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

Abstract

Research background. There is substantial diversity in newly developed Pummelo × Sweet orange citrus hybrids. Most of the hybrids showed decreased peel thickness and high juice recovery but there is dearth of information regarding fruit quality parameters and molecular characterization. Therefore, the current investigation aimed to ascertain the variation in antioxidants and other biochemical properties for fresh juice of 24 new Pummelo × Sweet orange citrus hybrids (Citrus maxima [Burm. f.] Osbeck × Citrus sinensis [L.] Osbeck) and parental genotypes along with molecular characterization using acidity specific markers. Experimental approach. The correlation and inheritance estimate for fruit juice ascorbic acid, total phenols, total flavonoids, total antioxidants, pH, TSS, sugar, titratable acidity and sensory evaluation was carried out. Molecular characterization of these hybrids was carried out using de novo generated acidity specific SSR markers. Results and conclusions. The main biochemical constituents in the Pummelo × Sweet orange hybrids fruit juice were observed in the range of ascorbic acid (40.00–58.13 mg/L), total phenols (40.67–107.33 mg GAE/100 g), total antioxidants (2.03-5.49 DPPH µmol Trolox/g), total flavonoids (23.67–59.33 mg QE /100 g), and other biochemical constituents TSS (7.33-11.33 °Bx), total sugar (2.10-5.76 %), reducing sugar (1.69–2.78 %), non-reducing sugar (0.39–3.17 %), acidity (1.00–2.11 %). The Pummelo × Sweet orange hybrids evaluated were differed significantly for the above parameters in fruit juice. The hybrids SCSH 17-9, SCSH 13-13, SCSH 11-15 and SCSH 3-15 were found to have superior antioxidant properties in terms of these parameters. A higher heritability (≥80 %), also estimated for all the biochemical properties in the juice. Molecular characterization of Pummelo × Sweet orange hybrids showed that >50 % hybrids grouped with parents with medium acidity level. Both molecular and biochemical parameters-based clustering showed that interspecific hybrids exhibit transgressive segregation with enhanced antioxidants that help in alleviating the health problems. Novelty and scientific contribution. These newly developed Pummelo × Sweet orange citrus hybrids fruits are a valuable source of quality antioxidants of healthy diets. Identifying trait-linked markers that enable selection during the seedling stage is immensely advantageous to citrus breeders due to the prolonged period of juvenility when the characteristic features of a mature tree are not evident.