Varietäten, Descendenz, Hybriden. 57 



Pritchard, F. J., Some recent investigations in Sugar- 

 beet breedino. (The Botanical Gazette. LXII. p. 425 — 465. 51 

 Fig. 1916.) 



The results of this paper are summarized as follows: 



Differences in the size and sugar content of individual beet 

 roots show no evidence of inheritance. They are fluctuations, there- 

 fore, and apparently play no part in beet improvement. 



No correlation was discoverable between percentage or quantity 

 of sugar in sugar-beet roots of ordinary sizes and their yield of 

 seed, nor between their yield of seed and the average percentage 

 of sugar in their progeny. 



The fluctuations of beet families planted in progeny rows in 

 alternation with check rows exceeded their real differences, but 

 real differences were distinguishable b}^ the use of a large number 

 of replications. 



Areas of beets in an apparently uniform field of small dimen- 

 sions showed a difference of 2 per cent sugar. 



Percentage of sugar and yield of sugar of sugar-beet rows vary 

 independently. Progen}'' rows should be graded on both percentage 

 and yield of sugar, therefore, or on yield of extractable sugar. 



The average weight of root per row increases with yield of 

 sugar and decreases with percentage of sugar. 



The discontinuance of selection for one generation caused no 

 deterioration in percentage of sugar. The fact, there was some 

 apparent gain. 



No improvement in yield or percentage of sugar was obtained 

 by continuous selection. Both the good and the poor families trans- 

 mitted average qualities. Jongmans. 



Vries, H. de, New dimorphic mutants of the Oenotheras. 

 (The Botanical Gazette. LXII. p. 249-280. 5 Fig. 1916.) 



Besides Oenothera scintillans, which splits under ordinary cir- 

 cumstances in every generation into nearly equal groups of plants 

 of the same type and others of the type of O. Lamarckiana, the 

 author has cultivated pedigree families of four other mutants of O. 

 Lamarckiana which behave in the same manner. They have been 

 designated as O. cana, O. pallescens, O. Lactuca, and O. liquida. 

 Their Laniarckiana-hke offspring are constant in their progeny. 

 Besides the two main types, they produce, as a rule, a relatively 

 high percentage of other mutants. 



The specimens of the parental type are on the average pro- 

 duced in about 40 per cent, the other 60 per cent heing Lamarckiana 

 with some mutants; but these figures vary with the cultures and 

 with the plants according to their individual strength. They may 

 even increase, on very slrong biennials, to 93—97 per cent for the 

 parental type. 



Dimorphic mutants of this type occur also in allied species ot 

 the biennis group, as has been discovered by Bartlett in the case 

 of O. stenotneres mut. lasiopetala and described in this article for O. 

 biennis Chicago mut. saligna. 



In the crosses with older species or with O. Lamarckiana and 

 its derivatives, O. cana follows exactly the type of the analogous 

 crosses of 0. scintillans and 0. lata. 



In the dimorphic mutants, the special characters are handed 

 down to the next generation through the ovules only. The pollen 



