I'l.AXT brei:ding 1437 



1072 -Experiments on Crossing Two Varieties of Sunflower {Helianthus annuus 

 X // agrophyllus A. Gray) to obtain a type resistant to rust, in Russia. — 



Sazvperov, F. A., in Tpi/(Jhi 'liHijio 110 iipiiir.nidHoii 'fioiiUiHiihih. (Hiilktin of Applied 

 Botany). Year IX, No. 5. (90) pp. 207-227; (luiiili^h text pp. 228-24.}), i platc-s. 

 Petrograd, >Iay 191 6. 



• In the breeding of sunflowers for oil great importance is attached to 

 their resistance to several hostile agents, ut which the chief are Homeosoma 

 nebulella Hb., Orohanche cumana Wall., and Pnccinia Helianthi Schr. 

 There are t^-pes of vSunflower which are resistant to the first or second 

 enenn- (for example the group of " cuirassed " (i) Sunflowers, and among 

 them the Karzinskii, which is not attacked hy Homeosoma nebulella Hh.. 

 and the Zelcnka which, besides, resists Orohanche cumana Wall), but 

 we do not yet possess an oil Sunflower capable of resisting the rust, the most 

 redoubtable enemy of all. Puccinia Helianthi attacks all types, that of 

 H. annuus I,, as well as that of H. dehitis Nutt ; H. agrophyllus A. Gray, 

 an ornamental plant, is a solitar}^ exception. 



The experiments were carried out at the section of \'oronezh of the 

 Bureau of Applied Botany of the Ministry of Agriculture. The preliminary 

 investigations carried out by the author on several varieties of sunflower 

 had established the fact that H. Agrophyllus A. Gray, was endowed with 

 a certain resistance to rust ; in 1912, one plant of this was not attacked by 

 rust, and in 1913. a vers* v/et j-ear, a good number of plants escaped the 

 disease. For this reason, a cross was made between (1) a variety of cuiras- 

 sed Sunflower (var. t'golnij) resistant to Homeosoma nebulella and to Oro- 

 hanche cumana Wall and selected from one of the plots of sunflowers not 

 infested by Orohanche, and (2) a H. agrophyllus received from Germany. 

 The choice fell upon the latter because, unlike other seeds obtained from 

 Italy and IMcscow, it was not attacked by rust. 



The mother plant was H. annuus and the male plant H. agrophyllus ; 

 their characteristics are as follows : 



Helianthus Atuiuus L,. var. Ui^olinij. Helianthus Agrophyllus A. Gra3^ 



i) Stem not branched Stem much branched from the base. 



2) Average height of stem 165 cm ( = 66 ins.). Average height of stem, 175 cm (= 70 in?.). 



3) Stem covered with thick and rigid hairs. Stem covered with soft whitish hairs. 



■l) ^'pper part of the stem clothed with Ion- Ipper part oi the stem clothed with a thick 

 ger and softer hairs. down of a silvery white colour. 



5) Middle leaves heart-shaped. Middle and especially upper leaves elonga- 



ted, or lanceolate. 



6) lycaves green and wrinkled I^eaves whitish, fclty on both sides, and soft 



7) A single large inflorescence. Several small inflorescences the largest niea 



sures 7-8 cms (— 2.8-3.2 ins.) 



8) Receptacle flat, slightly convex. Receptacle vtrj' convtx. 



q) Ray florets yellow (var. flams). Kay florets dark yellow (var. vikllinus). 



10) Disc florets dark yellow (var. vitdlinus) Disc florets brown (var. brunnms). 



(1) The " cuinissed " sunflower'^ distinguished by a special structure of their fruit (a- 

 chene) in the pericarp of which, between the corky la>er and that of sclereuchyma there occurs 

 a -iii'.cially thickened layer. 



