832 EXPERIMENT STATION RECORD. 



of oats represent 3 complete and independent nnit characters. New color forms 

 appearing in the crosses as observed in this breeding work were fonnd to be 

 new combinations of groupings of unit characters of the parents. The author 

 states that in none of his crosses did he observe unit characters which were 

 not present in the parents. 



Work with wheat was conducted with varieties having brown and light 

 colored heads. Tlie crosses of spring wheat varieties in the F3 generation 

 showed upon the one hand the ordinary Meudelian segregation, the exceptions 

 being apparent rather than real, and on the other hand that in such mono- 

 hybrid segregations different transmissible gradations of the brown color are 

 formed. Of 7 ci'osses of spring wheats with brown colored heads only one 

 gave evidence of dihybrid segregation or of the presence of 2 unit characters 

 with reference to the brown color, but these were not discernible from external 

 appearance. In crosses between deep brown and white-headed forms the color 

 of heterozygotes was always plainly brown even if reduced, and the mouohybrid 

 segregation was in the proportion of 3 brown-headed individuals to 1 of the 

 white-headed. Crosses between light brown and white forms showed little or 

 no brown color in the heterozygotes. 



The color of the grain was studied in 5 crosses between red and white- 

 grained varieties of wheat. Two of the crosses plainly segregated in the pro- 

 portion of 3 : 1, and one, a cross between a white-grained variety and Swedish 

 velvet wheat (a red-grained sort), showed a constantly red-grained strain in 

 the second generation. These and other results in this experiment were taken 

 as indicating with considerable certainty that the red color of the kernel in 

 Swedish velvet wheat includes 3 independent unit characters, each one by itself 

 capable of producing the red color in the grain. The author maintains that 

 the differences outwardly apparent in the effect of these various units are so 

 small that quantitatively they may be considered as practically equal, and he 

 points out that the units clearly mendelize in the same manner. Germination 

 experiments indicated tliat the pigment in the seed coat of the wheat kernel 

 seems to retard germination when exposed to the air under conditions of tem- 

 perature and moisture favoring growth. 



In another series of breeding experiments a variety of yellow-glumed side 

 oats, Jaune Geant a Grappes, which is one of the few varieties having no 

 ligules, was crossed with several varieties provided with ligules. The results 

 showed a definite connection between the presence of ligules and the type of 

 panicle. In all cases the progeny in which the absence of ligules was constant 

 was of the side-oat type, while the progeny in which ligules were present was 

 of the spreading panicle type. It was further shown by experiment that the 

 ligule character of one of the varieties was determined by 2 units segregating 

 independently of each other. One of these determined the spreading type of 

 panicle, the other a rather loose form of the side-oat type, while the absence 

 of both units determined the compact form of side-oat head, together with the 

 absence of ligules. In view of the results secured, the spreading panicle type 

 is regarded as the more complicated form, brought about by the presence of 

 unit characters more or less numerous and influencing the position of the 

 spikelet stems. The segregation observed in the F- generation Indicated the 

 presence of 3 unit ligule characters in 2 varieties, and of 4 in 1 variety. 



Eight crosses were made between spreading panicle and side-oat varieties to 

 study the influence of the type of panicle as a character. It was found that 

 2 varieties had each a special unit determining the character of spreading 

 panicle. In crossing these 2 varieties it is pointed out that since the presence 

 and the absence of each unit constitutes a character pair, forms must arise in 

 which both units are absent and this determines the side-oat type of panicle. 



