Huge losses in wheat yield are attributed to the invasion of various diseases, out of which, rusts, especially “stripe rust” has caused enormous yield losses in the recent years. Until now, P. striiformis has been controlled partly by growing genetically resistant cultivars and partly by spraying wheat crop with fungicides. However, the option of using fungicides may become even less favourable in the future as a result of restrictions in their use. Consequently, various methods like gene pyramiding, multillines, multivar and gene deployment, were proposed as a means of using race-specific genes in a less uniform manner to provide effective resistance over longer periods of time against plant diseases. To this date, theories and the release of multilines have increased, still the practical application of multilines/multivars is in its infancy. This study was done to provide more field data on the part of disease development and to assess yield loss to wheat yellow rust in heterogenous host population.This book, therefore, provides more field data on the part of use of multivars for the cheap and environment friendly control of yellow rust in the region where epidemic is frequent.