Marker‐assisted simultaneous but stepwise backcross breeding for pyramiding blast resistance genes Piz5 and Pi54 into an elite Basmati rice restorer line ‘PRR78’

Abstract

Marker‐assisted simultaneous but stepwise backcross breeding (MASS‐BB) was utilized in the present study for pyramiding blast resistance genes, Piz5 and Pi54, from non‐Basmati donors, C101A51 and Tetep, respectively, into PRR78, an elite Basmati restorer line of rice hybrid, Pusa RH10. Marker‐assisted foreground selection coupled with stringent phenotypic selection and background analysis was carried out for hastening the recovery of recurrent parent phenome (RPP) and genome (RPG) in two separate backcross series to produce BC2F1 plants with individual blast resistance gene. The best BC2F1 plant from each backcross series was intercrossed, and the resultant F1 was selfed to pyramid both blast‐resistance genes into PRR78. The plants homozygous for both the genes in the F2 were advanced through pedigree selection to produce superior blast‐resistant F5 lines. Background analysis revealed that the RPG recovery was up to 91.6%. Improved versions of Pusa RH10 developed using the improved PRR78 lines (PRR78+Piz5+Pi54) performed on par with the original Pusa RH10 and showed resistance to blast disease both under artificial screening and at hot spot locations.

Recurrent parent genome recovery analysis in a marker-assisted backcrossing program of rice (Oryza sativa L.)

“…From the background analysis, the RPG recovery was found up to 91.6% in BC 2 F 1 generation for pyramiding blast resistance genes Piz5 and Pi54 into an elite Basmati rice restorer line 'PRR78' using marker-assisted stepwise backcross breeding [18]. The mean RPG recovery in BC 2 generation using computer simulated 97% in case of Swarna and Samba Mashuri; observed 95% in case of Swarna and Samba Mashuri [43].…”

“…It is evident from the results that phenotypic selection for agro-morphological traits of MR219 coupled with marker-assisted background analysis led to hastening the recurrent parent genome and phenome recovery. The use of MAS for background selection can be very effective when the number of polymorphic markers included in the study is large, but with only 20% SSR polymorphism between the parental lines, MAS for background selection is still a distant dream for resource-limited laboratories [18]. In that case, stringent phenotypic selection for the RPP recovery is a very feasible option for the maximization of RPG recovery [53,54].…”

“…Marker-assisted foreground selection and stringent phenotypic selection in each crossed generation ensure selection of plant with desirable alleles, which has maximum recurrent parent phenome recovery [18]. As a general rule, two to four markers per 100 cM can be efficiently used to accelerate the recovery of the RP in the early generations such as BC 1 or BC 2 [14,19].…”

Introgression of the high grain protein gene Gpc-B1 in an elite wheat variety of Indo-Gangetic Plains through marker assisted backcross breeding

“…The higher recovery of RPG was achieved mainly through stringent phenotypic selection followed by background selection using molecular markers. Background analysis exercised through phenotypic evaluation is reported to be useful in efficient recovery of the RPG [48]. It has been suggested that stringent phenotypic selection for the recovery of recurrent parent phenotype is a good substitute for background selection through molecular markers in terms of judicious use of resources [42,[49][50][51].…”

Field Evaluation of RD6 Introgression Lines for Yield Performance, Blast, Bacterial Blight Resistance, and Cooking and Eating Qualities

“…However, the introgression of resistant genes without maintaining or improving yield levels and the grain quality would offer no reward; as such, varieties would not be adopted by farmers. Different MAS approaches are now, in practice, using background and foreground selection [20,21], as well as combined approaches utilizing foreground selection with stringent phenotypic selection [22], and foreground selection coupled with stringent phenotypic selection and background analysis [21]. Such practices have aided in accurate and efficient gene transfer, including gene pyramiding, into desired varietal backgrounds.…”