WHEAT. 255 



"In most spring forms, however, the straws grow up from 

 the ground in a crowded, more or less compact, bundle, 

 spreading very little, and the adventitious root-system con- 

 sists of much thinner, less lignified roots closely contracted and 

 descending almost vertically with very little grip on the sur- 

 face soil ; plants with these root characters are very easily bent 

 to the ground as a whole, although the straw may be as strong 

 and rigid as that of the best winter varieties. " Lodging " of 

 this kind, which may even occur among isolated well-grown 

 plants, is due to weak root-hold; the straw being neither bent 

 nor broken."* 



Other factors also affect lodging. If sown too thickly, 

 insufficient light is accorded the plants and their etiolated 

 condition causes them to lodge badly ; high nitrogenous 

 manuring and over-irrigation also have much the same effect, 

 and certain diseases affecting the lower internodes weaken 

 these to such an extent that lodging of individual straws 

 results. 



(4) Shattering. — At maturity the grain is shattered out 

 more readily in some varieties than in others. The Kieti 

 variety shatters very badly and for this reason its cultivation 

 has diminished. 



(5) Stooling. — While not very important, the capacity to 

 stool as well as the manner of stooling varies considerably with 

 the varieties. To quote again from Percival's excellent mono- 

 graph :' " During autumn and spring, however, the primary 

 axis continues to grow very slowly, and, at the same time, in 

 the axils of its leaves buds are formed which expand into short 

 secondary stems; the latter also bear axillary buds, which are 

 capable of developing in a similar fashion into branches of the 

 third order, and so on. Thus, from the primary bud of a 

 single wheat grain, a large number of stems may be produced, 

 which remain very short until April [spring in South Africa] , 

 at which date they usually begin to expand, the strongest 

 of them ultimately growing out into straws, each with its 

 terminal ear. 



The production of these numerous shoots with unex- 

 panded internodes, which takes place near the surface of the 

 soil, is known as the ' stooling ' or ' tillering ' of the plant ; it 

 is the nominal process of branch-formation in the cereals 

 and grasses generallv." The extent of tillering is governed by 

 the variety — e.g., the late wheats tiller more than the early, 

 but may be modified by environment. Crowded plants tiller 



