Specific References 561 



and crossbreeding upon development. Conn. Agric. Exp. Sta. Bull. 207:1- 



100. D. F. Jones. 1939. Continued inbreeding in maize. Genetics 



24:462-473. M. A. Jull. 1936. Superior breeding stock in poultry. 



U.S.D.A. 1936 Yearbook Agric: 947-995. G. Morrison. 1940. The 



fundamentals of seed breeding. Nat. Seedsman, February, 1940. G. 



E. Morrow and F. D. G.ardner. 1894. Experiments with corn. ///. Agric. 



Exp. Sta. Bull. 31:333-360. F. Nilssox. 1934. Studies in fertility 



and inbreeding in some herbage grasses. Hereditas 19:1-162. G. H. 



Shull. 1908. The composition of a field of maize. Kept. Amer. Breeders' 



Assoc. 4:296-301. G. H. Shull. 1909. A pure line method of corn 



breeding. Rept. Amer. Breeders' Assoc. 5:51-59. G. H. Shull. 1910. 



Hybridization methods in corn breeding. Amer. Breeders' Mag. 1 :98-107. 



G. H. Shull. 1922. Ueber die Heterozygotie mit Riicksicht auf 



den praktischen Ziichtungserfolg. Beitrdge zur Pflanzenzucht 5:1-24. 



W, R. Singleton. 1941. Hybrid vigor and its utilization in sweet corn 



breeding. Amer. Natur. 75:48-60. D. G. Steele, 1944. A genetic 



analysis of recent thoroughbreds, standardbreds. and American saddle horses. 



Ky. Agric. Exp. Sta. Bidl. 462:1-27. A. B. Stout. 1929. The clon in 



plant life. J. N. Y. Bot. Gard. 30:25-37. W. G. Whaley. 1944. 



Heterosis. Bot. Rev. 10:461-498. S. Wright. 1922. The effects of 



inbreeding and crossbreeding on guinea pigs. I. and II. L.S.D.A. Bull. 1090: 



1-63. S. H. Yarnell and L. R. Hawthorn. 1938. Breeding tomatoes 



to extend the fruiting season. Proc. Amer. Soc. Hort. Sci. 1938:585-589. 



CHAPTER 24 



A. D. Bergner. 1943. Chromosomal interchange among six species of 



Datura in nature. Amer. J. Bot. 30:431-440. A. F. Blakeslee. 1941. 



Chromosomal interchanges, pp. 37-46 in Cytology, Genetics, and Evolution. 



Philadelphia: University of Pennsylvania Press. A. F. Blakeslee. 



1941. Annual Report of Director of the Department of Genetics. Carnegie 



Inst. Wash. Year Book 40:211-225. A. F. Blakeslee and R. E. Cle- 



land. 1930. Circle formation in Datura and Oenothera. Proc. Nat. Acad. 



Sci. 16:177-183. R. A. Brink. 1927. The occurrence of semi-sterility 



in maize. J. Hered. 18:266-269. C. R. Burnham. 1930. Genetical 



and cytological studies of semisterility and related phenomena in maize. 



Proc. Nat. Acad. Sci. 16:269-277. H. B. Creighton. 1934. Three 



cases of deficiency in chromosome 9 of Zea mays. Proc. Nat. Acad. Sci. 20: 

 111-115. Th. Dobzhansky and A. H. Sturtevant. 1938. Inver- 

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A. C. F.ABERGE. 1940. An experiment on chromosome fragmentations 



in Tradescantia by X-rays. J. Genet. 39:229-248. A. E. Gairdner and 



C. D. D.ARLINGTON. 1930. Structural variation in the chromosomes of 



Campanula persicifolia. Nature, January 18, 1930:1-4. N. Giles. 



1940. Spontaneous chromosome aberrations in Tradescantia. Genetics 25: 



69-87. L. HusTED. 1937. Chromosome breakage and knot formation 



in Paris and Pancratium. J. Genet. 34:329-338. B. McClintock. 



1931. Cytological observations of deficiencies involving known genes, trans- 



