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

Partha Saha; Chandrika Ghoshal; Namita Das Saha; Aakriti Verma; Mohita Srivastava; Pritam Kalia; Bhoopal Singh Tomar

doi:10.3389/fpls.2021.603600

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

Front Plant Sci. 2021 Aug 23:12:603600. doi: 10.3389/fpls.2021.603600. eCollection 2021.

Authors

Partha Saha¹, Chandrika Ghoshal¹, Namita Das Saha², Aakriti Verma³, Mohita Srivastava¹, Pritam Kalia¹, Bhoopal Singh Tomar¹

Affiliations

¹ Division of Vegetable Science, Indian Council of Agricultural Research-Indian Agricultural Research Institute, New Delhi, India.
² Centre for Environment Science and Climate Resilient Agriculture, Indian Council of Agricultural Research-Indian Agricultural Research Institute, New Delhi, India.
³ Division of Genetics, Indian Council of Agricultural Research-Indian Agricultural Research Institute, New Delhi, India.

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 BC₂F_2:3-7-16 and BC₂F_2:3-7-33 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.

Keywords: MAS; black rot; cauliflower; downy mildew; resistance.