Changes in Photosynthetic Rate, Specific Leaf Weight and Sugar Contents in Mango ( L.)

ABSTRACT

To evaluate the cultivar variation in photosynthetic rate (Pn) of mango, observations were taken in 25 cultivars representing different agro-climatic region of the country at two stages i.e. full bloom (March) and developed fruit stage (May). Seven cultivars, Papatio, Lucknow Safeda, Neelam, Mulgoa, Khas-ul-khas, Himsagar and Nisar Pasand showed the higher Pn rate at both the stages, while nine genotypes, Kishan Bhog, Langra, Chausa, Kesar, Fazri, Vanraj, Fernandin, Dashehari and Mallika showed medium Pn rate at both the stages. Specific leaf weight (SLW), total sugar and reducing sugar contents in leaves were also estimated in five commercially grown mango varieties, viz., Dashehari, Langra, Chausa, Amrapali and Mallika during the day at three times, 7:30 a.m., 12:30 p.m. and 5:30 p.m. at flower bud differentiation (November) and full bloom (March) stage to evaluate the cultivar variation in photosynthate production and their translocation efficiency. Total sugar and reducing sugar contents were generally low during November, while SLW was observed at lower level in March in all the cultivars, indicated better photosynthate movement from leaves in March and SLW level increased likewise sugar content from morning to noon and decreased gradually till evening. Higher photosynthates production and greater translocation was observed in Chausa and Langra and its maximum level was recorded during full bloom stage (March). The study brings out the importance of SLW for screening the genetic stocks of mango cultivars with regard to photosynthetic rate and translocation of photosynthates from leaves to other plant parts.