Åke Gustafsson

Linnaeus' Peloria: The history of a monster

SummaryThe so-called Peloria case has been discussed repeatedly in world literature since the discovery of the five-spurred Linaria in 1742 and its description by Linnaeus in 1744. In 1742 a young Uppsala botanist found a peculiar specimen of the common toad-flax (now named Linaria vulgaris L.) on an island in the Stockholm archipelago. The plant, which had spread vegetatively, possessed five spurs instead of one spur, a characteristic of the common toad-flax. The material was presented to Linnaeus, who became quite excited. The finding was contrary to his concept that genera and species had universally arisen through an act of original creation and remained unchanged since then. In a famous thesis of 1744, Linnaeus called the deviating plant ‘Peloria’, Greek for ‘monster’. The case of pelorism was discussed later on by a great number of famous writers and scientists including, for example, Goethe, Darwin, Naudin, De Vries and Stubbe. Parallel types were found in numerous species of other genera and families. Such aberrant forms are caused by spontaneous mutation. The history, mode of origin, morphology, inheritance and distribution of different Peloria mutants are discussed in the paper.

Induced mutations and barley improvement

SummarySeven barley varieties, originating from three X-ray induced mutations, have been officially approved in Sweden since 1958. Some have gained a wide area of cultivation. The list is as follows: Pallas, isolated 1947, approved 1958, mutant ert-k32 of Bonus barley. — Mari, isolated 1950, approved 1960, mutant mat-a8 of Bonus. — Hellas, approved 1967, mutant cross of Pallas × Herta. — Kristina, approved 1969, mutant cross of Domen × Mari. — Visir, approved 1970, Pallas × Long Glumes back-crossed to Pallas. — Mona, approved 1970, mutant cross of Mari × Monte Cristo back-crossed to Mari. — Gunilla, approved 1970, hybrid cross of the mutant 44/3 arisen from Gull barley in 1939; evolved in a series of steps, using one six-row and four two-row varieties, with mutant characters prevailing and Gull genes reiterated. — After the first approval of Pallas in 1958, 12 more years have led to the approval of a second mutant case and five mutant crosses. In addition, chromosome translocations, induced by irradiation in Bonus, have been instrumental in the production of hybrid barley in USA and are used in the barley improvement program of Sweden, as well as for theoretical analysis in numerous countries.

Phytotron cultivation of early barley mutants

ConclusionsThe authors have tried to gather data which permit some information on the between and within locus reactions of induced early barley mutants to different photo- and thermoperiods. Eight mutant cases, showing rather drastic earliness in field cultivation and representing three different gene loci, were examined in phytotron experiments according to routine methods of cultivation. One of the mutants, mat-a8, has been released as an original Swedish barley variety under the name of Svalöfs Mari. In a previous publication (Dormling et al., 1966) this mutant was compared to its parent variety, Svalöfs Bonus, under 30 different climatic conditions. In the present investigation three photoperiods (24, 16 and 8 hours of artificial light) were combined with three suitable thermoperiods (20-15°, 20-10° and 15-10°C).The results indicate that photoperiodic insensitivity, with regard to ear formation and heading capacity, as well as kernel production, is of rather frequent occurrence in connection with drastically early mutants in barley. Four out of eight induced mutants give a more or less pronounced insensitivity. Three of the four insensitive mutants represent locus a, one belongs to locus b. Of the two c-mutants none was insensitive; both were on the contrary pronounced long-day types.Photo- and thermoperiods interact in various ways. This is especially clear in the c-mutants just mentioned, which have a high generative productivity and efficiency at continuous light and high thermoperiods. They produce no grain but considerable vegetative matter at 8 hours of light, independently of thermoperiod, as well as at 16 hours of light with high temperatures. In fact, mutants of loci a and c differ strikingly with regard to their relations to the climatic conditions applied. The insensitive mutant b13 is remarkably similar to the mutant a12, but its resemblance to the sensitive mutants b7 and b10 of the same locus is evidenced by its high average internode number.It ought to be pointed out here that the mutants of the three gene loci analysed in this study can be distinguished phenotypically with regard to morphological as well as physiological properties, in the field as well as in phytotron cultivation. The c-mutants are especially characteristic. However, there also seem to be clear differences in reaction between the allelic mutants of a locus. In fact, all eight mutants studied seem to react more or less differently.The insensitive mutant a8, which has been released into practice, is also widely used in recombination work, and successful segregates have been isolated. The characteristics of a8, which make the mutant valuable in practice, are also found in phytotron experimentation, specially with regard to earliness, generative efficiency and yield. Also the semidwarf habit and the insensitivity to changes in photo- and thermoperiods readily show up.

Population Research in the Scandinavian Scots pine (Pinus sylvestris L): Recent Experimentation

Since the turn of the century population research, in the form of provenance experiments, has been in the foreground of forest genetics and breeding. The use and distribution of hardy and well-growing materials has formed an important object in advanced forestry practice. Norway spruce (Picea Abies (L.) Karst.) and Scots pine (Pinus sylvestris L.) are the two valuable conifer species in northern Europe. The background of work and the results have been discussed by numerous scientists. References are here made especially to papers by Langlet and by Eiche (see references).

Yield efficiency of the X-ray mutant svalöf's ‘pallas barley’

SummarySvalöfs Pallas barley is an X-ray mutant of the high-yielding Bonus barley variety. Both varieties were released by the Swedish Seed Association, Svalöf, and have gained wide distribution. Pallas barley arose as an erectoides mutant in 1947. After careful testing it was approved in 1958 as an original Swedish variety. It soon became widespread over great parts of western Europe owing to its high productivity, pronounced lodging resistance and high nitrogen utilization.Danish tests of barley varieties are recorded and published yearly. From 1958 when Pallas entered the Danish trials, and up to and including 1964, its parent Bonus barley was the official Danish standard variety. In 1965 it was replaced by Pallas barley. A careful biometrical comparison of the two varieties has been made with regard to grain yield, lodging resistance, straw height and strawproduction. In addition, the influence of increased lodging resistance on yield as well as the variance of yield and lodging have been analysed.ZusammenfassungDie Gerstensorte Svalöfs Pallas geht auf eine im Jahre 1947 entstandene röntgeninduzierte erectoides-Mutante der ertragreichen Sorte Bonus zurück. Beide Sorten wurden von dem Schwedischen Saatzuchtverein in Svalöf gezüchtet. Nach eingehender Prüfung wurde sie 1958 als schwedische Zuchtsorte zugelassen und erlangte durch ihre gute Ertragsfähigkeit, die wesentlich verbesserte Standfestigkeit und gute Stickstoffverwertung weite Verbreitung in großen Teilen Westeuropas.Die Ergebnisse der dänischen Gersten-Sortenprüfungen werden alljährlich veröffentlicht. 1958 wurde Pallas erstmalig in diese Versuche einbezogen, bei denen bis einschließlich 1964 ihre Ausgangssorte Bonus als offizielle Standardsorte diente. Sie wurde 1965 durch Pallas ersetzt. Beide Sorten wurden in bezug auf Ertragsfähigkeit, Standfestigkeit, Strohlänge und Strohertrag sorgfältigen biometrischen Prüfungen unterzogen, weiterhin wurden der Einfluß erhöhter Standfestigkeit auf die Ertragsfähigkeit untersucht sowie Ertrags- und Standfestigkeitsvarianzen geschätzt.