130 



SCIENTIFIC AGRICULTURE. 



December, 1921. 



white and one red-flowering plant, Gmelin 

 (2. p. 417) obtained different results in 

 two different cases. In one case he ob- 

 tained a progeny composed exclusively of 

 red-flowered individuals, the result of 

 course clearly indicating dominance of 

 red over white. In the other case, both 

 the red-flowered and the white-flowered 

 component of the inter-crossed pair pro- 

 duced white flowered offspring. The form- 

 er produced 58 plants of which 29 were red- 

 flowered and 29 white-flowered. The lat- 

 ter produced a progeny of 258 individ- 

 uals of which 155 were red-flowered and 

 103 white-flowered. In this case the ap- 

 pearance of the white-flowered plants 

 in the progeny was evidently due to the 

 fact that tjie red-flowered parent plant 

 was heterozygous for the red colour. 



Taking all evidence into consideration 

 the dominance of red over white in the 

 flowers of Red clover may be considered 

 satisfactorily proven. 



Concerning the blue-colored Red clover 

 flowers, results obtained by Kajanus (3. 

 p. 764) seem to indicate that the blue 

 colour is recessive to red. 



The Grenetic Complexion of the Red 

 Colour: — -The information available on 

 the genetic complexion of the red colour 

 is so far rather scant. It has been studied 

 by Kajanus in progenies of plants having 

 red flowers " of different shades and by 

 Gmelin in connection with the develop- 

 ment of white-flowered plants from red- 

 flowered parents. 



Kajanus (3. p. 765-66) came to the con- 

 clusion that intensive colouring expresses 

 a more complicated genetic constitution 

 than does light colouring, and that the 

 segregation in deep red and light red 

 colour types as found in the progenies 

 studied indicates the presence of two 

 Mendelian factors for red. 



Gmelin (2. p. 423) arrived at a similar 

 conclusion; only he intimates that in all 

 probability several, i.e., more than two, 

 factors for red may occur. 



The inheritance of the white colour:— 

 Having found that tlie white colour does 

 not dominate over the red, Gmelin (2. 

 p. 416) undertook to investigate the pos- 

 sibility of developing a constant white- 

 flowering variety. He selected for the 

 purpose two white-blossomed individuals, 

 isolated them together, and then inter- 



crossed them by means of bumble bees. He 

 thv.'s ' obtained ae^d from, both plants 

 which later was sown. From one of the 

 plants he obtained a progeny of about 

 210 individuals, all with white flowers. 

 From the other about 450 individuals 

 were secured of which all flowered white 

 except two which had red blossoms. In 

 the latter case, however, Gmelin observed 

 that th^ two red-flowering individuals 

 were of a quite different type in general 

 than the others, i.e., those which had 

 white flowers. Indeed, their appearance 

 and their morphological characteristics 

 were so strikingly different that he con- 

 eluded that they must have been the re- 

 sult of accidental crossings; the humble 

 bees used for the pollination of the isol- 

 ated plants presumably have carried a 

 few pollen grains from outside plants 

 with them when set to work inside the 

 isolation cage. 



However that may be, Gmelin ^as con- 

 clusively shown that it is comparatively 

 easy to develop constantly white-flower- 

 ing red-clover varieties. 



The. inheritance of the blue colour: — 

 As already mentioned, blue-flowered red 

 clover plants were first observed by Ka- 

 janus in the so-called Toten clover fro™ 

 Norway. In the year 1911 a total of 7 

 blue-flowering plants were observed. 

 Their seed was harvested separately and 

 the following spring the seed of three of 

 them was sown, with the result that late 

 in the fall a total of 372 flowering plants 

 were obtained which produced red and 

 blue flowers as follows : 

 No. of No. of 

 red- blue- 

 flowering flowering 



No. plants, plants. Total Relation 



Average Relation 20.9 :1 

 KojaxKfi later succeeded in propagating 

 the blue type and states (5. p. 3) that in 

 1914 he had "quite a large number of 

 such plants." 



The Characters of the Seed. 

 The. variation in colour: — Commercial 

 samples of rod clover seed show, as is well 

 known, a very great variation in respect 



