272 Male- Sterility In Flax 



Whether it should be discarded as an error or not we cannot yet say. 

 It came in a family containing only two plants, the other being a male- 

 sterile. 



From the evidence of these 26 plants we must conclude that the 

 fibre-flaxes in general, perhaps always, are heterozygous in respect of 

 the male-sterile allelomorph, and that in segregation this allelomorph is 

 relegated to the male side. 



As regards oil-flaxes we have only preliminary indications and can 

 make no statement as yet. 



The procumbent itself is clearly hermaphrodite in genetical com- 

 position on both male and female sides. The male side was tested as 

 follows. Tall X procumbent (Expt. 3) gave from 3 F^ plants 559 all ^ in 

 F2 ; white X procumbent similarly gave 157 5 in F^ (Expt. 4) ; also 

 male-steriles fertilised by procumbents (3) gave 101 5 , and also 2 male- 

 steriles (Expt. 5) which may safely be assumed to have arisen by self- 

 fertilisation, the mother-plant not having been emasculated. 



But when the procumbent is used as mother and fertilised with 

 pollen from a fibre-flax, F^ is a normal hermaphrodite, and in F2 the 

 male-steriles appear as 1 in 4. It is proved therefore that the female 

 side of the procumbent must in some way be different in constitution 

 from the female side of the ordinary flaxes. In heterozygosis with the 

 female of the procumbent the dominant factor for anther-development 

 passes with its negative allelomorph to both male and female organs of 

 the offspring, thus producing an ordinary Mendelian result, but when 

 the same negative is in heterozygosis with the female side of the 

 common flax, it passes wholly to the pollen, evidently segregating not 

 later than the constitution of the sexual organs. The ordinary flax, 

 though heterozygous, is thus able to breed true just as Begonia Davisii 

 does for singleness (though heterozygous for doubleness) and as the 

 various Oenotheras investigated by Renner may do, though heterozygous 

 for several complexes. 



In connexion with this example the somewhat cognate evidence 

 discovered by Miss Pellew in Campanula carpatica should be recalled. 

 There also very similar plants were shown to possess distinct types of 

 segregation in respect of the same negative allelomorph. The case of the 

 flaxes differs from that of the Gampanida, for in that example the plants 

 in which both allelomorphs went to both sexual sides showed an 

 irregular distribution, whereas here they follow a normal Mendelian 

 system. It will be interesting to see whether a cytological basis for 

 these phenomena can be detected. 



