Size of Plat and Number of Replications in Field Experiments with Cotton 1

In varietal and other experiments with cotton, as with farm crops in general, the question of what size plat and the number of replications to be used to obtain reliable and accurate results is of great importance. The nature of the crop and the great amount of labor necessary in obtaining yield data make it desirable to have as small a plat and as few replications as possible. A great deal has been done in determining the size of plats and numbers of replications for small grains, corn, and other crops, but particularly the small grains. For a comprehensive review of this subject the reader is referred to "Breeding Crop Plants," by Hayes and Gather (~).a The writer has found nothing, however, in regard to cotton. The object of the study reported in this paper is to determine the minimum size of plat and number of replications consls~en~ with accuracy for cotton experiments. At the Oklahoma Agricultural Experiment Station previous to the season of i926 experiments with cotton, excepting varietal tests, have been with one-tenth to onefifteenth acre plats replicated once. Varietal tests have been mostly single rows with no replications. In this test, check plats were included every third or fourth row.