More than one-third of the world's population, including more than half of its population in India, depends on rice (Oryza sativa L.), which is also the most significant crop for making basic foods. In many agro-ecological settings, rice is farmed in India. By 2050, agricultural output on land that is now under cultivation must rise globally by 70% and in emerging nations by 100% if food insecurity is to be reduced. The host plant is infected by the rice blast fungus during many phases of crop growth, including the leaf, stem, neck, collar, node, and root. The largest problem facing rice breeders is the deterioration of resistance in the many rice types that have been produced throughout time. Consequently, developing resilient cultivars that are broad-spectrum resistance is a difficult undertaking. The major causes of the creation of virulent pathotypes of Magnaporthe, which make blast control a challenging work, are the wide host range, ongoing genetic variety, evolution, and host alterations. Because of this, and other factors, such as the economic significance of blast disease in rice production and human food, the Rice-Magnaporthe interaction pathosystem arose as a model system to research host-pathogen interaction. In our study, the progenies derived from crosses are showing complete resistance against rice blast fungus Pyricularia oryzae. The plant population are screened with natural inoculum under field condition in Raipur, Chhattisgarh. All the plants were highly resistance (HR reaction) to blast. The presence of genes is traced out using the linked molecular markers RM136 and RM7311 for Pi2 and RM224 for tracing the presence of Pi1K. Identification of map position of these molecular markers was accomplished by identifying BAC or PAC clones that simultaneously contained a hit from the marker (Sequence of either forward or reverse Primer). Based on correlative in-silico mapping and blast analysis markers were landed to a physical positions on BAC/PAC clones, which demarcated BAC/PAC clones (pseudo molecules from Nipponbare) for reported genomic location.

Rice blast, R gene, genetic mapping

In the present study the progenies were validated with the presence of two resistant genes against rice blast which confer broad-spectrum resistance to the population. The introgression of resistant genes into the elite varieties and with the help of marker assisted selection, resistant plants can be easily derived which is incorporated with R gene for P. oryzae. Further with the help of bioinformatics, more primers can be developed that can co-segregate with the resistant gene.

Devika Saha, Vijay Yadav and Anil Kotasthane (2022). Identification and Mapping of Pi1K and Pi2, Two Major Gene Conferring Resistance Against Rice Blast in the progenies derived from Safri-17 × PR-122 × Safri-17 × Aganni; Safri-17 × PR-122; Dubraj × PR-122. Biological Forum – An International Journal, 14(4a): 476-481.