Mar. 8, 1924 
Diploid and Polyploid Forms in Raspberries 
747 
group of polyploid forms. This pioneer investigation shows that the 
chances of obtaining new combinations have increased with an increase 
in chromosome number and it has been found by studying large popu¬ 
lations from such hybrids that the offspring follow certain genetic laws 
of segregation. It is only by means of such experimental hybridization 
that the plant breeder, who is working with a genus such as Rubus, may 
help to deduce laws of inheritance that will aid him to combine desirable 
qualities from the varied material at hand and segregate them in the later 
generations. 
SUMMARY 
Diploid species and hybrids are the rule in the Idaeobatis subgenus of 
Rubus. 
Triploid and tetraploid forms are few in number but are a significant 
and characteristic group of raspberries. 
This study suggests that polyploid raspberries are Idaeobatis X Eubatus 
hybrids. 
Polyploidism, if once established in a group, is likely to increase; con¬ 
sequently the breeder attempting interchromosome group crossing will 
find his difficulties increased, the interpretation of results more difficult, 
but the chance of obtaining new combinations of characters multiplied. 
LITERATURE CITED 
(1) American Joint Committee on Horticultural Nomenclature. 
1923. standardized plant names. Prepared by F. L. Olmsted, F. V. Coville 
and H. P. Kelsey. 546 p. Salem, Mass. 
(2) [Beach, S. A.] 
1895. raspberries. In N. Y. State Agr. Exp. Sta. Bui. 91, p. 201-207. 
(3) Blackburn, K. A., and Harrison, J. W. 
1921. THE STATUS OP THE BRITISH ROSE FORMS AS DETERMINED BY THEIR 
cytological behavior. In Ann. Bot., v. 35, p. 159-188, 5 fig., pi. 9-10. 
Literature cited, p. 186-187. 
(4) BlakesleE, A. F., Belling, John, and Farnham, M. E. 
1923. inheritance in tetraploid datura. In Bot. Gaz., v. 76, p. 329-374. 
Literature cited, p. 372-373. 
(5) Card, F. W. 
1917. bush-fruits. New rev. ed., 409 p., illus. New York. 
(6) Darrow, G. M. 
1920. ARE OUR RASPBERRIES DERIVED FROM AMERICAN OR EUROPEAN SPECIES? 
In Jour. Heredity, v. n, p. 178-184, illus. 
(7) Dutrochet, M. 
1832. sterility OF hybrid plants. In Gard. Mag. [London], v. 8, p. 500. 
(8 ) Focke, W. O. 
1910-14. species ruborum. 3 v., illus. Stuttgart. 
(9) Grubb, N. H. 
1922. commercial raspberries and their classification. In Jour. Pomol. 
and Hort. Sci., v. 3, p. n-35, illus. 
(10) Hoar, C. S. 
1916. STERILITY AS THE RESULT OF HYBRIDIZATION AND THE CONDITION OF 
pollen in rubus. In Bot. Gaz., v. 62, p. 370-388, pi. 10-12. Literature 
cited, p. 386-387. 
(11) Laxton, T. 
1874. autumn-bearing raspberry. In Gard. Chron., v. 2, p. 466. 
(12) LonglEy, A. E. 
1923. CYTOLOGICAL STUDIES IN THE GENERA RUBUS AND CRATAEGUS. In Amer. 
Nat., v. 57, p. 568-569. 
(13) Ness, H. 
1921. BREEDING WORK WITH BLACKBERRIES AND RASPBERRIES. In JOUr. 
Heredity, v. 12, p. 449-455, illus. 
