160 Clyde E. Leighty 



grams; and the breaking strength, in grams. For plants with more than 

 one culm the diameter and the breaking strength were determined for the 

 principal culm, according to methods described previously. The means 

 for all three of these characters are seen to decrease markedly as the 

 degree of crowding increases. The variability decreases for weight in 

 line 50, and for breaking strength in both lines, with decrease in amount 

 of room allowed to the plants. In line 62, however, the greatest varia- 

 bility in weight of straw occurs in series 102, where crowding is intermediate, 

 but the least variability is again where the greatest degree of crowding 

 exists. In diameter of straw the variability is greatest in both lines 

 where the intermediate degree of crowding exists, but is least where the 

 crowding is greatest. 



Oat plants grown in very crowded positions produce but one culm to 

 a plant, but as more room is given more than one culm are produced by 

 many plants. Tillering ceases in these varieties when the rate of stand 

 is somewhere about forty to forty-five plants to a foot. The develop- 

 ment of the plants in less crowded conditions is greater than in more 

 crowded conditions, as is evidenced by the means for yield, height, length 

 of head, weight, diameter, and breaking strength of straw, number of 

 spikelets per culm, and number of kernels per culm. The kernels also 

 average heaviest when crowding is least, but there is not much difference 

 in weight for conditions of crowding such as exist in series 100, 122, 

 102, and 118. The numbers of kernels produced by the spikelets do 

 not differ greatly for the different rates of seeding; the number produced 

 on the plants growing under medium conditions of crowding, however, is 

 slightly the largest. 



Variability, as indicated by the standard deviation, decreases in both lines 

 with decrease in the mean in yield, number of kernels per culm, number 

 of spikelets per culm, and breaking strength of straw. In both lines the 

 variability for height of plant and diameter of straw is greatest for the 

 medium thick stand. For height the least variability occurs where the 

 most room per plant is allowed, but for diameter of straw the least varia- 

 bility occurs when the crowding is greatest. In line 50, variability 

 increases with crowding for weight of kernels per plant and for number of 

 kernels perspikelet, and decreases for weight of straw and for length of 

 head. In line 62, variability is greatest in the medium thick stand for length 

 of head, weight of kernels, number of kernels per spikelet, and weight of 



