Marker assisted selection: a paradigm shift in Basmati breeding

Marker assisted backcross breeding (MABB) provides a great opportunity for precise transfer of desirable donor segment by minimizing the linkage drag into a recurrent parent. In our lab, MABB was used for incorporating bacterial blight (BB) resistance genes (xa13 and Xa21) into the genetic background of Pusa Basmati1, which led to development of Improved Pusa Basmati 1 (Pusa 1460) as one of the first products of molecular breeding. Further, the parental lines of superfine grain aromatic rice hybrid Pusa RH 10 namely, Pusa 6A, Pusa 6B and PRR78 were improved for resistance to BB and blast by transferring genes xa13+Xa21 and Pi54 +Piz5, respectively. Presently, the pyramiding of genes for resistance to BB (xa13 and Xa21), blast (Piz5 and Pi54) and brown plant hopper (BPH; Bph 3, Bph 17, Bph 18, Bph20 and Bph 21) into Basmati rice varieties viz., Pusa Basmati 1121 and Pusa Basmati 6 is under way. In addition, a major QTL for salt tolerance (Saltol) is being transferred to Pusa Basmati 1121, which is widely grown in Haryana, the state having problem of salinity owing to underground brackish water. In order to develop genetically enhanced donor sources for resistance to biotic (BB, blast and BPH) and abiotic (salt tolerance, and phosphorus uptake) stresses in Basmati background, isogenic lines are being developed for major resistance genes/QTLs for respective stresses in the background of Pusa Basmati 1. Molecular mapping of fertility restorer gene(s) in Basmati restorer line PRR78 led to identification of two Rf gene linked molecular markers, RM258 and RM6100. Of these, RM6100 on validation in a set of rice germplasm showed 97.4% efficacy in identifying restorer lines from germplasm.QTL mapping using RIL population has unveiled several novel QTLs for grain and cooking quality traits. Molecular markers are also being routinely used for establishing variety/hybrids identity and authentication of genetic purity of hybrid seed lots.