https://doi.org/10.17113/ftb.62.01.24.8349

Supplement

Fruit Quality Assessment of Novel Hybrid Pummelo × Sweet Orange and Its Molecular Characterization Using Acidity Specific Markers

Raushan Kumar¹, Nimisha Sharma^1*, Anil Kumar Dubey¹, Radha Mohan Sharma¹, Shruti Sethi², Gyan Prakash Mishra³, Sandeep Mathur¹, Hatkari Vittal¹, Mukesh Shivran¹ and Neha Sharma⁴

¹Division of Fruits and Horticultural Technology, ICAR - Indian Agricultural Research Institute, 110012 New Delhi, India

²Division of Food Science and Postharvest Technology, ICAR - Indian Agricultural Research Institute, 110012 New Delhi, India

³Division of Seed Science and Technology, ICAR - Indian Agricultural Research Institute, 110012 New Delhi, India

⁴ICAR - National Research Centre on Plant Biotechnology, 110012 New Delhi, India

Article history:

Received: 5 September 2023

Accepted: 4 January 2024

Keywords:

acidity specific markers; ascorbic acid; antioxidants; nutritional quality; hybrids; pummelo; sweet orange

Summary:

Research background. There is considerable diversity in newly developed pummelo × sweet orange citrus hybrids. Most hybrids showed lower peel thickness and high juice yield but there is a lack of information on fruit quality parameters and molecular characterization. Therefore, the aim of the current study is to determine the content of antioxidants and properties of the fresh juice of 24 new pummelo × sweet orange citrus hybrids (Citrus maxima [Burm. f.] Osbeck × Citrus sinensis [L.] Osbeck) and the parental genotypes along with molecular characteristics determined using acidity specific markers.

Experimental approach. The correlation and estimate of inheritance of the fruit juice properties: ascorbic acid, total phenol, total flavonoid, total antioxidant, total soluble solid and sugar contents, pH, titratable acidity, along with sensory evaluation was performed. Molecular characterization of these hybrids was carried out using de novo generated acidity specific simple sequence repeat (SSR) markers.

Results and conclusions. The main constituents of the fruit juice of pummelo × sweet orange hybrids were observed in the range of w(ascorbic acid)=40.00–58.13 mg/100 g, total phenols expressed as gallic acid equivalents w(GAE)=40.67–107.33 mg/100 g, total antioxidants expressed as Trolox equivalents b(Trolox)=2.03–5.49 μmol/g, total flavonoids expressed as quercetin equivalents w(QE)=23.67–59.33 mg/100 g, along with other properties: total soluble solids=7.33–11.33 %, w(total sugar)=2.10–5.76 %, w(reducing sugar)=1.69–2.78 %, w(non-reducing sugar)=0.39–3.17 % and titratable acidity 1.00–2.11 %. The above parameters differed significantly in the fruit juice of the evaluated pummelo × sweet orange hybrids. Considering these parameters, the hybrids SCSH 17-9, SCSH 13-13, SCSH 11-15 and SCSH 3-15 had superior antioxidant properties in terms of these parameters. A higher heritability (≥80 %) was also observed for all juice properties. Molecular characterization of pummelo × sweet orange hybrids showed that >50 % of the hybrids were grouped with medium acidity parents. Both molecular and biochemical parameter-based clustering showed that interspecific hybrids exhibit transgressive segregation with increased antioxidants that help alleviate the health problems.

Novelty and scientific contribution. These newly developed pummelo × sweet orange citrus hybrids are a valuable source of high-quality antioxidants for a healthy diet. The identification of trait markers that enable selection at the seedling stage is of great benefit to citrus breeders, as the characteristic features of a mature tree are not yet visible at the juvenile stage.