?,u IV coM'KIikm;!': imki!N\ti(i\\i.i: hk (.KNininiK. 



Ili.'in il('i'|) cvrs. ()ii;iii li('ler(i/.\ tfous imlis idiuil IjhIIi l'orins ol' cyos niiiy Le 

 riiiiiid on ililTrrcnl liiliiTs, Ijiil llic sii|iiTliii;il vy is. un llic wliolc. llio duini- 

 niinl . 



Liik'ly a inoiisLrou.s l'urin ol' cye diu; lo fin onoinions ovcr f,To\\ lli of llic 

 " brow '" bas occurrcd in my cullure?. H ijivcs riso In a niislaUcn im])rossion 

 of " deplh ", but, as a malter of facl bas ocnrred so l'ar only in piiif /Irrl-ci/cd 

 families. ILis nol inberiled eilbcr sexiially or ascxually. 



Cohiir of Tuher. — Potalo plants bear tubors wbicli niay be IjlacU, i. p. 

 deep purplp, wbile, or red. Uie latlor Ijotii dark and pah\ Ail tliose types can 

 bc readily analysed and conform lo simple Mendelian laws wbcn used as 

 parents. Probably ail liibers wbatevcr tbeii- colonr, conLain a cliromog-en body. 

 Reb lubers, in addition, possess Iwo ollier raelf)rs. ])r()bably en/ynies. one of 

 wliicli inny Ix^ callcd /I, a reddening- l'aclor. and llic ollier l) a dcvel(i])ei- ol' 

 l'ii;ni(iil. 



Tbe following types liavelieen reeot^iiised : 



Reds of llie compDsilion l\r l)D or Ril Dd wliicb wben selled prodncc 

 families in wbich plants bearing red tubers are lo Ibose bearing wbile. as 7> : \. 



Redsof Lbc composition /?;• Dd whicli Avben selfed produee families in wîneb 

 plants bearing red tubers areto tbose bearing Avliite, as !l : 7. 



Purplesov blarl;i^ are due lo Ihe présence in addition lo /( and U of a fnrtlier 

 faclor P, and Ibe following types bave lieen isolatcd. 



Pnr|)les of Ihe composition PP Pili Dd whicb wben selfed jiroduce families 

 in Axliich Ihe individnals bearing pnrple tubers are lo Ihose bearing white 

 as :. : I. 



Purples of Ihc com]iosilion l'/i lir Dd whicb wlicn selfed produce families 

 in wliicli planis bearing Idack tulieis are l<i tbose bearing re<l ami ^vhileas 'il : 

 !l : iX. 



Purples of Ibe composition l'P Tir Dd whicb wben selfed produce families 

 in whicb plants bearing Idack tubers are to tbose l)earing white as '.I : 7. 



While lubered plants ail breed true wben selfed. However. wben Iwo 

 while-tubered planis of différent composition were maled logelher, Iben co- 

 loured tubers, red, black or botb, bave been oblained in appropriate mendelian 

 proportions. Tbe isolation of the varions possible types oHiv/iites is progressing. 

 One whicb, follow ing tbe notation I bave vcntured to use may be represented as 

 r r (? (/ bas been definitcly secured. 



Thesludyof fealures in the "' baulm '" such as foliage, bas been altempled, 

 but the difllculty of distinguisbing accuralely the varions types, prevents satis- 

 faclory analysis. Tbe discovery tbis year and Ihe definite isolation of strains 

 of polatoes wbich sprawl on the ground not being able to stand up is of parti- 

 cular interest. The condition of proneness is récessive and breeds perfectly 

 true. Tbe uprig/it condition is dominant, the stems growing boit uprigbl. The 

 hétérozygote wbich is also upright, is further characterised by being //«.<////. i. e, 

 tbe stem first begins lo liedown and Ihen after a short run of aljout 10 cm. on 

 tbe ground, tur'us up verlically and ail ils lower branches follow a siniilai' 

 course, giving Ihe plant a bush-like appeai-ance. 



In gênerai, growers bave selecled pui-e t/jiriijhh for Ihe markel, by 1 hâve 

 aiivady analysed some commercial varielies whicb are hetei'ozygous in Ibis 

 respect. In lai'ge field cullures of polatoes such as Flourbnil wbich is heler- 

 ozygons l'or jiinni'ni'ax nol a l'ew of Ihe ùiin/n/ planis show a distinct tendency to 



