Production Performance and Fruit Quality of Gamma-Irradiated Mutants of ‘Kinnow’ Mandarin ( Citrus nobilis Loureiro × Citrus deliciosa Tenora)

The study was performed on selected ‘Kinnow’ mandarin mutants developed through varying doses of gamma irradiation: 15, 20, 25 and 30 Gy. From the varied population, five putative mutants from each treatment were selected to study growth, yield, and fruit quality over 2 successive years (at the 6th and 7th year of tree age). Plant height and fruit yield were reduced by 49.65% and 65.91% in the mutant G‑20 developed at 30 Gy. Fruit weight and activity of phenyl ammonia-lyase (PAL) and pectin methylesterase (PME) enzymes were observed to differ in mutants. Lower vitamin C content was assayed in the putative mutants as compared to the wild type. The desired low-seeded mutants G‑6 and G‑9 were obtained with an average of between seven and eight seeds/fruit developed at 20 Gy as compared to 31 seeds/fruit in the wild type. The juice recovery percentage in these mutants had parallel values with the wild type. This mutation breeding approach has detected new breeding material exhibiting dwarf plants coupled with higher fruiting intensity, lower number of seeds per fruit, and improved fruit quality. The results revealed that gamma irradiation has the potential to develop ‘Kinnow’ mutants for their commercial exploitation and their use in future breeding programmes.