Cytogenetic Studies in Solanum, Sect. Tuberarium

I N 1931 the Swedish Seed Association, Svalof, received a collection of potato samples from Bolivia, including diploid, triploid and tetraploid clones.These samples were sent by order of the Swedish explorer, the late Prof. E. NORDENSKIOLD.In a paper entitled »Studies on meiosis in diploid and triploid Solanum tuberosum L.» MtJNTZING (1933 a) published the results of his investigations at the Cyto-Genetic Department of the Seed Association on this potato material.During the years 1932-1934 I was working as assistant to Prof. A. MtJNTZING and then had the opportunity of following his investigations.His potato material was also most kindly put at my disposal for further investigations.The Svalof collection of South American potato species was further supplemented in 1934 by a great number of samples collected by Dr. C. HAMMARLUND in Bolivia and Peru (HAMMARLUND, 1943).By the chief of the Potato Department of the Seed Association, Dr. O. TEDIN, I was kindly permitted to choose from this collection any samples that might be of interest for my own investigations.After a visit in 1937 to the Kaiser Wilhelm-Institut f'iir Ziichtungsforschung, Miincheberg (Mark), the potato-cytologist of this institute, Dr. H. PROPACH, was kind enough to supplement my experimental material by sending me seed of some Solanum species.On the Solanum material thus obtained I have made some investigations mainly concerning the conditions of polyploidy, sterility and incompatibility within the section T'uberarium.It is frankly admitted that in several cases these investigations would have been much improved by a more profound treatment of certain details.Unfortunately, this has sometimes been impossible owing to the dying off of the experimental plants, which under our climatic conditions are rather difficult to cultivate successfully.On the whole, however, the investigations have been planned on a fairly wide basis.Hereditas XX:U.In the Acaulia (see Table 1) the scarcely visible articulation of the pedicel is situated immediately beneath the calyx, and there is no connection between the anthers.According to BUKASOV (1937), this is the youngest group within the section Tuberarium.S. acaule is self-fertile and gives plenty of seed (PROPACH, 1938 a; STELZNER, 1943 b).Tubers are only formed under the conditions of short day (STELZNER and TORKA, 1940).From the Potato Department of the Swedish Seed Association, Svalof', I obtained seed of this species harvested from progenies of plants originating from Bolivia, where this species had been collected by Dr. HAMMARLUND.Through the kind assistance of Dr. E. HULTEN, Lund, this species was found to correspond to S. acaule val'.subexinterruptum BITT.(BITTER, 1912, XI; p. 393).I should here mention that in an earlier paper I unfortunately referred to this species under the name of S. punae Juz.(LAMM, 1943).By JUZEI'CZUK (19:17) S. acaule has been divided into one Peruvian and two Argentinian species.The former, S. punae, according to JUZEPCZUK (1937), is possibly a form of the val'.subexinterruptutn BITT.In S. punae, however, there are about threc segments (2-4) in the odd pinnately-divided leaf.The pedicels are rather hairy and the fruit is violet (.JuzEPCZUK, 1937), while in S. acaule val'.subexinterruptum Brrr.