198 Sterile ''Dwarfs'' in Hiimuliis Lupuliis L. 



In a "cross" (Ref. no. 5/07) made in 1907 the female hop was the 

 variety known as Fuggles^ and the male hop (Ref. no. M8) one of the 

 English forms with a red-bine. 51 hops containing 256 seeds were 

 obtained from the pollinated flowers ; while the 44 " control " hops 

 contained no seeds^ 87 seedlings were raised, of which 52 proved to 

 be climbers and fertile ^ and 35 proved to be "dwarfs" and sterile. 

 Prof Bateson has pointed out to me that here the ratio of " dwarfs " 

 to " climbers " approximates to 7:9. 



In a second cross (Ref no. 4/07) made at the same time, between 

 the same female variety (Fuggles) — though different individuals'* were 

 used from those in the first cross — and a certain male hop (Ref no. G 27), 

 one of the English forms with a green-bine, 99 hops containing 285 seeds 

 were obtained from the pollinated flowers, and 28 hops, all without 

 seeds, from the " control " branches. 67 seedlings were raised, of which 

 66 plants proved to be climbers and fertile % and 1 plant a dwarf and . 

 sterile. If we assume that this single dwarf was due to the fertilisation 

 of a flower by a strange pollen-grain during the time the bag was 

 removed'', and if we also assume that the female plant in these two 

 "crosses" was identical in character ^ then it appears that the latent 

 characters of dwarfness and sterility are carried by some English forms 

 of the male hop and not by others. However this may be, it is quite 

 certain that the proportion of "dwarfs" to climbers (if dwarfs really 

 occurred at all) in this second ." cross " was altogether different from 

 that obtaining in the first "cross." 



In a third "cross" (Ref no. 1/09) made in 1909, the female hop was 

 the German variety " Stirn " and the male hop one of the English forms 

 with a bine striped with red and green (Ref no. Z 12). The pollinated 



* Prof. Percival {Journ. Boyal Agric. Soc. England, lxii. p. 87 (1901)), writing of the 

 origin of this variety, says, " The original plant was a casual seedling which appeared in 

 the flower-garden of Mr George Stace, of Horsmonden, Kent. The seed from which the 

 plant arose was shaken out along with crumbs from the hop-picking dinner-basket used by 

 Mrs Stace, the seedling being noticed about the year 1861. The ' sets' were afterwards 

 introduced to the public by Mr Kichard Fuggle of Brenchley, about the year 1875." 



2 The controls, it. should be noted, were imperfect in that the bags covering them were 

 not removed at the time when this was done to the branches that were pollinated. 



3 31 were ? , 4 were s , and 17 were killed by eelworm before they flowered. 



* The commercial cultivation of the hop being entirely vegetative, by means of sets or 

 cuts — the thickened basal portion of the stem — it might be assumed that all individuals of 

 any variety are identical ; it is very probable, however, that the stocks of some varieties 

 have not been kept true. 



^ 57 were ? , 7 were d" , 1 was monoecious, and 1 was killed by eehvorm before it 

 flowered. 



" See footnote 2 above. 



