Effect of CPPU Brassinolide and Prohexadione calcium on photosynthesis, transpiration rate and related parameters in new castle apricot

Abstract

Apricot, although being the third most important stone fruit crops of India, still requires a great improvisation from production point of view. Growth regulators are being used by the growers to increase the yield by improving the yield attribute parameters. Positive impact of growth regulators on net photosynthetic rate and related parameters leads to better yield and quality of fruits. Keeping this in forefront, a study entitled “Effect of CPPU Brassinolide and Prohexadione calcium on photosynthesis, transpiration rate and related parameters in New Castle apricot” was carried out at Dr. Yashwant Singh Parmar University of Horticulture and Forestry, Nauni with the objective of improvising the physiological parameters and thereby, increasing the yield. The study was conducted on twenty three-year-old experimental trees which were subjected to 10 treatments viz. CPPU at 2.5, 5 and 10 ppm applied at petal fall, prohexadione-calcium at 50, 100 and 200 ppm at pit hardening stage and brassinolide at 0.5, 1 and 2 ppm at petal fall. The results of the study showed that the treatment T6 (200 ppm Pro-Ca) had the higher stomatal conductance (18.2 mmol m-2 s-1), transpiration rate (22 mmol m-2 s-1), net photosynthetic rate (52.1 mmol m-2 s-1) and total chlorophyll content (3.39 mg g-1). Thus, it can be concluded that with the application of 200 ppm Pro-Ca growth regulator, the physiological parameters having the most dominant effect on increasing the yield of apricot, can be enhanced to get better returns.