Richey: Use of Greenhouse in Corn Breeding 



393 



at elevations of 10,000 to 11,000 feet, 

 where light frosts are experienced ; but 

 it is not to be anticipated that the 

 Andes berry will succeed in parts of the 

 United States which are too cold for 

 the loganberry. More probably its 

 cultivation will be limited in this 

 country to the Pacific Coast states, 



Arizona, New Mexico, and parts of 

 Texas. Particular attention may be 

 directed to its value for plant breeders: 

 because of its vigor, and the large size 

 and good quality of its fruit, it seems 

 likely to prove an excellent subject 

 for crossing with some of our northern 

 raspberries. 



THE USE OF THE GREENHOUSE IN 

 CORN BREEDING 



Frederick D. Richey 



Agronomist in Corn Investigations, Office of Cereal Investigations, Bureau of Plant 

 Industry, U. S. Department of Agriculture 



THE improvement of corn by selec- 

 tion within self-fertilized lines 

 necessarily is a slow process, and 

 any method that will shorten the time 

 required is highly desirable. It has 

 been shown that sweet corn is adapted 

 for forcing under glass. ^ The green- 

 house also has been used successfully in 

 inheritance studies with corn as shown 

 by casual reference in several articles. 

 The author is informed by Mr. G. N. 

 Collins, however, that attempts to grow 

 corn during the winter — that is, planted 

 in the fall — in the greenhouse have not 

 been successful. The plants under 

 such conditions have failed to develop 

 normally and have ripened prematurely 

 with a scanty production of seed. The 

 following notes indicate that under 

 some conditions such practice is en- 

 tirely successful. The determining 

 differences are not known, and these 

 notes are offered to indicate the prac- 

 ticability of this method, with the hope 

 that interest in the possibilities of 

 greenhouse culture may be promoted. 



USE OF THE GREENHOUSE 



The crop was grown in one of the 

 department greenhouses at the Arling- 

 ton Farm, Rosslyn, Virginia, during 

 the winter of 1920-21. The center 

 space was excavated to a depth of 12 

 inches and filled with good soil. Under 

 greenhouse conditions the secondary 

 roots of corn frequently originate 



abnormally near, and in extreme cases 

 even above, the soil surface. To 

 nullify the effect of this tendency the 

 seed was planted in the bottom of a 

 6-inch furrow which was not filled in 

 until the root system had become well 

 established. This method proved very 

 effective. 



After emergence the plants were 

 thinned to a stand that provided 1.67 

 square feet per plant. This is at the 

 rate of over 25,000 plants per acre, 

 and was entirely too thick, as, although 

 there was plenty of moisture and fer- 

 tility, it interfered with proper light 

 distribution. It is thought that a rate 

 allowing three square feet per plant 

 would utilize the space to good advan- 

 tage. 



The following strains were grown: 

 8 plants of Gerrick that had been self- 

 fertilized for five generations; 24 plants 

 of a Chinese dent variety, self-fertilized 

 for one generation; and 20 plants of a 

 chlorophyll-deficient, brachytic strain 

 of U. S. Selection No. 201 that had been 

 self-fertilized for three generations. 

 Two ears were obtained from the 

 Gerrick, none from the No. 201, and a 

 few seeds on each of three cobs from the 

 Chinese variety. 



There also were 116 plants froni 58 

 Fi crosses between self-fertilized 

 strains of U. S. Selection No. 201. 

 The following notes refer to these cross- 

 bred plants. 



' Rane. F. W. Green Corn Under Glass. N. H. Agr. Expt. Sta. Bull. 60. 1899. 



