The bulk (above 70%) of Pakistan's 6 million tons maize production comes from the Punjab province where farmers use predominately (90%) hybrid maize. However, hybrid covers about 30-40% of the maize area in Pakistan and farmers in the northern areas use open pollinated varieties (OPVs). Absolute replacement of OPVs with hybrids is not feasible due technical skills, resource limitations and financial constraints. Therefore, current study explored the grain yield potential of improved OPVs and their adaptation pattern at the different agro ecologies of Pakistan.