STUDIES ON THE CHROMOSOME NUMBERS OF SOME SPECIES IN SOLANACEAE Kanemasa TOKUNAGA INTRODUCTION In Capsicum annuum, there are many garden varieties showing 12 chromosomes in haploid and 24 in diploid (Vilmorin et Simonet, 1928, Huskins and La-Cour, 1930, Yarnamoto and Sakai, 1932). In Solarium ll~telongena, the same number of chromosomes was also observed in a number of garden varieties (Kojima, 1925, Vilmorin et Simonet, 1928). Kostow reported in 1926 however, that the haploid number in Capsicum annuum was 6. If there actually exist 6 chromosome plants in this species, we might account for 6 as the basic number. Further studies seem to be necessary in regard to the chromosome number in this species as well as in other species in Solanaceae. IIr- the present study, the writer counted the chromosome numbers in 49 garden varieties of Capsicum annuum and 37 such of' Solanum Melongena, together with those of some other genera in Solanaceae. One species in Phy.calis was found to be autotetraploid. The writer expresses his sincere thanks to Prof. F. Kagawa for his valuable suggestions and guidance in the work. I am also indebted to Mr. N. Hasegawa and Mr. Y. Chizaki for their kind help. MATERIALS AND METHODS The plants that provided the materials were raised from the seeds obtained from the Tokyo Koishikawa Botanical Garden and from various sources home and abroad. These plants were cultivated in the experimental garden of the laboratory of Utsunomiya Agr. College. The number of chromosomes was counted by means of Belling's acetocarmine in P. M. C.'s. The preparations made by this method were quite suited for the chromosome observation in these plants, and they have kept themselves clear for weeks. RESULTS OF OBSERVATION The reduced numbers of chromosomes I have ascertained are shown in the following table (Table i), and the chromosome figures can be seen in Figs. 1-107.
232 TOKUNAGA-CHROMOSOME NUMBERS IN SOLANACEAE Thus, in a large number of garden varieties of Capsicum annuum as well as in other species of Solanaceae, no plant was found to show n=6. The TABLE 11) 1) The material plants of Capsicum annuum and Solanurn Melongena were of various sources. So that it seems not impossible to recognize some of them with different names to belong to the same or similar race, though more, or less difference of characters was shown. But the plants are tabulated here provisionally according to their practical names. 2) All figures are drawn by the aid of Abbe's camera using Leitz i/12 oil immersion and io x cgmpensation ocular under the magnification X 165o, and they are reduced to 4/5 in reproduction. They are all of the first metaphasic chromosomes in polar views except Figs. 32, 34, 36, 45, 47, 88, 89, 93, 94 and 96-98, which show the second metaphasic ones.
TOKUNAGA- CHROMOSOME NUMBERS TN SOLANACEAE 333 Figs. 1-48. Capsicum aunuun
234 TOKUNAGA-CHROMOSOME NUMBERS IN SOLANACEAE
TOKUNAGA-CHROMOSOME NUMBERS TN SOLANACEAE 235 Fig. 49. Capsicum annuunz; Figs. 5o-86. Solanum Blelongena; Figs. 87-90. Different species of Solanzan. haploid number of chromosomes was found in most cases to be 12 in different species and their garden races in Capsicum, Solanum, Datura, and in certain species of Physalis. The haploid numbers io and 24 were found in different species in Nicotiana and 36 in Solauum nigrum.
236 TOKUNAGA-CHROMOSOME NUMBERS IN SOLANACEAE In Physalis pubescens, P. angulata, and Solanum miniatum 24 was found as the haploid number. Vilmolin et Simonet (1928) reported the reduced number of P. pubescens to be 12, but my counts are different. According to Nakajima (1931), P. angulata has 12 haploid chromosomes and 24 was reported as its haploid number by Yamamoto and Sakai (1932). My result was the same as that of the latter investigetors, though my materials were obtained from plants growing in the campus of our College where the materials of Nakajima were taken a few years ago. It may be supposed that in Physalis pubescens, P. angulata,. Solanum miniatum there are different forms having unequal number of chromosomes, but we have no means to identify the material plants with those investigated by other authors. The forms having the chromosome numbers such as were reported by Vilmorin et Simonet and Nakajima were not found though a' number of different individuals were observed in each species. As mentioned above, the basic number of chromosomes is 12 in Physalis and also in Solanum. So that, Physalis pubescens, P. angulata and Solanum miniatum which were observed by the writer to have 24 chromosomes in haploid are tetraploid plants. In Physalis pubescens, in both the diakinesis and first metaphase, there are often 12 quadrivalent chromosomes each consisting of four chromosomes
TOKUNAGA.-CHROMOSOME. NUMBERS IN SOLANACEAE 237 (Fig. 105). But the number of quadrivalents becomes frequently smaller as some of them are separated into 2 sets of bivalents. In these cases the sum of the number of the quadrivalents and that of bivalents in a P. M. C. surpasses 12 (Fig. 106). And in some cases, probably in later metaphase, 24 bivalents are observed (Fig. 107). We may be able to say that this form of P. pubescens is an autotetraploid. This form may have been derived from an original diploid form by the doubling of chromosomes. Figs. 91-95. Different species of Solanu,n ; Figs. 96. 97. Two species of Datura ; Figs. 98, 99. Two species of Nicotiana; Figs. too-107. Different species and varieties of P/avsalis. 105-107, P. pubescens ; 105, 12 quadrivalents ; 106, 6 quadrivalents and 12 bivalents ; 107, 24 bivalents. SUMMARY i. The haploid numbers of chromosomes in a number of species and garden varieties of Capsicum, Solanum, Physalis, and other genera in Solanaceae were determined. 2. 49 garden varieties in Capsicum annuurn, 37 such in Solarium Melona ena, 6 other species in Solanum, 3 species in Physalis and 2 species in
238 TOKUNAGA-CHROMOSOME NUMBERS IN SOLANACEAE Datura were observed to present 12 chromosomes in haploid. Different numbers were also observed in some other plants studied. 3. A form of Pliysalis pitbescens showing n = 24 was found, and it was recognized, from its chromosome configulations in the meiosis, to be an autotetraploid. LITERATURE CITED (March, 1933 Utsunomiya) Belling, J. and Blakeslee, A. F. (1923). The reduction division in haploid, diploid, and tetraploid Datmuas. Proc. Nat. Acad. Wash., Vol. 1g. Darlington, C. D. (1931). Meiosis in diploid and tetraploid Primula sinensis. Jour. Genet. Vol. 24. Huskins, C. L. and La-cour, L. (19J0). Chromosome numbers in Capsicum. Amer. Nat. Vol. 64. Kojima, H. (1925). On the meiosis and chromosome numbers in different races of Solanum Melon- Apia L. Bot. Mag. (Tokyo) Vol. 39. Kostow, D. (1926). Die Bildung der Pollenkorner bei einigen Varietaten von Capsicum annum. Jahrb. d. Univ. Sofia. Vol. 4. (Cited from Huskins, C. L. and La-cour, L. 1930. Chromosome number in Capsicum. Amer. Nat. Vol. 64.) Nakajima, G. (1931). The chromosome number in cultivated and wild angiosperms. Bot. Mag. (Tokyo) Vol. 45. Vilmorin, R. De. et Simonet, M. (1928). Recherches sur le nombre des chromosomes chez less Solanees. Zeits. f. Ind. Abst.- u. Vererb. Suppl.- bd. 2. Yamamoto, K. and Sakai, K. (1932). On the chromosome number in some Solanaceae. Jap. Jour. Genet. Vol. 8.