No. 2, xMarch, 19211 HORTICULTURE 143 



941. Whipple, O. B. Line selection work with potatoes. Jour. Agric. Res. 19: 543-573. 

 Sept., 1920. — Data are given on the performance of numerous hill selections made within the 

 Russet Burbank, Rural New Yorker, Green Mountain, and Early Six Weeks potato varieties. 

 The results show that selection is practically valueless in isolating high-yielding strains except 

 during the first season. No definite correlation was found between number of tubers produced 

 per plant and yield in pounds, but high-yielding plants were usually correlated with vigor and 

 health. From the commercial standpoint, the results demonstrate the value of making selec- 

 tions each season and of using vigor and health as an index of productiveness. — Richard 

 Wellington. 



942. WiSTER, John C. Notes on the history of the bearded iris. Jour. New York Bot. 

 Gard. 21: 181-191. Oct., 1920.— A historical sketch of the various Iris breeders from the 

 earliest recorded work to present time. All varieties cultivated prior to 1890 or 1900 were 

 derived from two species, /. pallida and I. variegata. — J. Marion Shull. 



943. Yasui, Kono. Genetical studies in Portulaca grandiflora. Bot. Mag. Tokyo 34: 

 55-65. 1 pi., 1 fig. 1920. — The author describes crosses between single and double races 

 belonging to 7 color types. Doubleness is dominant. Yellow is due to a yellow flavone 

 derivative, which in the presence of a reducing factor {R) yields a magenta anthocyanin. 

 White races lack either the chromogen factor (C) alone or both (C) and (R). Yellow single 

 by white single (CCrr X ccRR) gives magenta Fi (CcRr) and Fj by selfing of 9 magenta, 3 

 yellow, and 4 white. Hybrid double magentas (CcRrDd) by white singles (ccRRdd) give 

 magenta doubles, magenta singles, white doubles, and white singles in equal numbers. By 

 yellow single they give equal numbers of yellow and magenta (CcRrDd X CCrrdd = 

 iCCRrDd : iCcRrDd : iCCRrdd : iCcRrdd : iCCrrDd : iCcrrDd : iCCrrdd : iCcrrdd). 

 Double whites (CcRrDd) by pale yellow singles (CCrrdd) give equal numbers of magenta and 

 yellow doubles and singles. Single scarlet by double white gives magenta double, which 

 mated to single white gives equal numbers of magenta and white doubles and singles. The 

 selfed singles from this give singles only; the selfed doubles, 3 doubles to 1 single. The 

 singles mated to the doubles give 1 : 1 ratio. — L. L. Burlingame. 



HORTICULTURE 



J. H. GouRLEY, Editor 

 FRUITS AND GENERAL HORTICULTURE 



944. FiNDLAY, Hugh. The handbook for practical farmers. 558 p., 258 fig. D. Appleton 

 & Company: New York and London, 1920.— See Bot. Absts. 7, Entry 609. 



945. Alderman, W. H. The status of orchard fertilization experiments. Proc. Amer. 

 Soc. Hort. Sci. 16: 109-113. (1919) 1920.— Attention is drawn to the fact that the orchard 

 fertilization work during the past 30 years in about 30 different experiment stations in this 

 country has all been carried on in about the same general way. The information obtained 

 up to the present time about which there is little contention narrows down to about four 

 general headings; namely, (1) there are many apple orchards, growing under a wide range of 

 conditions which do not respond to any fertilizer ; (2) orchards in sod are most likely to respond 

 to fertilizers; (3) starved orchards give a ready response to fertilization; and (4) nitrogen in 

 a readily available form seems to be the only element of plant-food that is uniformly a factor 

 in the favorable responses— when such are secured. The author states, "We may readily see 

 and safely say that a normal plant probably has a definite arrangement of conditions within 

 itself, which fit into its functions of growth and fruitage or reproduction. It is when the 

 arrangement is distributed that we get reduced vigor, feeble growth or lack of productive- 

 ness." He suggests that either pruning, cultural methods, fertilization, or some combination 

 of all of these may restore the normal optimum in the plant and produce the results desired. 

 Instead of a fertilizer problem, the problem may be one of pruning or cultural practices, or a 



