6 Department Circular 26^, U. S. Dept. of Agriculture. 



second frost test none survived, although 12.5 per cent of the phmts 

 in the rows of Bkie Blossom Dutch, Saginaw, and two other flaxes 

 survived. The first two spring tests in which the same varieties and 

 selections were duplicated confirmed these results, and it is concluded 

 that the frost resistance varies with different flaxes and that these 

 differences are sufficiently marked to warrant further selection for 

 increased resistance. In Table 2 the flaxes are arranged in accordance 

 with their rank in frost resistance. At the top of the list is selection 

 No. 21003, followed bv Blue Blossom Dutch, a short commercial 



/A 



2^ 



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/OR. 



/^% 



SR,\ 



30%. 



Fig. 3. — Diagram showing the improvement secured by selecting for increased frost 

 resistance. Saginaw, a tall fiber-flax selection, is several times as resistant as White 

 Blossom Dutch. A reselection from Fiber Investigations No. 21003 is 3 times as 

 resistant as Blue Blossom Dutch and 15 times as resistant as \Mute Blossom Dutch. 

 The percentages of plants that survived frost are specified. 1, White Blossom Dutch, 

 a commercial fiber flax : 2, Blue Blossom Dutch, a commercial fiber flax : 5, Saginaw, 

 a tall fiber-flax selection : 5R. Reselection from Sasinaw. No. 1805-21 ; 10, Selection 

 21010, a tall flber-flax selection; lOR. Reselection ifrom 21010: 3, Selection 21003, a 

 t^ll fiber-flax selection ; 3R, Reselection from 21003, No. 2203-18. 



fiber flax. Xorth Dakota Resistant Xo. 114. Saginaw, and selection 

 Xo. 21014 follow directly behind and almost in the same class as 

 Blue Blossom Dutch. The percentages of survivals tally very well 

 for the most part, so that the order or rank in resistance would not 

 change very much, even though the data from only one frost test 

 were to be used. AVliile it is not safe to generalize on the relation 

 between frost resistance and flax wilt from observations on only 

 15 kinds of flax, it is evident that as a rule the flaxes that are most 

 resistant to frost are also strongly resistant to flax wilt. Out of the 

 eight flaxes most resistant to frost, all except one are strongly re- 

 sistant to wilt, and out of the seven flaxes most susceptible to frost, 

 only one is strongl}^ resistant to wilt and one parth' resistant to wilt. 



