Standardization of light regime to optimize growth and yield of spray chrysanthemum for winter under sub-tropical conditions.

The photoperiodic regime in relation to optimize growth and yield of spray chrysanthemum var. Punch was studied during 2011–13. The growth parameters such as plant height, total leaf area per plant at peak vegetative, bud appearance and flowering stage, internodal length and yield attributed characters differed significantly for continuous and interrupted light regime. With respect to growth parameters, 10 min of continuous light in every 30 min cycle for 8 h + 13 h dark (L6S1) recorded the highest plant height (126.54 cm) and total leaf area per plant (1106.33 cm2) at flowering stage which in turn reflected on yield. The yield attributed characters such as optimum days taken to first flower bud appearance (50.16), days to first harvest (95.47) and cut stem yield (78.65 stems/m2) are also registered high in L6S1.