191 7. j The Fourth Indian Science Congress. clvii 



equally important results, the presence of starch grains inside the cells 

 of the style branches appearing to be an indication of female fertility. 

 It is hoped that the above studies will introduce a certain amount of 

 certainty in future selling and crossing operations. 



Bagging is found to have an inhibitory effect on the seed setting in 

 an arrow, chiefly in the case of the thick cane3, and a study of tempera- 

 ture conditions inside and outside the bags shows a higher temperature 

 under the former conditions, occasionally by as much as 10 degrees at 

 midday. 



Because of the poor and comparatively slow results obtained in other 

 countries by actual emasculation and cross pollination, this method was 

 found to be unsuited for purposes of the station, which was sanctioned only 

 tor 5 years, and new methods had to be evolved. 



J Study of the Sucrose Variations in successive Cane Joints as 

 they attain maturity, with special reference to the Death 

 of the Leaves. — By T. S. Vknkatraman and K. Krishna- 

 murthy Rao. 



The main work at the Sugarcane Breeding Station, Coimbatore, is to 

 raise a large number of sugarcane seedlings year after year, grow them to 

 maturity and select the best of these, as regards their botanical, agricul- 

 tural and chemical characters, for propagation. 



The sucrose value of any seedling is ordinarily ascertainable only 

 when the seedling is ripe and is harvested. As this takes sometimes as 

 long as 20 months from the date of germination, an attempt was made to 

 get some earlier indication of it. Besides this, it would save heavy 

 botanical and chemical work on undesirable seedlings to be able to detect 

 the good ones before maturity. 



(1) An analysis of that part of an obviously immature cane which 

 bears only dead leaves (analysis up to dead leaf) showed that this part 

 of the cane is, in a certain sense, mature ; but the interference of various 

 other factors (such as shooting, lodging, weather conditions) prevented 

 this form of analysis from being fully useful. 



By comparing the analyses, however, of the same, cane* up to the 

 highest dead leaf (Dead leaf analysis) and up to the point where the ryot 

 ordinarily cuts the cane for the mill (Ryots' sample analysis), it was found 

 that, whereas the two figures show verv great differences when the canes 

 are immature, they practically coincide at the time of maturity. Here 

 then we have a new method of ascertaining the maturity of a cane. 



(2) By cutting the canes into successive pieces from the base upwards, 

 and analysing these separately, a better result was obtained. 



(a) In a very immature cane the highest sucrose content wa 



found in the lowest section. 



(b) As the cane ripens this region of highest sucrose content 



gradually moves upwards. 



(c) If different canes of the same variety are sectionally analysed 



on different dates, the highest sucrose contents obtained 

 on those dates are practically identical. 



(d) A cane left growing in the ground after it has attained 



maturity showed rapid deterioration in the basal joints. 



The highest sucrose reading obtained by sectional analyses we have 

 called the ' Sucrose Index 7 of the cane, and it is claimed that this is fairly 

 constant, and will enable a comparison to be made between different 

 s eedlings even when they are immature. 



1 This paper will be published in extenso in the Congress number of 

 the Agricultural Journal of India. 



