20 VARIETAL CHARACTERS OF INDIAN WHEATS. 
Indian wheats which were resistant being Emmer' (7. dicoccum 
Schrk.) In 1906 and 1908 the amount of rust at Lyallpur was 
slight. Further detailed observations are necessary to work out 
the relations between the Punjab wheats and the rusts which 
attack them and the work is now possible as the types have been 
isolated and grown in prre culture. As in other characters, 
observations on rust resistance are of no value when the 
plots are mixtures of many different kinds. Some of the Punjab 
types have been grown at Pusa when most of them were severely 
attacked by brown rust (Puccinia triticina Eriks.). Both at Pusa 
and Lyallpur we observed great differences in the amount of rust 
on the same variety when sown on slightly different soils. At 
Pusa, there is as a rule much more rust when the soil moisture 
is liable to give out, than there is on the heavier moisture retain- 
ing soils. The degree of susceptibility of the various kinds to the 
three Indian rusts is of importance in plant breeding as Biffen’ has 
found in England that immunity to yellow rust is a recessive 
character. 
8. STRUCTURE OF THE EAR. 
(a) The form or shape of the ear—The shape of the ear of the 
common wheats of the plains of India does not exhibit the same 
range as in Kurope, and it is not possible to utilise this character 
to the same extent as has been done at the Svaléf* Experiment 
Station in Sweden. 
(b) Density of the Ear.—The density of the spikelets on the rachis 
has been used by many observers as a character for differentiating 
the various kinds. Wheats are often referred to as lax, medium 
or dense according to the distance between the spikelets. These 
terms, however, are not very definite, and we have followed von 
| Howard, A. & G. L. C., Jowr. Agr. Science, Vol. 11, 1907, p. 278. 
2 Biffen, R. H., Jour. of Agr. Science, Vol. U1, 1907, p. 109, 
3 Fruwirth, |. ¢. 
