PLANT GROWTH ANALYSIS OF GREENHOUSE CHRYSANTHEMUM ON INTERRUPTED PHOTOPERIODIC REGIME

S. GANESH¹*, M. KANNAN², M. JAWAHARLAL³, R. ARULMOZHIYAN^4
1Department of Floriculture & Landscaping, TNAU, Coimbatore, 641 003
²Department of Floriculture & Landscaping, TNAU, Coimbatore, 641 003
³Horticultural College & Research Institute for Women, TNAU, Tiruchirapalli, 620 009
⁴Agricultural College & Research Institute, TNAU, Tiruchirapalli, 620 009
* Corresponding Author : ganes4u@gmail.com

Received : 18-03-2016     Accepted : 15-04-2016     Published : 07-07-2016
Volume : 8     Issue : 23       Pages : 1470 - 1473
Int J Agr Sci 8.23 (2016):1470-1473

Keywords : Greenhouse chrysanthemum, interrupted light regime, plant growth analysis, crop growth rate, net assimilation rate, IAA oxidase activity, flower yield
Academic Editor : Attri B. L., Singh Anshuman
Conflict of Interest : None declared
Acknowledgements/Funding : None declared
Author Contribution : None declared

Chrysanthemum is the significant cut flower in the Indian market. It is a short day plant where flowering occurs when existence of long nights and short days. A greenhouse study was conducted to find out the physiological response of chrysanthemum due to interrupted photoperiodic regime at a Private garden Salem Green Plants Limited, Yercaud, Salem District in Tamil Nadu. The study was carried through in a Factorial Randomized Block Design (FRBD) with 21 treatment combinations and three replications. The first factor (L) comprised of seven long day regimes (3h, 4h & 5h extended light along with 6h, 8h & 10 h interrupted LD regime) including control and three levels of SD regimes (13 h, 14 h & 15 h dark) constituted the second factor (S). The results revealed that 10 min of continuous light in every 30 min cycle for 8 h (4 h extended light) along with 13 h short day regime (L6S1) had improved the plant growth parameters like crop growth rate (CGR), net assimilation rate (NAR), relative growth rate (RGR) and IAA oxidase activity at the critical stages of the crop (66.34, 186.31 and 166.07 µg of un-oxidized auxin g-1 h-1). This is followed by L3S1 (4 hours of extended light continuously) which registered the lowest level of auxin content at vegetative stage and higher amount at bud appearance and flowering stage respectively. Total carbohydrate content was highest (L6S1) at bud appearance stage of about 3.35 % followed by plant receiving interrupted lighting for 8 hours duration. The improvement in physiological parameters influenced the number of quality grade flowers (73.90 stems/m2) and cut stem yield (78.60 stems/m2).