Studies on growth and development of pomegranate (Punica granatum L.) fruit and seed with special reference to hard and soft seededness

Abstract

Studies were conducted in four pomegranates varieties on time of initiation and degree of lignification of seed testa which causes hard seededness. The physicochemical changes during growth and development of fruits were also investigated. Fruit growth pattern in pomegranate followed a simple sigmoid curve almost approaching a liner relationship. Length and breadth of the fruit, fresh weight of rind and weight of seed increased continuously from fruit set to maturity. During most stages of fruit development, the seeds constituted roughly half of the fruit weight. Dry matter content in fruits increased continuously till 50 days of fruit growth and then gradually declined towards maturity, but it seeds, dry matter content increased continuously from fruit set to maturity. Specific gravity of fruits was higher in early stage of fruit development and then gradually declined. TSS increased gradually during fruit development and acid content decreased with maturation of fruits. Both reducing and total sugars continued to increased during the development of fruits. The nitrogen and phosphorus content of both fruits and seeds was maximum and highest immediately after fruit set and second highest nitrogen content was seen at maturity. The potassium content of fruit was highest at 10 and 120 days of fruit growth. The seeds contained very high potassium content both immediately after fruit set and also at maturity. The micronutrient contents of fruits were high initially, after fruit set, they declined in the intermediate stages and finally reached maximum levels at maturity. The seeds had maximum micronutrient immediately after fruit set. Histological studies revealed that after 40 days of seed growth lignification started and it was more pronounced in hard seeded varieties.