Morphological Characteristics, Fruit Qualities and Evaluation of Reproductive Functions in Autotetraploid Satsuma Mandarin (Citrus unshiu Marcow.)

Miki Sudo,Masaya Kato,Kiichi Yasuda,Hisato Kunitake,Mai Sato,Hiroo Mukai,Akiyoshi Tominaga,Gang Ma,Masaki Yahata

doi:10.3390/agronomy11122441

Miki Sudo, Masaya Kato + Show 7 more

Open Access

https://doi.org/10.3390/agronomy11122441

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Abstract

The morphological characteristics and fruit quality of an autotetraploid plant selected from nucellar seedlings of Satsuma mandarin (Citrus unshiu Marcow.) were investigated. Additionally, in order to evaluate the reproductive potential of male and female gametes of the tetraploid Satsuma mandarin, reciprocal crosses with diploid cultivars were also carried out. The tetraploid had significantly thick and round leaves, as compared to those of the diploid Satsuma mandarin. The sizes of the flowers and pollen grains of the tetraploid were significantly larger than those of the diploid. Pollen fertility of tetraploid was high compared with that of the diploid. The tetraploid produced seedless fruits. The fruit weight of the tetraploid was equal to that of the diploid. Compared to the diploid fruits, the tetraploid fruit had less sugar contents and more organic acid contents. Although the tetraploid fruits showed similar traits to other Citrus tetraploids such as thick and hard peels, the tetraploid had a higher content of carotenoids in the flavedo than the diploid, and the rind color of the tetraploid was much better. In the reciprocal crosses between the tetraploid Satsuma mandarin and diploid cultivars, some seeds were obtained, and triploid progenies were obtained in all cross combinations.

Highlights

Satsuma mandarin (Citrus unshiu Marcow.) is an economically important fruit crop in Japan
The gametic seedlings may have been mixed with the nucellar seedlings because the tetraploid plant used in the present study was selected from seeds of diploid Satsuma mandarin
The tetraploid Satsuma mandarin investigated in the present study showed mostly the typical morphological characteristics and fruit quality of tetraploid Citrus and its related plants

Summary

Introduction

Satsuma mandarin (Citrus unshiu Marcow.) is an economically important fruit crop in Japan. Satsuma mandarin fruits have high quality juice, are easy to peel and have many functional components such as ascorbic acid, β-cryptoxanthin and hesperidin [1,2,3,4]. Satsuma mandarins are used for fresh consumption and for juice, preserve, candy, syrup and oriental medicine. The Satsuma mandarin produces seedless fruits because of its genetic sterility [5]. Using this trait, the Satsuma mandarin contributes to production of many excellent cultivars such as the ‘Kiyomi’ tangor, the ‘Shiranui’ mandarin, the ‘Harumi’ mandarin and the ‘Setoka’ tangor in Japan [6].

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