Marker assisted introgression of gall midge (Gm4) and bacterial blight (Xa13) resistant genes in to tellahamsa rice cultivar

Tellahamsa is a high yielding, long-slender (LS) grain type rice variety with 120 days of duration. However, it is highly susceptible to rice Gall Midge (GM) and Bacterial Blight (BB). In order to improve Tellahamsa for resistance against Gm and BB, a gene each conferring resistance against Gm (i.e. Gm4) and BB (i.e. xa13) was introgressed into Tellahamsa. An introgression line of Samba Mahsuri (RP1) possessing Gm4 and xa13 genes and with fine-grain type was used as donor parent in a backcross breeding strategy for targeted introgression of the resistance genes. PCR based molecular markers RM547, RM22554 and LRR-del for Gm4 and xa13 promoter for xa13 genes were used for foreground selection of target genes in F₁, BC₁F₁ BC₂F₁ and BC₃F₁ generations, while 123 rice microsatellite markers polymorphic between the donor and recurrent parent were used to identify the best backcross plants, which not only possess the two target genes, but also have maximum recovery of recurrent parent genome at each generation. At BC₃F₆, four backcross derived line viz., WGL-1145, WGL-1146, WGL-1147 and WGL-1150 possessing Gm4 and xa13 genes, high yield, long-slender grain type, recurrent parent genome recovery ranging from 88.8–98.6% and closely resembling Tellahamsa were selected and advanced for further evaluation.