96 GENETICS [Bot. Absts., Vol. IV, 



Morris, Waseca and general averages for all stations. The behavior of a number of Durum 

 varieties is recorded for different Minnesota stations. Treatment is given for oats and their 

 performance for different agronomic characters, such as yield, lodging, date of maturity, qual- 

 ity df grain. Crosses are reported to be made between parental sorts selected because of some 

 particular desired characters. Methods of obtaining homozygous segregates by selection and 

 bulk work are outlined. Mathematical formulae are given for the length of time or number 

 of generations to make a cross automatically homozygous. — Alvin Kezer. 



599. Hayes, H. K., and R. J. Garber. Synthetic production of high-protein corn in rela- 

 tion to breeding. Jour. Amer. Soc. Agron. 2: 309-318. 1919. — The authors believe that there 

 are almost unlimited opportunities of improving corn by an application of the principles 

 learned in inbreeding and crossbreeding. An experiment is outlined for the synthetic produc- 

 tion of high protein corn by self-fertilization, crossing and subsequent selection. Three Fi 

 crosses between high-protein strains were studied in 1918 and were compared with Minnesota 

 Xo. 13 which was the original source of the selfed strains. They gave an increase in average 

 protein content of a little over 2 per cent as compared with Minnesota No. 13 and also yielded 

 better.— F. M. Schertz. 



600. Hayes, H. K., and P. J. Olson. First generation crosses between standard Minne- 

 sota corn varieties. Univ. Minnesota Agric. Exp. Sta. Bull. 183. 22 p., 2 fig. Aug., 1919. — 

 With a series of twelve crosses the authors have found the first generations exceeded the aver- 

 age of their parents, and in many cases the better parent, in yield of grain. In general the first 

 generations were intermediate between the parents in maturity, height of plant, ear length 

 and shelling per cent. The number of rows on the ears, however, were below the average of 

 the parents in flint-dent crosses. The authors state that properly stored two-year-old seed 

 may be expected to yield as well as similarly treated 1-year-old seed and better than 1-year- 

 old seed which is not well ripened. — /. H. Kempton. 



601. Hegner, Robert W. The effects of environmental factors upon the heritable char- 

 acteristics of Arcella dentata and A. polypora. Jour. Exp. Zool. 29: 427-441. 7 fig. Nov. 20, 

 1919. — In studying efficacy of selection as means of isolating heritably diverse lines within a 

 clone of Arcella dentata, and in studying nucleo-cytoplasmic relation in this species and in 

 A. polypora, experiments were performed to determine effects of environmental factors upon 

 heritable characteristics of these organisms. — It was found that underfeeding retards the fis- 

 sion rate from an average of one division every 2.50-day period to one every 4 days; that shell 

 diameter decreased, on the average, 2.68 units of 4.3/i each, and that there was a slight decrease 

 in spine number. — The addition of one drop of sodium silicate to each 100 cc. of water decreased 

 fission rate to same extent as underfeeding. Size is reduced, spines are almost entirely ab- 

 sent and usual brown shell color is replaced by greenish yellow. — Alcohol proved injurious to 

 A. dentata though they are able to grow and reproduce in media containing from 0.25 to 1 per 

 cent alcohol. It retarded fission rate and caused irregularities in shells. — There is some evi- 

 dence that the lower the temperature the smaller become the spines of A. dentata. — Wild speci- 

 mens of A. polypora having a bent oval shell with oval mouth, were found. These, under 

 laboratory conditions, produced entirely normal later generations. The bent oval condition 

 is probably due to unknown environmental factors. — Modifications produced by above envi- 

 ronmental factors persist only so long as those factors are operative; therefore no heritable 

 diversities due to the changed conditions were produced. — A. R. Middleton. 



602. Hegner, Robert W. The relations between nuclear number, chromatin mass, cyto- 

 plasmic mass and shell characteristics in four species of the genus Arcella. Jour. Exp. Zool. 

 30: 1-95. 47 fig. Jan. 5, 1920. — Protozoan genus Am Ua is favorable for genetic research be- 

 cause germinal substratum and somatic characteristics are observable in living specimens; 

 chromatin is in compact spherical mass a1 rent it of nucleus permitting quantitative observa- 

 tions; Arccllas are also able to withstand severe operations. — In Arcella dentata excised 

 portion of shell is not regenerated. Removal of part of cytoplasm is followed in next gener- 



