Breeding of new pummelo cultivar ‘Gusangyou'

Abstract: A new pummelo cultivar named‘Gusangyou'was selected from local wild seedlings in Wenzhou, Zhejiang province. In 1998, some old pummelo trees were found distributing scatteredly in Gusang and neighboring villages of Cangnan county in fruit germplasm resources investigation, including one estimated at more than 100 years old and twenty-four top-grafted offsprings. The fruits were visibly distinguished with local and market prevailing red flesh pummelo cultivars through fresh red flesh and multiple seeds characteristics. It was thought a potential fine cultivar, because red flesh pummelo cultivars are popular among consumers on account of their fresh color and special nutritional value. Lycopene and beta carotene are the main colour pigments in red flesh pummelo, and they can be used as a precursor of vitamins which are considered functional in scavenging free radicals and anti-aging. We began to pay attention to selecting red flesh pummelo materials from the 1990 s, and finally found these old pummelo trees in Gusang village in 1998. After several years of field observation they were found fruitful ability and stable fruit quality. Through SSR, SRAP and SNP molecular markers identification, it was proved not synonym with local pummelo germplasm resources. In order to test its bearing stability, the twenty-four topgrafted trees were transplanted to Yuquan Gusangyou Plantation of Cangnan as the first generation in2001, and then reproduced two clonal generations by grafting separately in 2006 and 2012. The observation results showed that the fruit characteristics of three clonal generations could keep stable, such as fresh red flesh and multiple seeds. In order to further test its regional adaptability we grafted them at three sets. It was found satisfying fruit production capacity and good fruit quality, showing fresh red flesh, no bitter taste, no cross-pollination and stable high yield, and therefore it was thought there was a good application prospect.After the test of distinctness, uniformity and stability, the new pummelo cultivar‘Gusangyou'was registed by Zhejiang Forest VarietyApproval Committee in 2017 (S-SV-CG-004-2017) . In summary, the‘Gusangyou'fruit shows excellent appearance quality, characterised by oblate shape, faint yellow skin, small oil cell, smooth surface and mainly distinguished as fresh red pulp colour. The average single fruit weight, rind thickness and seed number is respectively 1.5 kg, 1.4 cm and 73. The segments of pulp vesicles are relatively uniform and the number per fruit ranges from 15 to 17, and the segment membrane is easily peeled. The‘Gusangyou'fruit also shows favorable characteristics in edible quality, mainly performed as crisp taste, tender without residue and non-bitter. The measurement results of fruit nutrition quality are as follows: fruit edible rate of 62.35%, flesh juice yield of 65.68%, total soluble solid of 9.18%, soluble sugar of 6.98%, titratable acid of 0.70%, vitamin C of 557.1 mg· kg^-1 and β-carotene of 0.504 mg· kg^-1. The average yield of8-10 years old normal bearing trees is 2 577-3 182 kg per 666.7 m².