A GOLDEN VARIETY OF RYE 



Juan Williamson 

 Estacion Agroiiomica, Giiatrache, F. C. Pac, Pampa Central, Argentina 



IX THE winter of 1914, while walk- 

 ing over a neglected field that had 

 been sown with rye the i^rcvious 

 year, I noticed many volunteer 

 plants of this cereal, amongst them one 

 with a distinct yellow foliage. I was 

 curious to know if the plant was healthy 

 or if the yellowness was due to some 

 disease, so carefully lifted the plant 

 and, after dividing it into three, had 

 them planted on a small plat among 

 some wheat experiments where they 

 would be taken care of. 



Owing to the fact that rye is almost 

 entirely self-sterile it was necessary to 

 grow a few normal plants by the side 

 of this yellow one to insure the setting 

 of some seed. With the idea of getting, 

 by chance, one or two self-fertilized 

 seeds, five ears were bagged in the usual 

 way, but not a single seed was formed. 

 The other ears, that were left to nature, 

 set almost 100% of their flowers. This 

 seed was harvested and sown the follow- 

 ing year, 19LS, on a i)lat 3 meters 

 square, and as was expected practically 

 all the resulting plants were nonnal 

 green. One, however, was yellow like the 

 mother plant, evidently self-fertilized. 

 All the ears of this yellow plant were 

 bagged and the result was the same as 

 the first year, no seed being formed. 

 The normal green plants gave a fair 

 amount of seed which was sown the 

 following season on a 10 by 10 meter 

 plat. Again, as was expected, this seed 

 produced green plants and yellow plants 

 in the proportion of three of the fomier 

 to one of the latter. All the yellow 

 Ijlants were dug out and planted on a 

 small plat by themselves, and the green 

 ones were destroyed before flowering 

 time to prevent the ]X)llen of green 



plants from fertilizing the flowers of 

 the isolated yellow plants. 



Unfortunately the locusts came while 

 the plants were still young and tender, 

 and destroyed the greater part of them, 

 the result being that very little seed 

 was obtained. 



However, this amount of seed is quite 

 enough to demonstrate that the yellow- 

 ness of the plants is a true recessive 

 character, and that when yellow plants 

 are grown together a good distance from 

 any green plants, and their seed har- 

 vested and sown, their progeny are all 

 yellow, as is proved by our 1917 plat. 



Now arises the question: How does 

 the yellow plant lose its greenness'" Is 

 it due to susceptibilit}^ to some bac- 

 terial disease brought about by the 

 dropping out of a factor the presence 

 of which makes the plant ordinarily 

 immune, or is it simply a case com- 

 parable with the "dilute" forms of hair 

 color in animals, as, for example, the 

 "blue" of the cat where the black 

 pigment granules, scattered in the hairs, 

 are so spaced out as to give the ojjtical 

 eff^ect of "blueness." Here, the chloro- 

 phyll plastids are presumably so spaced 

 out in the tissues of the plant that the 

 optical effect is yellowness. 



A microscopical examination has not 

 been made to disprove the first theory, 

 but, until the contrary is proved, it 

 seems permissible to believe that it is a 

 case of "dilution." 



Apart from being of scientific in- 

 terest this yellow race of rye ma>' prove 

 to be of i:)ractical value as a garden 

 plant. Being quite hardy, its bright 

 yellow color would give a striking effect 

 in the flower garden during the winter 

 months, and more especially in the 

 early spring. 



568 



