Studies on Mutation Breeding in Mandarin Variety Kinnow

The present study was undertaken to generate variability in Kinnow (Citrus nobilis Lour × C. deliciosa Tenora) using gamma radiation. Four hundred buds of Kinnow were irradiated at 30 Gy and budded on rough lemon ischolar_mainstock in February 2007. The resulting 188 MV1 plants were planted in the field in October 2009 and observations in the present trial were recorded from 2015 to 2018. The number of bold seed per fruit ranged from 0.4 to 30.8 in the population raised from irradiated buds. Out of all the branches, 6.4% had bold seed number less than 10.3 per fruit, 39.4% had bold seed number from 10.3 to 20.3 per fruit and 54.7% plants had bold seed number more than 20.3 per fruit. The average fruit weight in treated population ranged from 94.3 to 253.2 g, with 46.8% bearing small sized fruits, 44.3% bearing medium sized fruits and 8.9% bearing large sized fruits. High variability was also observed for plant height, plant spread, pollen viability and total soluble solids. Among the 188 MV1 plants, eleven Kinnow mutants (seven solid mutant trees and four mutant branches) having average seed number less than eight were identified, showing distinct desirable characters and were compared in detail with parent variety Kinnow. One of the low seeded mutants was released as a new variety named 'PAU Kinnow-1' for cultivation in Indian Punjab.