1920] FIELD CROPS. 641 



wheat Is treated at length, and descriptions of the Red Bobs and Kitchener 

 varieties, together with notes on the wild wheats of Palestine, are included. 



Wheat investigations. — I, Pure lines, .T. Zinn (Maine Sta. Bui. 285 {1920), 

 pp. 48, p/«. 5, figs. 12). — An account of the origin and development of a number 

 of pure lines of wheat by the method of selection is presented. The relation 

 (»f environment to the chemical composition and quality of wheat is discussed, 

 and the soils, climate, and characteristics of the wheals of Aroostook County are 

 described. The author also makes observations on the adaptation of pure strains 

 from Minnesota to the environment of northern Maine. 



Several hundred wheat spikes representing the four chief groups of hard 

 spring wheat grown in Aroostook County were planted in 1915, and by 1917 

 selection had reduced this number to 44 pure lines and to 6 lines of the 

 7 Minnesota strains introduced in 1016. A complete chemical analysis of 37 

 lines and baking tests of HI wlu>at lines made in the spring of 1919 led the 

 lireeder to reject all but VI Aroostook lines and 4 ]\Iinnesota lines for the 

 1019 crop. 



Observations on the different tests may be summarized as follows : Under 

 the same environmental conditions pure lines of wheat showed distinct dif- 

 ferences in physical and chemical chai-acteristics and in the bread value 

 of their grain. The average weight of 1,000 kernels of all lines was found 

 to be 35.314 gra., with the weights for individual strains within a variety 

 ranging from 26.541 to 44.789 gni. and deviating in marked degree from the 

 average of their respective parent varieties. It appeared that strains with 

 the highest weight per 1,000 kernels produced the greatest percentf^ge of 

 yellow berries and yielded flour of poor baking quality. Environmental 

 conditions in Aroostook County are believed to have elevated the originally 

 low kernel weight of the Minnesota seed to the level of that of Aroostook 

 strains in a single season. 



Limited yield data indicated that each variety furnished high and low 

 yielding strains, with greater differences in yield between the lines of the 

 same variety than between varieties themselves. 



A comparison of the protein content of the pure lines in 1917 and 1918 

 rev«"aled a tendency for varieties, as well as strains, to retain their relative 

 rank with respect to this quality from year to year. The coefliclent of correla- 

 tion between the protein content of the pure strains in the years noted was 

 found to be 0.381 ± 0.092. The Aroostook-grown Minnesota bread wheats 

 tended to retain their high protein content in this respect, averaging higher 

 than the Aroostook pure lines. Among the durum strains deterioration was 

 very rapid. Speltz Marz and Hedge Row were the highest of the Minnesota 

 introductions in protein content ; after one season's growth in Aroostook, 

 these lines showed the lowest protein percentage of all 99 strains analyzed. 

 The low protein content is said to have been accompanied by a very high 

 percentage of yellow berries. 



I'reston strains contained the highest percentage of gluten, followed by the 

 •Minnesota, Red Fife. Canada Red, Bluestem, and Marquis lines in the order 

 named. With respect to quality of gluten, Red Fife and Bluestem strains 

 were found to be superior to strains of Preston and Marquis. The Minnesota 

 strains, with the exception of durum and Marquis wheat, yielded a strong 

 elastic gluten of good quality. 



Raking tests brought out very marke<l variations in the flour strength of the 

 different pure lines, the volume of bread loaf baked from 340 gm. of flour 

 ranging from 1,518 to 2,221 cc. The bread baked from the flour of a number 

 of strains possessed excellent baking and eating quality. Data from the 



