Because of environmental and human health problems associated with excessive use of pesticides, there has been an increased emphasis on alternative methods of controlling insect pests, including host plant resistance to insects, which can play a pivotal role in integrated pest management. Sources of resistance to insects have been identifi ed long ago, but these have not been used effectively in crop improvement, because the levels of resistance are either too low or it is not possible to screen the test material under uniform and optimum insect infestation levels to identify lines combining desirable agronomic traits and resistance to insect pests (Sharma and Ortiz, 2002; Sharma et al., 2005). Thus, there is a need for improving the accuracy and precision of phenotyping for insect resistance. Once the phenotyping systems are developed, molecular markers can be used to accelerate the pace of development of insect-resistant cultivars, dissecting the genetic basis of resistance, identifying the location of underlying genes, and understanding the nature of gene action (Sharma et al., 2002).