THE RESULTS OF FURTHER BREEDING 

 EXPERIMENTS WITH PETUNIA 



EDITH R. SAUNDERS 

 Lecturer, late Fellow, Newnham College, Cambridge, England 



In view of the present discussion on the inheritance of 

 doubleness in Petunia 1 and pending further investiga- 

 tion of the evidence in favor of an explanation based 

 wholly or in part upon selective sterility such as has been 

 described by Geerts 2 for Oenothera Lamarckiana, by 

 Belling 3 for the Velvet "Bean" {Stizolobium deeringi- 

 anum and other species) and by East 4 for species of Nico- 

 tiana, it seems desirable to make available the further 

 results of the breeding experiments which have been car- 

 ried out since the publication of the earlier data in 1910. 5 

 The two main facts established by the earlier work were 



(1) That singles of the cultivated forms of P. violacea, 



P. nyctaginiflora and of various garden strains 

 (Countess of Ellesmere, hybrida grandiflora and 

 others) give only singles when self-fertilized or 

 crossed with pollen of other singles. 



(2) That these same singles give a mixture of singles and 



doubles in Fj when crossed with the pollen of a 

 double. 



The later experiments carried out on the same lines and 

 with the same kind of material have considerably widened 



i Frost, "The Inheritance of Doubleness in Matthiola and Petunia," 

 Am. Nat., Vol. XLIX, No. 586, p. 623, Oct., 1915; also Saunders, "Selec- 

 tive Partial Sterility as an Explanation of the Behaviour of the Double- 

 throwing Stock and the Petunia," Ibid., Vol. L, No. 596. 



2"Beitriige zur Kenntniss der Cytologic und der partiellen Sterilitat von 

 (Enothera Lamarckiana," Beeueil ties Trav. Bot. Neerl, Vol. 5, 1909. 



3 "The Mode of Inheritance of Semi-sterility in the Offspring of Certain 

 Hybrid Plants," Zeitsch. f. ind. Abst. u. Vererbungslehre, Bd. XII, Heft 

 5, p. 303, 1914. 



*"The Phenomenon of Self-sterility," Am. Nat., Vol. XLIX, No. 578, 

 p. 77, Feb., 1915. 



'Saunders, "Studies in the Inheritance of Doubleness in Flowers," I. 

 Petunia. J. of Genetics, Vol. I. No. 1, p. 57, 1910. 



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