106 BREEDING CROP PLANTS 



SOME RYE STUDIES 



Wild rye, Secale montanum, differs from cultivated rye in its 

 perennial habit. Tschermak (1914) finds that wild and culti- 

 vated forms may be easily crossed, which indicates rather close 

 relationship. 



Rye (see page 40) differs from the other small grains in that 

 it is cross-pollinated. Sterility is often obtained when self- 

 fertilization is attempted. For this reason it is not easy to 

 produce homozygous strains and therefore few inheritance studies 

 have been made. 



Xenia in rye was first discovered by Giltay in 1893. It was 

 later corroborated by Von Rlimker and others (1913, 1914). 

 By continuous selection, strains have been produced which are 

 pure for color differences. According to Von Riimker, selection 

 for seven or eight years was necessary in order to isolate strains 

 which were homozygous for color of seed. He found the color 

 to be located in the aleurone layer just inside the epidermis. 

 There are numerous colors of rye which are roughly analogous to 

 the aleurone colors of corn. The inheritance of these colors has 

 not as yet been intensively studied. Von Riimker has isolated 

 pure races for greenish blue, deep brown, and yellow seed. 

 There are also deep blue, light brown, and striped seed besides 

 other color variations. In crosses between green- and yellow- 

 seeded strains Von Riimker found green dominant and obtained 

 a ratio of 3 green to 1 yellow in F^. 



There are both spring and winter varieties of rye. The spring 

 habit appears to be a dominant character, for Tschermak (1906) 

 obtained a ratio in F 2 of 3 spring forms to 1 winter form. 



Wheat-rye Hybrids. Numerous investigators (Backhouse, 

 1916-1917 ;Leighty, 1915, 1916; Jesenko, 1911, 1913; McFadden, 

 1917) have reported crosses between wheat and rye. In all 

 reported successful crosses, wheat has been used as the female 

 parent. Rye is very winter hardy and as winter wheat is much 

 less hardy it is only natural to try to improve winter wheat by a 

 rye-wheat cross. As a rule the FI cross is self-sterile, although 

 back crosses with the parents have sometimes been successful. 

 Love and Craig (1919 a) have described a successful wheat-rye 

 cross, using Dawson's Golden Chaff as the wheat parent. Stud- 

 ies have been continued through F and F$ and a number of 

 plants have been obtained which exhibit little or no sterility. 



