Recovery of Recurrent Parent Genome in a Marker-Assisted Backcrossing Against Rice Blast and Blight Infections Using Functional Markers and SSRs

Abstract

The most vital aspect of marker-assisted backcross breeding is the recurrent parent genome recovery. This enables the selection of only parents with recovered recipient/recurrent parent genome in addition to the targeted genes. The recurrent parent genome recovery (RPGR) ensures that non-desirable genomic segments are removed while the gene of interest is sustained in the recombined progenies without further segregations. This work was aimed at quantifying the RPGR of backcross populations with introgression of bacterial leaf blight resistance genes. Putra-1, a Malaysian elite variety, high yielding with inherent resistance to blast but susceptible to bacterial leaf blight (BLB), was crossed with IRBB60 which is resistant to BLB disease. The IRBB60 has four Xoo resistance genes—Xa4, xa5, xa13 and Xa21. Tightly linked polymorphic functional and SSR markers were used for foreground selection at every stage of backcrossing to select progenies with introgressed target genes. Background selection was done to quantify the percentage of RPGR in the selected lines using 79 confirmed polymorphic microsatellites. Result obtained showed that the percentage of RPGR was 80.11% at BC1F1, 95.30% at BC2F1 and 95.9% at BC2F2. The introgression of Xa4, xa5, xa13 and Xa21 Xoo resistance genes were faster through the adopted marker-assisted backcross breeding compared to what could be obtained through conventional breeding. All the 16 selected lines displayed resistance to BLB with three lines showing high resistance to the disease. The blast resistance contained in the genetic background of Putra-1 was also sustained in all the selected lines. The newly developed lines were recommended as new rice varieties for commercial cultivation.

Introgressing cry1Ac for Pod Borer Resistance in Chickpea Through Marker-Assisted Backcross Breeding

“…The recurrent parent genome recovery in BC 2 F 2 plants was higher (91.3%) in this study as compared to 87.5% genetic similarity to the recurrent parent obtained after two backcrosses through conventional breeding ( Venkatesh et al, 2015 ). A recurrent parent genome recovery of 95.9% in BC 2 F 2 rice plants was reported using polymorphic SSR markers by Chukwu et al (2020) . The marker-assisted backcross breeding is a dynamic approach for conveniently recognizing plants that have recovered over 98% of the recurrent parent genome in two to three backcross generations depending upon the availability of polymorphic markers ( Stojsin 2010 ).…”

Marker-Assisted Introgression and Stacking of Major QTLs Controlling Grain Number (Gn1a) and Number of Primary Branching (WFP) to NERICA Cultivars

“…For example, NERICA4 × ST6 lines were observed to have the lowest maximum RPGR at 87.7%. The low RPGR observed in these lines could have been avoided if the analysis was carried out as early as BC 1 generation [ 19 , 41 ]. Nowadays, background selection at an early generation through GBS is cost-efficient for MAB programs.…”

Development of bread wheat (Triticum aestivum L) variety HD3411 following marker-assisted backcross breeding for drought tolerance

“…Since, the majority of gametes in BC1F1 were segregating, random fusion might lead to combinations containing recurrent parent genomes, which could lead to enhanced recovery of RPG at the cost of residual heterozygosity. An MABB study by Chukwu et al, 2020 reported a recurrent parent genome recovery of 80%-86.4% from BC 2 F 1 to 93.2%-98.7% from BC 2 F 2 , after one generation of selfing. Similar reports were presented by Bellundagi et al (2022) for wheat and Miah et al (2015) in rice.…”