MINISTRY OF AfJllIOULTUKE, EGYPT. 



Bulletin No. IS. 



1 1 {i > r.vxicAi, SECTION.) 



THE SMUTS OF MILLET (Arwbvpogon Sorghum Jtmt.) , 



The Long Smut (Tolyposporiiem fil//cnii 



The Long Smut is the most common smut of millet in Egypt 

 and its occurrence c;in lie compared with that of loose smut of wheat. 

 It occurs in almost every cn>|> of millet throughout 1 he count rv. 

 but not in sutiicicnt quantity to cause an appreciable decrease in the 

 yield. This is part! v due to t lie fact t hat the number of heads at tacked 

 liardlv ever reaches as much as t \vo per cent, and partly because only 

 I he individual grains are attacked by the fungus. The number of 

 grains attacked in a single head may be anything from live to si 

 but. on an average about fifteen. 



When a grain is attacked it is replaced by a spore-sac which 

 measures ir>to:{| millimetres long by 4 to 5 millimetres broad. The di& 

 is conspicuous and easily recogni/able ( I'late 1, Fig. 1). The spore 

 splits longitudinally, starting at the tip usually, exposing eight to 

 ten dark brown filaments surrounded by a powder of the same colour. 

 The filaments are the isolated fibro- vascular bundles of the enlarged 

 ovary (I'late 1, Fig. 2). If a little of the powder is placed in wa let- 

 on a slide and examined microscopically it will be found to consist 

 of several spore balls which are composed of a number of closely 

 adhering spores (Plate I. Fig. 3). The individual spores are coverd 

 with warts on the free surfaces and smooth on the sides by which they 

 were attached to the other spores of the spore balls (Plate I. Fig. 4). 

 The spores are brown, round, but somewhat flattened on the smooth 

 sides and measure 10 to 1 ."> 11. in diameter. They germinate readily in 

 a one per cent solution of cane sugar and normally produce a tlr 

 celled thread (promycelium). Each of the cells of the promyceliutn 

 t hen gi\ i its tip. or laterally near the septa, to small unicellular 



structures called sporidia (I'late I, Fig. 5). The spores on germination 

 also produce septate germ tubes which then give rise to sporidia. 

 Sporidia which have become detached from the cells of the promyceliutu 

 give rise to secondary sporidia. 



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