216 Tmi^rovemenf in Indian Sngarcanes 



for it is felt that, until some control of flowering is obtained, working 

 along Mendelian lines is more or less out of the question. If the sup- 

 position of the Coimbatore ryots is correct, it would seem to indicate 

 that flowering ensues whenever the flow of sap is interfered with, whether 

 by the paucity of water or the unhealthiness of .the root system. 



Problem 3. Another matter which has attracted our attention is 

 that there appears to be a very close relation between richness and 

 purity of juice and vigour of growth. The first requisite in a seedling 

 cane is a high percentage of sucrose and purity of juice, but the total 

 quantity of sugar is what is aimed at in the field, and this will obviously 

 depend upon vigour of growth and the number and size of millable canes 

 in the crop. The first year's seedlings when analysed and weighed 

 showed a markedly converse relation between purity and vigour. The 

 smallest and most meagre plants had the richest juice and those seedlings 

 which were distinguished by the abnormal vigour of seedlings were 

 very poor indeed in sucrose content. Richness and purity, if dependent 

 on lack of vigour, may to all intents and purposes be regarded as a 

 diseased condition and, if so, must be very carefully distinguished from 

 purity and richness which are inherent and varietal. Among my 

 colleagues, Mr Parnell has drawn my attention to a similar relation in 

 indigo seedlings between meagre leaf production and richness in indigotin, 

 and Mr Anstead states that, in analyses made by him of individual 

 rubber trees in South Indian plantations, the latex richest in rubber was 

 obtained from poorly grown or stunted trees. 



Problem 4. One important line of work in the cane-breeding station 

 is the selection of suitable parents and inducing them to flower together. 

 But, even if we are successful in this, we are confronted with another 

 serious difficulty. How shall we determine if seedlings obtained are 

 really crosses? We can approach this problem either directly or 

 indirectly. In the first place we may actually cross the two varieties 

 with scientific precautions against self-fertilisation. This has been 

 successfully carried out in Barbados for several years. In Coimbatore 

 there are special difficulties in the way. The bulk of the canes arrow 

 during the heart of the north-east monsoon, a period of violent winds 

 and torrential rains. As the long stalk of the inflorescence (arrow) is 

 very easily damaged and the slightest bend appears to cause it to wither, 

 we have to erect over each arrow a gallows-like support, with a hanging 

 iron cage covered with muslin — much after the plan adopted in Java. 

 The difficulties in crossing such inflorescences can be readily imagined. 

 There are an enormous number of flowers on each arrow and the male 



