Resistance potential of wheat germplasm (Triticum aestivum L.) against stripe rust disease under rainfed climate of Pakistan.

Enduring resistance based on partial resistance is very noteworthy and successful way to combat against the stripe rust dilemma (Puccinia striiformis West. tritici) in wheat crop. For this purpose, field-based screening to evaluate partial resistance is very important for the plant breeders of developing countries, who usually handle hundreds of lines at a time. A two years study was conducted during 2005-2007 to determine variability for field based-partial resistance against stripe rust among 188 wheat breeding lines grown at the experimental area of the PMAS - Arid Agriculture University, Rawalpindi, along with Morocco as susceptible check. The wheat lines and commercial varieties were tested in the field under natural climatic conditions of arid zone of Pakistan. Average Coefficient of Infection (ACI) and Relative Resistance Index (RRI) values of two-year trial showed that out of 188 cultivars, 150 responded with RRI value ≥7 ≤9 and were found in the desirable range; 28 cultivars were included among the acceptable range having RRI value ≥5 ≤ 7. However, only 10 cultivars showed RRI value <5 and were placed under undesirable range.