Junk, 1920] GENETICS 315 



2124. Fischer, Ed. [Rev. of; Ki-huaiin, H. Impfversuche mit Pfropfbastarden. ^In- 

 fection experiments with graft hybrids.) Flora 11-12: 418-430. 1918.] Zeitschr. Hot. 10: 

 7G5-766. 1918. 



2125. Fheeman, G. F. A mechanical explanation of progressive changes in the proportion 

 of hard and soft kernels in wheat. Jour. Aincr. Soe. Agron. 10: 23-28. Jan., 1918. — The ten- 

 dency of high gluten wheats to become low gluten wheats, that is, the tendency of a corneous 

 endosperm to become mealy, is attributed to progressive selection. A positive correlation 

 was found between hardness or corneousness in Durum wheat and yield. A negative corre- 

 lation was found between hardness or corneousness and yield with all other varieties tested 

 at Yuma. In other words, under the hot southern climates hard Durum wheats are the high 

 yielders. Consequently, the hard strains under climatic selection tend to increase. On the 

 other hand, in other strains, the bread and Poulards, the hard strains, yield much less than 

 the soft strains. This difference in a period of years results in a considerable climatic selec- 

 tion, sufficient in a ten-year period to convert a hard Turkey into a soft Turkey by the gradual 

 increase brought about by the differences in yield by soft and hard strains within the type. 

 The possibility of overcoming this tendency is suggested by means of isolating pure strains 

 by individual plant selection and later propagation if there is apparently no change within 

 the strain itself. The change is brought about by the more rapid propagation of one group 

 of strains (soft) as compared with a less productive group of strains (hard). — Alvin Kezer. 



2126. Gertz, O. Panachering hos Mercurialis perennis L. En morfologisk, anatomisk 

 och mikrokemisk studie. (Mit Zusammenfassung und Figurerklarung in deutscher Sprache.) 

 [Variegation in Mercurialis perennis L. A morphological, anatomical and microchemical study. 

 (With summary and explanation of figures in German.)] Bot. Xotiser 1919: 153-164. 22 fig. 

 1919. — The author describes a form with white-tinged leaves from Torup in Skane (Sweden). 

 The epidermal cells of the white parts of the leaves lack the undulation of the cellwalls and 

 are always smaller than those of the green parts. Several anomalies of the stomata were ob- 

 served. The green parts of the leaves were 2.1-1.5 times as thick as the white ones and have 

 larger intercellular spaces. The blue color of the leaves that is often to be observed in dried 

 specimens of Mercurialis is due to an oxidation process. Author promises further investi- 

 gation, also from genetical point of view. [See Bot. Absts. 4, Entry 1557.] — K. V. Ossian 

 Dahlgren. 



2127. Gonzalez Rios, P. La produccion de nuevas variedades de cartas. [The production 

 of new varieties of sugar cane.] Rev. Agric. Puerto Rico 2: 29-38. 8 fig. 191S. — Chief aim 

 in producing new varieties is to combine characteristics and indispensable qualities of good 

 cane considered in two aspects. — A. For cultivation: 1. Germinating power. 2. Resistance 

 against excessive rains or drouth. 3. Growth habit, erect or sprawling. 4. Resistance 

 against fungous or insect diseases. 5. Length of growing period. 6. Tonnage. 7. Power 

 of rattooning. — B. For the factory: 1. Characteristics of the canes. 2. Quality and quan- 

 tity of bagasse, whether brittle or flexible. 3. Juicy or dry. 4. Richness of juice. 5. Purity 

 of juice. — Problem is to produce varieties by crossing which are adapted to various conditions 

 obtaining in different localities. Botanical characters of inflorescence described. Flowers 

 usually perfect but sometimes panicles contain only male or female flowers. Hybridization 

 is done in various ways. 1. Planting varieties alternately, a row or one kind and a row of 

 the other, or alternating the stools. Wind will transfer pollen and effect natural crossing. 

 2. Enclosing flower-stalks of both parents, while in situ, together in small cloth bag. 3. A 

 bagged flower-stalk may be severed and placed in contact with flowers of another growing 

 one. This method has the disadvantage that viability of pollen quickly deteriorates due to 

 humidity or dryness. All these methods produce seedlings and the majority are hybrids. 

 19 of 30 crosses were successful, giving 1589 seedlings. Seeds are described as to size, shape 

 and morphology. Sowing, transplanting and general culture of seedlings are detailed. 

 Selections are made before maturity, based on number and size of canes, regularity of diam- 

 eter, high per cent of sucrose, scarcity of fiber, resistance to fungous and insect diseases, 

 etc. — E. Eugene Barker. 



