varieties. Baking quality is determined by using different formulas and procedures which, under ideal conditions, are so designed as not only to reveal the inherent strength of the sample but also to secure a measure of the baking conditions, such as extent of mixing, length of fermentation and oxidation requirements, and the range of each of these which affect the production of the optimum loaf. Handling properties of the dough are of particular importance in relation to the value for blending with weak wheats. The variety should yield a flour which is "well balanced" in regard to the various attributes of quality. Commercial testing of new varieties is advisable and the cooperation of the miller and mill chemist is essential to give workers in wheat breeding stations a knowledge of the requirements of the trade and to uncover points of quality which may have been overlooked or are not readily ascertainable from purely laboratory tests. Where the present types of wheat are satisfactory in quality, the plant breeder should endeavor to produce wheat with the desired agronomic characteristics, resistance to insects, diseases, etc., which are as similar as possible in grading, milling, and baking characteristics to the superior present varieties. New varieties with different processing requirements make it difficult for the miller to deal with mixtures and produce flour of uniform and desired characteristics. In the interests of uniformity, a new variety should not be released for distribution unless it is superior to the present varieties in one or more agronomic characters or disease resistance and is satisfactory in all other respects. The objectives in breeding hard wheat for quality depend on quality requirements of the market and scientific and technological advances may change these requirements or introduce new factors and close contact with the milling and baking industry is essential. Current developments related to increasing the nutritional value of flour may change materially flour quality requirements and lead to a demand for the breeding of wheats of high vitamin content.

The study throws some light on the advisability of using composite samples for the evaluation of new strains or varieties. By compositing grain from several locations, the power to measure differences between locations is lost, and the effect of location on anything being studied cannot be estimated. The question then resolves itself to whether or not these effects can be disregarded without leading to unjustified conclusions. By considering the 4-year combined analysis, it is seen that the variety-location interaction, which gives a measure of the differential response of varieties to locations, is in no case of either considerable size or great mathematical significance. The greatest effect was on yield, which is obtained by locations in any case. This study indicates that serious errors would not be introduced by using composites to rank varieties for weight per bushel, wheat ash, or wheat protein, at least if samples were not drawn from a more diverse set of environmental growing conditions. It must be remembered, however, that the varieties included in this series were all of relatively good quality and of proved adaptability to a much larger area than that covered in this study. From the point of view of the plant breeder or cereal chemist, it seems justifiable to conclude that when strains are tested for several-seasons over a range of soil types representative of the area where a new variety is to be recommended, differences in yielding capacity, weight per bushel, wheat ash, and wheat protein can be measured. The differences need not be very large to be significant. In spite of a considerable variety-season interaction for yield, superior sorts should be distinguished without too much difficulty. In the present study, 4-year averages were clearly significant in spite of marked change in rank between seasons. The standard deviations for a single plot, calculated from the triple interaction, were 3.32 bushels per acre, 0.70 pound per bushel, 0.056% ash, and 0.41% protein. The grower can feel assured that when new varieties are released after several years of intensive testing at representative points in the area considered, their properties have been determined with considerable accuracy and the chances are slight that an undesirable sort will be recommended. The length of time necessary to reach a conclusion will be greater if some seasons vary considerably from normal. This statement assumes, of course, study of more than purely agronomic characteristics.