Fruit development affects fruit quality and quantity.Study of fruit development on the molecular level is very important step toward improvement of fruit production. Setting a comparison between dry- and fleshy-fruit species, across different stages of fruit development, is one way of studying the key factors regulating fruit development. The Solanaceae family found promising in this regard, in which many berry and dry fruit species belong to a common evolutionary history and genetic ancestry; thus theexpression level and role of many similar genes can be compared between two different fruit-type species but arehighly similar in their genetic backgrounds as a member of the solanaceace family.To investigate the molecular processes important in fruit development and differentiation, two model plants were used; tomato (Solanum lycopersicum)and flowering tobacco (Nicotiana sylvestris). In comparison between Tomato and flowering tobacco,this paper study the expression level of ten candidate genes hypothesized to play a role in the development of dry vs fleshy fruits. RT-PCR and qRT-PCR were used to assess expression in different tissues and at different developmental stages.