56 SCIENTIFIC REPORTS OF THE AGRICULTURAL RESEARCH 



root which ultimately shows a tendency to turn upwards. 

 Further observations, however, appear to show that this is 

 an effect of the chlorosis,- and not a cause. As the water- 

 level rises and the soil becomes practically waterlogged to 

 very near the surface in the rains, as in East Bengal, the 

 healthy, well-nourished plants throw out more and more 

 surface roots, till ultimately a bunch of surface roots is 

 found close to the surface. The chlorotic plants, on the 

 other hand, being enfeebled through their inability to syn- 

 thesise carbohydrate, are unable to do this, and in conse- 

 quence, in addition to being starved from above, are slowly 

 asphyxiated from below. Finally, the tap root of such 

 plants endeavours to turn upwards, away from the wet. A 

 systematic examination of the roots is in progress with a 

 view to determine this. 



Cultures grown at Pusa seem to show that the chlorosis 

 is undoubtedly hereditary, seedlings of a few days old show- 

 ing signs of it. The main facts so far proved are : — 



1. Chlorotic plants never breed pure, but always throw 



greens. 



2. Green plants may (as opposed to chlorotic) breed 



practically pure, but generally throw chlorotics. 



.3. The percentage of chlorotics (whatever the parent is, 



green or chlorotic) is not constant. In the 



' variety Kahya Bomoai, in 1919, out of 42 plots, 



the percentage varied from 11 to 30, with an 



average of 21-5: 



4. By constantly selecting chlorotics and breeding from 

 these, a race of practically pure chlorotics can 

 be produced, and by constantly selecting greens, 

 a race of practically pure greens can be pro- 

 duced, but no absolutely pure race of either has 

 yet been obtained. In chlorotic plots a few 

 greens always appear, and in green plots a few 

 chlorotics. 



The facts tend to show that it is possibly a case of 

 maternal inheritance, the disease being passed on through 

 the cytoplasm of the egg-cell. This cannot be definitely 



