Marker-Assisted Selection to Pyramid the Opaque-2 (O2) and β-Carotene (crtRB1) Genes in Maize

Sarankumar Chandran; Bharathi Pukalenthy; Karthikeyan Adhimoolam; Dhasarathan Manickam; Vellaikumar Sampathrajan; Vanniarajan Chocklingam; Kokiladevi Eswaran; Kavithapushpam Arunachalam; Laishram Joikumar Meetei; Ravikesavan Rajasekaran; Vignesh Muthusamy; Firoz Hossain; Senthil Natesan

doi:10.3389/fgene.2019.00859

Marker-Assisted Selection to Pyramid the Opaque-2 (O2) and β-Carotene (crtRB1) Genes in Maize

Front Genet. 2019 Sep 26:10:859. doi: 10.3389/fgene.2019.00859. eCollection 2019.

Affiliations

¹ Department of Plant Breeding and Genetics, Agricultural College and Research Institute, Tamil Nadu Agricultural University, Madurai, India.
² Department of Biotechnology, Agricultural College and Research Institute, Tamil Nadu Agricultural University, Madurai, India.
³ Department of Plant Biotechnology, Center for Plant Molecular Biology and Biotechnology, Tamil Nadu Agricultural University, Coimbatore, India.
⁴ Department of Soil Science and Agricultural Chemistry, Agricultural College and Research Institute, Tamil Nadu Agricultural University, Killikulam, India.
⁵ Department of Tree Improvement and Plant Breeding and Genetics, Central Agricultural University, Imphal, India.
⁶ Department of Millet, Center for Plant Breeding and Genetics, Tamil Nadu Agricultural University, Coimbatore, India.
⁷ Division of Genetics, ICAR-Indian Agricultural Research Institute, New Delhi, India.
⁸ Department of Plant Molecular Biology and Bioinformatics, Center for Plant Molecular Biology and Biotechnology, Tamil Nadu Agricultural University, Coimbatore, India.

Abstract

Maize is an excellent nutritional source and is consumed as a staple food in different parts of the world, including India. Developing a maize genotype with a combination of higher lysine and tryptophan, along with β-carotene, can help alleviate the problem of protein-energy malnutrition (PEM) and vitamin A deficiency (VAD). This study is aimed at improving lysine and tryptophan content by transferring opaque-2 (o2) gene from donor HKI163 to β-carotene-rich inbred lines viz., UMI1200β⁺ and UMI1230β⁺. For this purpose, F₁, BC₁F₁, BC₂F₁, BC₂F₂, and BC₂F₃ plants were developed using an o2 line HKI163 and two β-carotene-rich inbred lines, UMI1200β⁺ and UMI1230β⁺, as the parents. Foreground selection using the associated marker umc1066 for the o2 gene and the marker crtRB1 3'TE for the crtRB1 gene was used to select the target genes. A total of 236 simple sequence repeat (SSR) markers distributed evenly across the maize genome were employed for the background selection. To fix the crtRB1 allele in the BC₁F₁ stage, individual plants homozygous at the crtRB1 locus and heterozygous at the o2 locus were selected and used for backcrossing to produce BC₂F₁ plants. Furthermore, the selected heterozygous BC₂F₁ plants from both crosses were selfed to obtain the BC₂F₂ plants, which were then selected for the target gene and selfed to generate the BC₂F₃ lines. From each cross, five improved lines with homozygous marker alleles for the crtRB1 and o2 genes with a recurrent parent genome (RPG) recovery ranging from 86.75 to 91.21% in UMI1200β⁺×HKI163 and 80.00 to 90.08% in UMI1230β⁺×HKI163 were identified. The improved lines had good agronomic performance and possessed high lysine (0.294-0.332%), tryptophan (0.073-0.081%), and β-carotene (6.12-7.38 µg/g) content. These improved lines can be used as genetic resources for maize improvement.

Keywords: crtRB1; marker-assisted backcross breeding; opaque-2; quality protein maize; β-carotene.

Marker-Assisted Selection to Pyramid the Opaque-2 (O2) and β-Carotene (crtRB1) Genes in Maize

Authors

Affiliations

Abstract

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