738 EXPERIMENT STATION RECORD. 



\\lit'tber they worked with culms or with plants, art', however, comparable, 

 with slight reservation, as far as this factor affects the results. 



"The second division of this study is a bionietrical comparison of varieties 

 of oats. In this study considerable difference is shown in average yield of 

 culm per plant. This is due to the larger kernels produced by certain varieties, 

 since the number of kernels and of spikelets are about the .same for the 

 different varieties. There are varietal differences in the height of culm. The 

 average number of kernels i>er spikelet is greatest in the Sixty Day and 

 .•^malle-st in the Early Champion variety. The proportion of straw to grain 

 differs in the different varieties. Considerable difference is found in the 

 amount of variability of different characters of the varieties. The greatest 

 A-ariability, in all characters but one, is found in the Welcome variety, while 

 each of the others is least variable in one or more characters. The coefficients 

 of correlation are usually fairly close together for the different varieties, but 

 some dift'erences occur that may be due to varietal causes. 



" The third division of this study is a comparison of biometrical constants 

 determined for oat plants grown in hills and in drills. Regarding all char- 

 acters here studied, the means are greater for plants grown in hills than for 

 plants grown in drills. The least difference In the means occurs in the cases 

 of average height of plant and average weight of kernels per plant. There 

 is greater variability in average yield of culm per plant and average weight 

 of straw in plants grown in hills, but much less variability for plants so grown 

 in average height and average weight of kernels. The variability in number 

 of kernels and number of spikelets is slightly greater for the plants grown in 

 hills. Rather large differences occur in the same variety between the co- 

 efficients of correlation determined for the plants grown in the two ways. 

 AYhenever large differences in the coefficients of correlation occur, those for 

 the plants grown in hills are always the smaller in amount. The differences 

 due only to the growing condition may amount to more than any varietal 

 differences observed in this work. The constants, then, obtained by different 

 investigators are comparable only in so far as the conditions of growth are 

 comparable. 



" The fourth division of this study deals with the effect of different degrees 

 of crowding on biometrical constants of oats. Oat plants grown in very 

 crowded conditions produce but one culm to a plant, but, as more room is 

 given, more than one culm are produced by many plants. The development of 

 plants in most characters is greater in less crowded than in more crowded 

 conditions. Variability decreases with increase in crowding for yield, number 

 of kernels, number of spikelets, and breaking strength of straw ; but for height 

 the least variability occurs when crowding is least. In every case when sipiifl- 

 cant differences exist in the correlations between characters in plants grown 

 under different conditions of crowding, there is an increase in correlations 

 produced by more crowded conditions, but there is sometimes a decrease beyond 

 a certain degree of crowding. It has been shown that environmental condi- 

 tions may influence the degree of correlation of certain characters to a marked 

 extent. Such conditions of environment may make of no significance the so- 

 called varietal and other differences obtained by several investigators." 



A bibliography of cited literature is appended. 



Irish potatoes, J. C. C. Price (Alabama Col. 81a. Bill. 183 {1915), pp. 3-16, 

 figs. 2). — This bulletin describes cultural methods that may be used in Alabama, 

 touching upon soil, varieties, fertilizers, culture, insects and diseases, harvest- 

 ing, and shipping and storing, both for the early crop and for the fall crop, 

 and also gives results of fertilizer experiments for the years 1911. 1912, and 

 1913, and of variety tests for these years and 1910. The best yield was ob- 



