Variation and Correlation of Oats— Part I 65 



since it is sometimes thought that the average yield of culm would tend 

 to decrease as the number of culms on the plant increased. 



Another important fact brought out by this study is the relation between 

 average weight of kernels and height of plant, and average weight of kernels 

 and total yield. This has an important bearing on the practice of seeding 

 oats. 



The question of size of seed is one that has been much discussed. The 

 common advice given to a grower is that he should reclean his seed in 

 order to obtain only the largest and plumpest for sowing. Many experi- 

 ments have been conducted in order to determine the relative value of 

 hght and heavy seed. Among these, and possibly the best known of all 

 such experiments, are those under the direction of Professor C. A. 

 Zavitz, at Guelph. In these experiments Professor Zavitz worked with 

 hand-picked seed, thus being sure to have a good separation of light and 

 heavy grains. The results show a good gain in yield per acre from the 

 heavy seed. Other results with small grains have been obtained at the 

 Ohio Agricultural Experiment Station (Williams and Welton, 1911 and 

 1913), and also at the Nebraska Agricultural Experiment Station (Mont- 

 gomery, 1908). These results do not agree with those found by Professor 

 Zavitz, since no marked results were obtained by sowing larger seed. 

 The difference between the seed used by Professor Zavitz and that sown 

 at the Ohio and Nebraska Stations was that the former was hand-picked 

 and the latter was separated by the use of a fanning mill. 



One of the "WTiters has sown hand-picked seed of a number of varieties 

 of oats, and found that in every case the larger yield was obtained from the 

 heavy seed. In another test with oats, in which large and small kernels 

 from the same head were compared, the large seed gave a greater yield. 



Although there have been many experiments comparing large and small 

 seed, few studies have been made to determine the parentage of the large 

 seed. Do large seeds come from large plants, or do the smaller, low- 

 yielding plants produce a large percentage of heavy seed? Another 

 point along this line that needs consideration is the relative value of small 

 seed from large plants, as compared with large seed from small plants. 



Waldron has made a valuable contribution to the study of light and heavy 

 seed. His data were taken on oats, but he also made some calculations on 

 data taken by Dr. T. L. Lyon and reported in Bulletin 78 of the United 

 States Bureau of Plant Industry. Waldron's paper shows the value of the 



