84 



The Journal of Heredity 



parent and four wheat varieties Forty- 

 fold, Jenkin, Jones Fife and Hybrid 128 

 as male parents. Table 1 gives the 

 performance data for all four of these 

 hybrids for the years 1919, 1920, and 

 1921. 



A comparatively high percentage of 

 the flowers treated set seed but very 

 few of these produced Fi plants. The 

 five seeds of Rosen X Fortyfold re- 

 sembled rye in general appearance but 

 were badly shrunken and all failed to 

 produce Fi plants. The taxonomic 

 characters of the Fi plant of Rosen X 

 Jenkin were very much like those of 

 rye but were slightly modified by the 

 wheat parent. It was evident from 

 these modified characters and from the 

 95 percent sterility displayed that this 

 was a true Fi plant. The same might 

 be said of the appearance of the Fi plant 

 secured from Rosen X Jones Fife but 

 this was slightly more fertile. Four Fi 

 plants of Rosen X Hybrid 128 were also 

 secured. These again did not differ 

 greatly from rye in their botanical 

 characters but they all exhibited a 

 high degree of sterility which varied 

 with the individual from 75 percent for 

 the most fertile one to 90 percent for 

 the one highest in sterility. 



Table 2. Distribution of the differing characteristics of the parent plants and their F-i hybrids in 



the rye-wheat crosses 



SECOND GENERATION OF RYE-WHEAT 

 HYBRIDS 



The character which showed the 

 greatest variation in the F2 was the 

 degree of fertility. This ranged from 

 complete sterility to complete fertility 

 with an average of 50 percent. The 

 average fertility is much greater than 

 that shown in the Fi generation, as the 

 Fi plants were all in class 1. (See below. ) 



The data on fertility are shown in 

 table 2 which gives the distribution of 

 the differing characteristics of the 

 parent plants and their F2 hybrids. 

 The method of obtaining the data was 

 as follows: the plants were pulled and 

 brought into the laboratory where an 

 estimate of the fertility was made by 

 passing the heads of each plant through 

 the fingers. After a little practice one 

 can readily tell whether the floral 

 glume contains a seed or is sterile. The 

 plants were arbitrarily thrown into 

 five classes. Class 4 represents as 

 complete fertility as is normally found 

 in wheat, class represents complete 

 sterility and classes 1, 2 and 3 repre- 

 sent degrees of fertility approaching 

 one-fourth, one-half and three-fourths 

 respectively. With the exception of the 

 wide variation in fertility the F2 plants 



1940 



526 



371 



592 



3905 



3915 



3911 



3912 



3913 



3914 



Rosen rye 



Jenkin 



Jones Fife 



Hybrid 128 



Rosen X Jenkin 



Rosen Xjones Fife.. 

 Rosen X Hybrid 128 



Fertility (a) 



No. plants in each class 

 12 3 4 



12 

 All 

 All 

 All 



(a) The degree of fertility was arbitrarily divided into five classes, class 4 represents as com- 

 plete fertility as is normally found in wheat, class represents complete sterility, and classes 1, 2 

 and 3 represent a degree of fertility approaching one-fourth, one-half and three-fourths. 



(b) 3 year average. 



(c) 10 year average. 



(d) No record. 



