40 BULLETIN 33, U. S. DEPARTMENT OF AGRICULTURE. 



included in the regular varietal trial. All varieties are continued in 

 the nursery at least three years before being- discarded. 



PURE-LINE SELECTIONS. 



Pure-line selections have been made of several unpedigreed cereal 

 varieties, which have proved well adapted to the conditions at 

 Dickinson. Typical and sometimes unusual heads of the variety are 

 selected in the field. The length of these heads and the number of 

 kernels each contains are usually determined and the heads photo- 

 graphed. Twenty kernels from each head are planted in rows 5 

 feet long and 12 inches apart. The kernels are placed 3 inches 

 apart in the row. Notes are taken throughout the growing season 

 upon the comparative behavior of the different selections. Each 

 row is harvested and thrashed separately, and the seed is used the 

 following year for planting in the pure-line selection nursery, where 

 they are more carefully studied and tested for yield. The pure-line 

 selection nursery is similar to the varietal nursery, the rows being 

 17 feet long and 12 inches apart. Equal weighed quantities of seed 

 are sown in each row. Notes similar to those taken on the varieties 

 are taken on the pure lines. Check rows sown with the unselected 

 parent variety are used, and any improvement which is made is thus 

 easily determined. This nursery is continued from year to jeav. 

 All pure lines are usually grown three years before any are discarded. 

 The highest yielding strains are then planted in larger plats of any 

 convenient size, to increase the seed. Finally those pure strains that 

 have proved superior to the parent, as well as to other pure lines, 

 are introduced into the plat varietal trials. 



From such a large number of selections as there are at Dickinson a 

 great mass of data has naturally been accumulated. The limits of 

 this bulletin prevent its presentation here. As previously mentioned, 

 a strain of Kubanka durum wheat, Kubanka No. 8 (C. I. No. 4063), 

 and a strain of Early Mountain oats, Early Mountain No. 2 (C. I. 

 No. 656), have been developed which have proved superior to the 

 original varieties. In Table XXI some of the results obtained in 

 1913 in improving the yield and the milling and baking qualities of 

 Ghirka wheat are shown. This table shows the possibilities of im- 

 provement and also the possible increase or decrease in quality and 

 yield of grain that may be obtained from pure-line selections. 



