NOTES ON SOME HYBRID TUBEROUS SOLANUMS. 



53 



NOTES ON SOME HYBRID TUBEROUS SOLANUMS. 

 By Rev. J. Aikman Paton, M.A., B.Sc. 



In the summer of 1907, among other crosses, I effected two on S. Maglia, 

 the white-flowered Chilian wild potato. Twenty-five berries were formed 

 and grew (pollen of several different varieties, wild and cultivated, being 

 used), but of these only two were found to contain sufficiently matured 

 seed — one seed in each berry. The pollen parents were (1) S. " etuberosum " 

 (so-called),* and (2) a Chilian cultivated variety (Francesa Col). The 

 two resulting seedlings showed a marked difference from the beginning, 

 the former being much more vigorous. 



(1) S. Maglia x S. "etuberosum": sown March 28, 1908; first 

 flower July 1, first berry July 6 (thirty-one berries altogether) ; taken up 

 December 7 ; tubers white [«]. 



This seedling, a very strong one, resembles S. "etuberosum " in 

 having a green stem and soft foliage, but the leaflets are much larger, like 

 those of the cultivated sorts, from which, indeed, they cannot be dis- 

 tinguished. (The foliage of the parents is quite distinct, and in each case 

 distinct from that of the cultivated forms.) The plant has the branching 

 habit of S. Maglia fully developed, almost every node for a good way 

 up the stem producing a branch. The leaves seem immune from 

 attack by the fungus Phytophthora infestans. The corolla is large, 

 measuring about two inches from tip to tip — very much larger than that 

 of either parent — mid-violet in colour, with white tips. (S. Maglia has 

 pure white flowers, S. " etuberosum " pale lavender (No. 207, l),t with violet 

 tinge on back rays.) The trusses are very large and abundant. The 

 stamens are large and finely formed, straight (those of S. Maglia are 

 usually curved inwards) like those of S. "etuberosum," but much larger, and 

 full of fertile pollen. The style very slightly projects beyond the stamens. 

 Thirty-one berries have formed on the plant, all due to artificial pollin- 

 ation. The berries are unlike those of either parent, being large, round, 

 of a beautiful green colour (No. 243, 4, shading to No. 271, 2 and l),f with- 

 out spots, quite like the common potato berries. (S. Maglia has laterally 

 compressed round berries ; S. "etuberosum " has ellipsoidal white-spotted 

 berries, and in both they are much smaller than those of the hybrid. The 

 tubers are in colour quite white (those of S. Maglia are violet (No. 191),f 

 those of S. "etuberosum" brownish-yellow-white), but of the same 

 shape (although this varies greatly) as those of S. Maglia. They occur 

 at the ends of short runners, as in some cultivated forms. 



I have effected a number of crosses with the pollen of this hybrid on 

 cultivated varieties, e.g. ' Jeanie Deans,' 1 Duchess of Cornwall,' ' Eldorado,' 

 ' Ninetyfold,' 'Peacemaker,' &c, showing that it is quite fertile. The 

 seeds produced as a result of these crosses have been sown. 



* Its " selfed" seedlings seem to show that this is a hybrid. (See note p. 56.) 

 t These numbers refer to the colour numbers in the Repertoire des Couleurs. 



