PLANT BREEDING 



ALFALFA 



In the alfalfa breeding work live series of plots are now under 

 test. One of these is located within the covered garden on the 

 University grounds, at Tucson, and the other four on the experi- 

 mental farm near Mesa. In the series at Tucson a large number 

 of individual plants are being tested as mother plants. Each indi- 

 vidual is cut as soon as it comes into maturity, (early blooming 

 stage), and weighed. By this means it is hoped to tind high yield- 

 ing strains having the power of rapid growth and quick recovery 

 after cutting. In the 121 days, from August 20th to December 1st, 

 a number of plants matured three cuttings, whereas, others ma- 

 tured only one. The majority of the plants matured two cuttings, 

 the first being made about September 20th and the second about 

 October 25th to November 10th. 



A strain of alfalfa ( Xo. 17) originating from a single plant 

 selection in 1909 has been maintained and increased on account of 

 the good yield and high quality of hay produced by it. Apparently, 

 however, the mother plant was a hybrid, for the offspring was by 

 no means uniform in type. It was decided therefore to make 

 pedigree selections within this strain. Seeds from 25 selected mother 

 plants were therefore secured and sown in plant rows at the Mesa 

 Farm. The differences in average 3rield per plant for these rows 

 are so interesting that they are given in Table X. in the order in 

 vhich they occurred in the field. 



Rows Nos. 444 and 462 may be noted for their high yields. 

 whereas, rows Nos. 447 and 461 are correspondingly low in yield. 



Yields for the 18 one-fourth-acre plots at the Mesa Farm which 

 were planted in the fall of 1916 were recorded during the present- 

 crop season. Table XI. gives a summary of the results. 



In the fall of 1917, 36 pedigree races in rows, each 600 feet 

 long, were planted on the Salt River Valley Farm. This series con- 

 stitutes the second elimination test of a large number of plant rows 

 previously tested on the trial grounds at Tucson. In addition to 

 these a series of 22 one-eleventh-acre plots were planted on the Salt 

 River Farm. These plantings constitute a series of increase plots 

 for testing out on a larger scale the elite pedigree races which have 

 already withstood a first and second eliminati'm test in rows. 



