536 EXPEEIMENT STATION RECORD. [Vol.37 



An average increase of 40.87 bu. per acre was thus obtained by removing 

 the weeds without any cultivation. Valuing corn at 50 cts. a bushel, the esti- 

 mated damage sustained by an acre of corn from weeds alone amounted to 

 $20.44. 



Data showing the rainfall during the growing season for each year of the 

 test failed to establish any significant relationship between rainfall and the 

 amount of cultivation necessary. 



Recommendations regarding cultivation, the choice of varieties, and the fer- 

 tilization of the corn crop are discussed in a general manner. 



Corn variety tests, 1915 and 1916, L. W. Osborn (Arkansas Sta. Bui. ISO 

 (1917), pp. 3-31). — Corn variety tests at Fayetteville and at the ^lena and 

 Jlarianna substations, and numerous cooperative tests in different parts of the 

 State during 1915 and 1916 are reported, preliminary to a more complete report 

 of all corn experiments since 1003. The results of the tests of each year at 

 each experimental center are tabulated and briefly discussed. 



The moisture supply appears to be the limiting factor in corn production, the 

 relative standing of the varieties being closely related to their time of maturity. 

 Early and medium maturing varieties have led in practically all tests, unless 

 seasonal and soil conditions were exceptionally favorable. 



A study of the data relative to barren stalks indicates a close correlation 

 between moisture supply, as determined by the character of the soil and season, 

 and the percentage of such stalks produced. Early ami medium varieties, as 

 well as the more prolific sorts, showefl the lowest number of barren stalk.*!. 

 Surcropper, Hickory King. Biggs Seven-ear, Southern Beauty, Neal Paymaster, 

 Pool Prolific, White Wonder, I-«amlng, Reid Yellow Dent, and Diamond Joe 

 have contained a minimum of barren stJilks in three or more tests. 



Hybrids of Zea ramosa and Z. tunicata, G. N. Collins {V. S. Dcpt. Agr., 

 Jovr. Agr. Research, 9 {1917). No. 11. pp. S8S-S96. pis. 9).—Z. tunicata and 

 Z. ramosa are described, the nature of their variations from normal maize out- 

 lined, and a hybrid strain secured from a cross of the two made at Lanhara, 

 Md., in 1914 discus.sed in detail. The female parent was a plant of Z. ramosa, 

 while the male was a tunicate strain designated as half tunicate. 



Nine Fi plants of this cross were grown at Chula Vista, Cal., in 1915, of 

 which 4 were tunicate and 5 normal, indicating the heterozygous nature of the 

 half tunicate parent. The tunicate plants were all half tunicate and no trace of 

 ramosa characters were discernible. 



Fi plants were grown at Lanham in 1916 from 3 tunicate and 2 normal ears. 

 The 3 tunicate ears produced 326 mature plants and the 2 normal ears 82 plants. 

 The Fi progeny of the nontunicate or normal Fi plants showed segregation Into 

 normal and Z. ramosa types in the ratio of 3 : 1, the numbers being 65 normal 

 and 17 ramosa. No e\idence of tunicate characters was observed. 



The progeny of the tunicate plants, however, presented many intermediates 

 which have been divided into groups and discussed in detail. 



The author concludes that Z. ramosa and Z. tunicata should be regarded as 

 mutative reversions, the one recessive and the other dominant, as compared with 

 normal maize. The hybrid demonstrated that both behave as independent Men- 

 delian units. The Fi progeny was compo.sod of normal maize, showing none of 

 the characters of either mutation, the recurrence of both parental types In an 

 apparently pure form, and individuals combining the characters of both mutants. 

 In the last group normal expression was inhibited, resulting frequently in the 

 appearance of a totally different type of inflorescence, which was sterile and 

 abnormal to the extent that the tissue remained In an embryonic state, appear- 

 ing as a much-branched, white, succulent mass, similar to that described by 



