Samba Mahsuri (BPT 5204) is one of the most popular and high yielding rice variety, grown extensively in India and other Asian countries also. However, it is highly susceptible to blast disease, caused by the fungal pathogen Pyricularia oryzae. The near isogenic line C101LAC derived from LAC23 possessing Pi-1 gene was selected as donor, which is located on chromosome 11. The MAS useful to develop resistance line with highest recurrent parent genome within a short period. The C101LAC carrying resistant gene Pi-1 was crossed with Samba Mahsuri to generate the mapping populations. Foreground selection was carried out using linked marker RM 224 to identify the plants processing the target gene (Pi-1). The recovery of recurrent parent genome in each backcrossed generations was carried out through a set of 60 polymorphic SSR markers across the rice genome. Out of 123 positive plants for Pi-1 gene in homozygous condition, a single plant (#BL-40-21-86-28) was identified at BC2F2 generation carrying the Pi-1 gene with maximum recovery of recurrent parent genome (~). This line was advanced through selfing and ancestry based selection for agro-morphological traits and also evaluated against blast on Uniform Blast Nursery (UBN). At BC2F4 generation, five lines Viz., BL-40-21-86-28-19, BL-40-21-86-28-72, BL-40-21-86-28-101, BL-40-21-86- 28-208 and BL-40-21-86-28-256 with high level of resistance to blast were identified. A single line (#BL-40-21-86-28-208) was found very similar to the recurrent parent in number of panicles per plant, panicle length and grain yield per pant. This line was selected for further advanced to release as NIL or used as future breeding programme for incorporation of blast resistance. | Marker-assisted introgression of Pi-1 gene conferring resistance to rice blast pathogen Pyricularia Oryzae in the background of Samba Mahsuri
