CLASSIFICATION AND INHERITANCE OF SMALL GRAINS 95 



and in F 2 the articulated basal types could easily be determined. 

 These occurred in a close approximation of the ratio of 1 articu- 

 lated base to 3 of the intermediate and saliva types (Fraser, 

 1919). 



Open versus Side Panicle. Nilsson (1901) has used panicle 

 types and seed colors as a chief means of classification. The 

 distinction between the side and the open panicle is easily made, 

 but the various transitional open panicled forms are not easily 

 used in differentiation. Nilsson-Ehle (1908) has explained 

 crosses between an open-panicled and a side-panicled variety on 

 the basis of two main factor differences. Either factor when 

 homozygous or heterozygous produces open panicles. When 

 both factors are homozygous a variety with an open panicle and 

 drooping branches is obtained. When the factors are absent a 

 side panicle results. From crossing two open-panicled forms, 

 9-side forms were obtained out of a total of 112 plants. These 

 side-panicled plants bred true while of the 103 open-panicled 

 plants, 24 again segregated giving both open- and side-panicled 

 forms. The parental varieties have panicles with erect branches 

 while a part of the open-panicled segregates have drooping 

 branches. 



Resistance to Rust. Parker (1918) studied varietal resistance 

 of oats to stem rust, Puccinia graminis avence Erikss. and Henn. 

 and to crown rust, Puccinia lolii avence McAlpine. Crown rust 

 is a serious disease in the South while stem rust is more common 

 in the North. Several varieties of the red oat group of A. 

 sterilis including Burt, proved resistant to crown rust, while 

 certain side oat strains of A. saliva orienlalis belonging to the 

 White Russian group proved resistant to stem rust. 



Studies, of the inheritance of resistance to crown rust under 

 greenhouse conditions, of crosses of Burt with Sixty Day, A. 

 saliva, showed segregation in F 2 . Susceptible and resistant 

 plants, as well as various intermediates, were obtained (Parker, 

 1920). 



A study of the inheritance of resistance to stem rust has 

 been made at the Minnesota Station (Garber, 1921). FI, F 2 , 

 and F 3 crosses of resistant White Russian with two susceptible 

 varieties of A. saliva, Victory and Minota, have been grown. 

 The preliminary results show that for these crosses resistance is a 

 dominant character, the ratio in F z of resistant and susceptible 

 plants approximating 3:1. Susceptible F 2 plants bred true to 



