My research covers the area of interaction of light in vital functioning of plants. Yield and development of specific trait is the ultimate goal of my research especially in area of gene transformation. There are two ways to achieve yield goal via transformation of insect resistant gene like Cry1Ac or to increase the physiological efficiency of plants via genetical modification. The latter methodology was adopted as done by Thiele et al in potato. Here, the same methodology was adopted in improving the physiology of cotton plants by transforming it with Phy B gene to enhance photosynthetic rate. The results have been promosing in view that they show increased expression of Phy B protein as well as Phy B mRNA untilmately boosting photosynthetic rate stomatal conductance, Relative growth rate, Net assimilation rate, relative leaf growth rate, higher number of smaller but thicker leaves, increased boll size and cotton yield. The results of this study support the idea that improving agricultural performance by altering phy B levels is feasible.