1Dr. A.S. College of Agricultural Engineering, M.P.K. V., Rahuri Pin - 413722. Distt. Ahamed Nagar, M.S.
Centre of Advanced Studies in Agricultural Meteorology, College of Agriculture Campus, Shivajinagar, Pune-411005, (M.S.)
Fhotoperiod is one of the most important factor which controls the basic vegetative phase (BVP) of crops. The present experiment was conducted to determine juvenile stage of sorghum genotypes and thereby to determine the thermal time (TT) for juvenile stage of sorghum. Five sorghum genotypes were grown under 10.0 h and 16.0 h photoperiods. Plants were shifted daily from inductive 16.0 h to non-inductive 10.0 h photoperiod and vice versa, from the day of emergence till start of panicle initiation (PI). The plants were found to be insensitive to photoperiod in early growth period i.e. upto 14–21 day after emergence. This was identified as juvenile stage of sorghum. The thermal time for this stage ranged between 243±4.24 to 360±4.24. The average length of inductive stage was 8.8±0.54 and 15.4±1.45 d for non-inductive 10.0 h and inductive 16.0 h photoperiod respectively for the genotypes under study.
