LEAKE AND RAM PRASAD 135 



The vegetative period has been defined as the period between 

 the date of sowing and the date of appearance of the first flower and 

 may be measured as the nmnber of days. This period is in itself 

 definite and also is determinable early in the season. It is, however, 

 subject to the influence of numerous subsidiary forces which make 

 the actual figure obtained for the plant merely the net result of the 

 action of these forces and not an exact measure of the true character. 

 Thus considerable seasonal variations have been found to occur. 

 These are indicated in Table XVI. A comparison between 

 the figures there given and the chmatic conditions for the years 

 concerned indicates that a delay in the arrival of the monsoon 

 leads to a considerable shortening of the vegetative period, but 

 that the period is also influenced by the strength of the monsoon 

 is indicated when the amount and frequency of the rainfall is con- 

 sidered. A strong and early monsoon with liberal rainfall leads 

 to vigorous vegetative growth and a delay in the flowering period ; 

 with a delayed monsoon the plants remain small and they flower 

 early. 



The difference which is induced in the length of the vegetative 

 period by these causes may amount to as much as a month or even 

 more ; and the introduction of a seasonal factor becomes necessary 

 .in any comparison between cultures of different seasons. 



Minor disturbances in the length of the vegetative period may 

 be produced by such causes as the failure of the earliest flower buds 

 to develop into mature flowers. The bud withers and falls, and the 

 true vegetative period is in such cases less than that actually 

 recorded. 



The inter-dependence between the type of branching and the 

 length of vegetative period may be indicated by a correlation 

 coefficient. Tabulating the figures obtained from a series of plants 

 derived from a cross between Type 3 and Type 4, of which the type 

 of branching has been determined, as above described, and of 

 which the length of the vegetative period has also been recorded 

 (Table XVll) the correlation coefficient is found to be -6628, while, 

 for a similar series, a correlation coefficient as much as '8589 has 

 been obtained. The inter-relation is, therefore, definite, and the two 



