Important Fruit Traits Suitable for Processing a Citrus Variety and Selection Criteria for Breeding

Abstract

We have started to breed a new citrus variety suitable for processing to meet the recent consumer demand for processed fruits. To this end, it is a prerequisite to identify fruit traits suitable for processing. Questionnaire responses obtained from 18 processors indicated that fruit weight, yield rate, and seed number were particularly important for processing. Since the acceptable limits of these characters varied among the processing purposes, such as for jam and juice, we focused on the cut fruits involving a large volume for processing, to decide on a provisional selection criterion. A provisional criterion for the drip amount, considered as a problem for fruit processing so far, was also determined based on the questionnaire survey. Through this, we identified two fruit traits that were involved in the drip amount. Subsequently, we carried out interviews with three processors, and applied the provisional criterion for citrus breeding strains. Based on the results, selection criteria were confirmed as follows: In the primary selection stage, which has been examined mainly based on morphological surveys, citrus breeders should select strains with the following traits: ≧ 180 g for fruit weight, 3 ≦ for seed number, ‘little’ to ‘medium’ for juice amount, and ‘medium’ to ‘tough’ for pulp toughness. In the secondary selection stage, it was necessary for breeders to select candidates for commercial varieties based on additional evaluation, including the pulp ratio and drip amount, along with traits of ≧ 200 g for fruit weight, 3 ≦ for seed number, ≧ 80% for pulp percentage, and 1.60 g ≦ for drip amount (per 100 g of fruit).