1919] FIELD CROPS. 33 



those of Wiggang (E. S. R., 3"), p. 135), in that the number of secondary root- 

 lets was by no means constant for any given variety, but varied among indi- 

 viduals so that counts made on a random sample usually gave a frequency 

 distribution represented by a fairly normal curve Furthermore, they con- 

 clude that different varieties of a given cereal show characteristic tendencies 

 in the production of rootlets, and that of the cereals observed this tendency 

 was greater in barley than in either wheat or oats, as indicated by varietal 

 averages, modal numbers, and highest extremes. 



Cereal culture in the Province of Alemtejo, Portugal (Rev. in Compt. Rend. 

 Acad. Agr. France, 3 (1917), Nos. 36, pp. 1049-1051; 41, pp. 1156-1161, figs. 3).— 

 A system of wheat culture known as the " integral method " employed in the 

 arid regions of southern Portugal has been described by J. A. Paquito Rebello. 

 The method is essentially as follows: 



Wheat is sown in the fall (September) in rows 80 cm. (3.15 in.) apart and 

 about 3 cm. deep, at the bottom of a furrow which is allowed to remain open. 

 Before winter a double plow is employed to throw the soil into a rather 

 high ridge in the interspaces, at the same time allowing a little soil to fall 

 hack around the wheat plant. This practice is said to afford the wheat greater 

 protection in the winter, with shallow drainage, and less compacting of the soil 

 from rain, and also favors the development of adventitious roots and tillering. 

 At the close of the winter the field is reduced to one level by harrowing. The 

 grain can be harvested sufficiently early to permit the reseeding of the field to 

 wheat, thus eliminating the fallow year. 



This method is reported to have given average annual yields of 10 hectoliters 

 per hectare (about 11.5 bu. per acre) as compared with a yield of only 8 hecto- 

 liters per hectare every other year under the ordinary methods of cultivation. 



Normal self-fertilization in corn, H. K. Hayes (Jour. Amcr. Soc. Agron., 10 

 (1918), No. 3, pp. 123-126). — This paper, a contribution from the Minnesota Ex- 

 periment Station, describes rather limited observations upon the effects of self- 

 fertilization on yield in corn and upon the relative frequency of self-fertilization 

 in the field. 



Normally pollinated Minnesota No. 13 yellow dent corn gave a yield of 49.3 

 bu. per acre, while 15 Fi self-fertilized lines showed an average yield of 24 bu. 

 Single seeds of Rustler white dent planted in hills some distance apart in a 

 field of Minnesota No. 13 produced 6 ears, the seeds of which were carefully 

 examined and separated into groups composed of 1,911 yellows, 229 doubtful 

 yellows, and 69 whites. The following year a number of hills of the doubtful 

 yellow and of the white groups were grown, and about 25 ears from each group 

 artificially self-fertilized. All of these ears contained a considerable percentage 

 of yellow seeds. 



It is concluded that the first year of self-fertilization in maize causes a 

 reduction of about 50 per cent in vigor, as determined by the yields of shelled 

 corn from normally pollinated and from self-fertilized strains; that if normally 

 5 per cent of the corn in the field was self-fertilized, as indicated by Waller 

 (E. S. R., 37, p. 537), it might be profitable to use seed from detasseled stalks 

 only ; but that the amount of normal self-pollination observed in these tests was 

 found to be less than 5 per cent. 



Linkage in maize: The C aleurone factor and waxy endosperm, T. Bregger 

 (Amer. Nat., 52 (1918), No. 613, pp. 57-61). — This paper, a contribution from the 

 department of plant breeding of Cornell University, presents data on observa- 

 tions made by the author in back crosses of maize plants heterozygous for 

 one aleurone factor and for waxiness with double recessive plants. With ref- 

 erence to the work of Collins (E. S. R., 27, p. 709), containing conclusive evi- 



