INSTITUTE AND COLLEGE, PUSA, FOR 1913-14. 37 



able that these latter results can be explained by the work 

 of Kidd (Proc. Roy. Soc, B, Vol. 87, 1914) who has shown 

 that the decay of green manure produces so much carbon 

 dioxide in the soil as to inhibit the germination of seeds. 

 Until a certain stage is reached in the decay of a crop like 

 sanai, it is quite possible that want of oxygen and excess of 

 carbon dioxide would be limiting factors to a rapidly grow- 

 ing crop like tobacco. That a poor germination is obtained 

 if seeds are sown soon after a green crop of sanai is 

 ploughed in, w T as observed twice during the past year at 

 Pusa, once in the case of Java indigo and once in the case 

 of tobacco sown in a nursery which had been recently green 

 manured with sanai. The absence of any marked crop 

 increase on the heavy lands in Bihar, following a dressing 

 of seeth, and also the poor crops obtained on such lands 

 after sanai ploughed in (especially in wet years or when the 

 soil is waterlogged by flooding) are probably also connected 

 with oxygen supply. Kidd's researches are likely to prove 

 of considerable interest to India. 



A paper is in preparation, by the Personal Assistant, on 

 the inheritance of characters in Nicotiana rustica. L., 

 the observations on which were brought to a conclusion 

 during the year. 



Gram. — The selection work on this crop was continued 

 and three of the most promising types, including the high 

 yielding white gram which was valued so highly at Bombay 

 in 1912, have been distributed for trial on estates in Bihar 

 and also in other tracts of India. A certain amount of 

 natural crossing takes place in this crop, the extent of which 

 under Bihar conditions is now being investigated. 



Fibres. — The work on the inheritance of characters in 

 Hibiscus Sabdariffa was continued, but it was not found 

 possible to complete this investigation during the year. The 

 work is being continued. 



The behaviour of some of the cultures of sanai (C rota- 

 toria juncea) at Pusa indicated that extensive natural cross- 

 ing takes place in this crop when two or more varieties are 

 grown next to next. The pollination mechanism in the 



