CLASSIFICATION AND INHERITANCE OF SMALL GRAINS 93 



rity at which the grain is harvested or weathering after harvesting 

 may also modify these color characters. 



The color of the lemma of oats has been classified as black, 

 brownish red, gray, yellow, and white. Different varieties, 

 likewise, exhibit different intensities in the development of a 

 particular color. In some crosses between black and white a 

 ratio of 15 blacks to 1 white was obtained in F% (Nilsson-Ehle, 

 1909), while the majority of crosses show 3 :1 ratios (Nilsson-Ehle, 

 1909), (Gaines, 1917). The simplest explanation is that each 

 color character is due to one or more factors, each factor when 

 heterozygous causing partial or complete development of the 

 character. 



Results of crosses show that yellow is dominant over white 

 or partially so. There are, however, two yellow factors each 

 independently inherited. In a cross between Burt, which 

 produces yellowish red seeds, and Sixty Day, which produces 

 yellow seeds, Frazer (1919) obtained a ratio of 48 red, 15 yellow, 

 and 1 white in F?. These results may be explained by supposing 

 Burt to carry two color factors, R for red and Y for yellow, and 

 Sixty Day one factor, Y l for yellow. Apparently .R produces reds 

 either when associated with F or F 1 or when alone. 



Gray is epistatic to yellow (Nilsson-Ehle, 1909) (Surface, 1916) 

 (Love and Craig, 1918c) but hypostatic to black, while black is 

 epistatic to all other colors so far as determined. It has been 

 tested for gray, yellow, and white but not for brownish red. As a 

 rule the intensity of color is not so great when a factor for a par- 

 ticular color is heterozygous as when homozygous. 



The inheritance of a reddish straw color has been shown 

 by Pridham (1916) to behave as a simple Mendelian monohybrid. 



Hulled versus Hull-less. The hull-less condition has been 

 made the basis of one of the species groups, Avena nuda. Numer- 

 ous crosses between hulled and hull-less forms have given like 

 results. All investigators of these crosses have obtained an 

 intermediate condition in FI, with both kinds of grains, hulled 

 and hull-less, borne in the same panicle. Ratios in F* of 1 of 

 each of the hulled and hull-less forms to 2 heterozygotes have 

 been obtained. The hulled and hull-less types breed true while 

 the intermediates again segregate. Love and McRostie (1919) 

 have found considerable variation in the percentage of hulled and 

 hull-less seeds in different panicles of the same cross. Con- 

 sistent correlation was obtained between the percentage of hulled 



