Marker-Assisted Pyramiding of Downy Mildew-Resistant Gene Ppa3 and Black Rot-Resistant Gene Xca1bo in Popular Early Cauliflower Variety Pusa Meghna

Abstract

Cauliflower is an important extensively grown cool season vegetable in India. Black rot and downy mildew are major devastating diseases reducing yield and quality of the crop. To tackle these through host plant resistance, a marker-assisted backcross breeding method was followed to pyramid a black rot-resistant gene (Xca1bo) and a downy mildew-resistant gene (Ppa3) from donors BR-161 and BR-2, respectively, into the background of Pusa Meghna cauliflower cultivar. Marker-assisted backcross breeding was followed up to BC2 generation using SCAR marker ScOPO-04833 and SSR marker BoGMS0624 for black rot and downy mildew resistance genes in foreground selection, respectively. In background selection, at each stage of backcrossing, 47 parental polymorphic SSR markers were used. The graphical genotyping of the five two-gene (Xca1boXca1boPpa3Ppa3) homozygous BC2F2 plants showed an average recovery of 85.44% of the Pusa Meghna genome with highest genome recovery of 91.7%. The genome contribution of donor parents (BR-161 and BR-2) was 8.26 with 6.34% of residual heterozygousity. The backcross derived pyramided lines BC2F2:3-7-16 and BC2F2:3-7-33 showed high resistance to both the diseases and exhibited higher yield and vitamin C content as compared with recipient parent Pusa Meghna. It is, therefore, evident from this study that resistant genes can be introgressed successfully into a Pusa Meghna cultivar without any yield penalty, benefitting farmers with reduced input cost and consumers with chemical residue free produce. Besides, the pyramided lines carrying dominant resistant genes can be exploited in a hybridization programme to develop hybrid(s) in cauliflower.

Advances in Multi-Omics Approaches for Molecular Breeding of Black Rot Resistance in Brassica oleracea L.

“…Interestingly, these markers showed 100% accuracy in differentiating the resistant and susceptible plants of cauliflower breeding lines. Very recently, the SCAR marker, ScOPO-04833, was used as a foreground marker to introgress the black rot-resistance gene ( Xca1bo ) during marker-assisted pyramiding of black rot-resistance gene Xca1bo and downy mildew-resistance gene Ppa3 in popular early cauliflower variety Pusa Meghna ( Saha et al, 2021 ).…”

Marker-assisted introgression lines of elite Indian mustard (Brassica juncea) cultivars for resistance against white rust (Albugo candida)

“…However, the molecular marker-assisted backcross breeding approach (MABB) is a more precise and quick approach for the development of white rust resistant (WRR) introgression lines of elite cultivars (Varshney et al 2010). Molecular marker-assisted breeding has been successfully employed in the introgression of genes conferring resistance to white rust (Somers et al 2002, Arora et al 2019, Singh et al 2020, downy mildew (Saha et al 2021), Sclerotinia stem rot (Rana et al 2017), blackleg (Saal et al 2005;Kalia et al 2017), clubroot (Kawasaki et al 2021;Hirani et al 2016;Kaur et al 2022) disease affecting Brassica species. Considering all these facts, the present study was, therefore, conducted to develop WRR lines in the background of elite mustard cultivars, namely, DRMR150-35, NRCHB101, DRMRIJ-31 and NRCDR-02 having high yielding potential, better seed quality, oil content and good market price using marker-assisted backcross breeding approach.…”