22 GENETICS [BoT. Absts.. Vol. VII, 



GENETICS 



G. H. Shull, Editor 

 . J. P. Kelly, Assistant Editor 



157. Anonymous. [Rev. of: (1) Harrison, J. W. Heslop. A preliminary study of the 

 effects of administering ethyl alcohol to the lepidopterous insect, Selenia bilunaria, with par- 

 ticular reference to the offspring.- Jour. Genetics 9: 39-52. Dec, 1919. (2) Duerden, J. E. 

 Methods of degeneration in the ostrich. Jour. Genetics 9:131-193. PI. 5-6, 8 fig. Jan., 

 1920.] Nature 104:609. 1920. 



158. Anonymous. Vagledning pa forsSksfSlten 1920 vid Svalof och filialerna. [Guide to 

 the experimental fields of Svalof and its branch experimental stations, for the year 1920.] 

 1.45 X 200 mm., 52 p., 1 map. Landskrona, 1920.— Pamphlet intended as a manual for visitors. 

 During this year 14,059 plots (of which 94 are mass-cultures) have been laid out.— -K". F. 

 Ossian Dahlgren. 



159. Bach, Siegfried. Zweierlei Weisslinge bei Mais. [Two kinds of albinos in maize.] 

 Zeitschr. Pflanzenzlicht. 7:238-241. June, 1920.— From open-pollinated ears of maize, the 

 author reports the occurrence of two types of albinistic seedlings. One ear produced 170 

 green and 4 pure white seedlings, the latter dying within a month's time. The other ear 

 produced 160 green and 5 partially green (striped) plants which died in two months. The 

 low proportion of albinistic seedlings is due to random open-pollination with a small amount 

 of natural self-pollination. Author assumes that chlorophyll content in maize is dependent 

 upon at least two pairs of factors, XX and Y Y; and that the parent ears noted above had the 

 genotypic formulae XX Yy and XyYY respectively.—^. W. Lindstrom. 



160. Baumann, E. Beitrage zur Kenntnis der Rapspflanze und zur Ziichtung des Rapses. 

 [Contributions to a knowledge of the rape plant and to the breeding of rape.] Zeitschr. Pflanzen- 

 zlicht. 6: 139-184. 2 figs. Dec, 1918.— A program for improving the rape plant was fol- 

 lowed through a period of nine seasons (1909-1917), together with a study of the inheritance of 

 certain characters influencing the performance of the plant under a variety of weather con- 

 ditions. Of the qualities concerned in making for a larger gross yield, and greater desira- 

 bility of product, the adaptation of different varieties to climate, particularly with reference 

 to the time of resumption of growth in spring and the latest occurrence of spring frost, was 

 found to be of much practical importance. Of primary interest, also, were found the capacity 

 of varieties to resist insect attack, and to occupy gaps in the stand by the development of 

 branches. A detailed study of external morphology showed that the taller the plant, the 

 greater was the number of internodes, and the higher the insertion of the latter on the axis. 

 The increase in length of lateral branches of the first order from tip toward base begins as a 

 straight line function, but toward the end is lessened considerably. A similar relation 

 obtains in the case of branches of the first and higher orders. Generally, in plants having a 

 long axial stem, the prunary and secondary branches are shorter, and the inflorescence more 

 crowded.- Plants of the higher continuity states, possess in a larger measure the qualities 

 making for increased productivity, as the different morphological elements tending toward 

 greater yield are more numerous and better differentiated. Adaptation to a particular cli- 

 mate is largely contingent on the capacity to form a vigorous healthy growth in fall, and to 

 develop shoots rapidly in spring, through which damage by late frosts and insects is resisted. 

 An excessively vigorous growth, on the other hand, may bring about a spindling condition, 

 encourage decay, and render the crop more subject to late spring frosts. In all cases, varie- 

 ties and races requiring the longer periods for maturing gave the greater yields. The per- 

 formance of species or genera making for adaptability to climate is an expression of the 

 irritability of its cells to thermal stimuli. The importance of physiological data derived from 

 breeding experiments to the ecology and the distribution of plants is emphasized.— C/iar/es 

 Drechsler. 



