PLANT BREEDING 



W. E. Bryan, E. H. Pressley 



ALFALFA 



Pure-line studies with alfalfa have been continued as out- 

 lined in the Thirtieth Annual Report of the Arizona Agricul- 

 tural Experiment Station. Owing to the cost of individual plant 

 cages, funds were available for the construction of only fifty. 

 Since this number of cages limited the pure-line studies to a 

 single variety, the Hairy Peruvian was chosen for the past sea- 

 son's work. This is one of the most important varieties of al- 

 falfa in the State. Notes were taken during the early blooming 

 stage on each of the caged plants as follows : 

 Stems : Size, color, upright or reclining, height, and extent of 



branching. 

 Leaves : Size, hairiness, and extent of leafiness. 

 Flowers : Number of open clusters, color and distribution. 



The cages were placed over the plants on May 15, 1921, 

 care being taken to remove the flowers which had already 

 opened. By June 4, a large number of flowers had appeared 

 on several of the plants; the cages were then removed from 

 the plants, and the flowers of each plant were hand pollinated 

 (selfed) by rolling each flower cluster between the thumb and 

 fingers. The cages were immediately replaced after each plant 

 was pollinated and the hands of the person were dipped in a 

 solution of mercury bichloride, 1 to 1000, and thoroughly dried 

 before beginning with the next plant. From observations made 

 on the amount of seed set on the plants under the cages, as 

 compared with that set on uncaged plants, it is evident that 

 caging interferes to some extent with seed setting. However, 

 there is considerable difference between the amounts of seed 

 set on different plants under the cages. 



COTTON 



There is a distinct need in Arizona for a premium staple 

 upland cotton which will mature a profitable crop in those re- 

 gions which have a growing season too short for the American- 

 Egyptian cotton. A cotton breeding project was therefore 

 planned and begun in the spring of 1921 for the purpose of 

 breeding up such a cotton. As foundation stock for this work 



