著者

Chikako Honda Hiroshi Iwanami Katsuki Naramoto Tsutomu Maejima Kyohei Kanamaru Yuki Moriya-Tanaka Toshio Hanada Masato Wada

出版者

一般社団法人 園芸学会

雑誌

The Horticulture Journal (ISSN:21890102)

巻号頁・発行日

pp.OKD-010, (Released:2016-10-18)

被引用文献数

14

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In common apple cultivars with white flesh and red skin, it is known that fruit overload lowers fruit quality, and that skin anthocyanin concentrations are reduced by bagging treatment and warmer climatic conditions. In this study, the effects of these factors on anthocyanin accumulation in the flesh of red-fleshed apples were investigated using ‘Geneva’ and ‘Pink Pearl’ apple cultivars. Excess fruiting resulted in decreased anthocyanin concentration in the flesh and the titration acidity of the fruit in both cultivars. Fruit bagging treatments using double-layer paper bags revealed that anthocyanin was synthesized to a certain extent in the flesh under dark conditions in both cultivars. The treatment significantly reduced anthocyanin accumulation in the flesh of bagged ‘Geneva’ apples compared with unbagged fruit, but no inhibitory effect was clear in ‘Pink Pearl’ apples. In both cultivars, the anthocyanin concentration in the flesh of unbagged apples grown in sunlight was higher than that in unbagged apples grown in shade, whereas there was no difference between positions for bagged fruit. In apples grown in either sunlight or shade, no significant difference was found between anthocyanin concentrations in the sun-exposed side and shaded side of fruits. These results indicate that sunlight irradiation partially promoted anthocyanin accumulation in the flesh of unbagged ‘Geneva’ and ‘Pink Pearl’ apples and accelerated its accumulation on both the sun-exposed and the shaded side. A comparison of the fruit quality of ‘Pink Pearl’ apples grown in different climatic regions showed that apples harvested at Suzaka, a warmer region, were lower in firmness, starch index, and titration acidity and higher in soluble solids concentration compared with those from Morioka, a cooler region. The anthocyanin concentration in the flesh of ‘Pink Pearl’ apples from the trees grown at Morioka was more than ten-fold higher than that in apples from the trees grown at Suzaka. Our results suggest that an appropriate fruit load, growth in sunlight, and growth under cooler climatic conditions, may redden the flesh of red-fleshed apples, as is the case for common apples.

著者

Kenji Sakurai Hiroshi Iwanami

出版者

The Japanese Society for Horticultural Science

雑誌

The Horticulture Journal (ISSN:21890102)

巻号頁・発行日

pp.QH-009, (Released:2022-12-15)

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Based on hand pollination, 217 crabapple cultivars were examined to determine their self-fruitfulness potential. One hundred and six cultivars failed to self-pollinate for fruits set. More than 50% self-pollinated fruit were obtained from 29 cultivars. Especially, the fruit set of ‘Jiringo’, ‘Karafutozumi’, ‘Katherine Crab’, Malus hupehensis, M. scheideckeri, ‘Mary Porter Crab’, ‘Mokoto’, ‘Nepal Apple Collections No. 85-I-74-3 86090-3’, ‘Scheidecker Crab’, ‘Silver Moon Crab’, ‘Tachikaido’, and ‘Tea Crab 81105’ were more than 50% by self-pollination over two years. ‘Jiringo’, ‘Katherine Crab’, ‘Mary Porter Crab’, ‘Scheidecker Crab’, and ‘Tachikaido’ have the potential to be self-compatible cultivars because their self-pollinated fruits contain complete seeds. Non-pollinated fruits of M. scheideckeri, ‘Nepal Apple Collections No. 85-I-74-3 86090-3’, and ‘Tea Crab 81105’ may contain apomictic seeds. Moreover, self-pollinated fruits contained seeds and non-pollinated fruits contained no seeds, suggesting that ‘Karafutozumi’ and ‘Mokoto’ may be self-compatible and parthenocarpic. The study findings not only provide breeding material for self-compatible apple cultivars, but also have led to the discovery of new apomictic and parthenocarpic research materials.

著者

Shigeki Moriya Miyuki Kunihisa Kazuma Okada Hiroshi Iwanami Hiroyoshi Iwata Mai Minamikawa Yuichi Katayose Toshimi Matsumoto Satomi Mori Harumi Sasaki Takashi Matsumoto Chikako Nishitani Shingo Terakami Toshiya Yamamoto Kazuyuki Abe

出版者

一般社団法人 園芸学会

雑誌

The Horticulture Journal (ISSN:21890102)

巻号頁・発行日

pp.MI-156, (Released:2016-07-23)

被引用文献数

21

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During apple (Malus × domestica Borkh.) storage, a loss in fruit firmness can occur. This is frequently associated with mealiness, an undesirable trait. There have been studies, such as phenotypic analyses and transcriptomics, as well as others employing a transgenic approach, focusing on this trait. Certain genetic approaches, such as quantitative trait loci (QTL) approach, however, have not been attempted. In this study, to identify and characterize QTLs controlling flesh mealiness and to investigate their application in apple breeding, we performed classical QTL mapping based on a bi-parental population and a genome-wide association study (GWAS) of mealiness. Phenotypic data for mealiness allowed us to identify two QTLs in the bi-parental family located on linkage group 10. The GWAS discovered significant marker-trait associations on chromosomes 2, 9, and 10. The MdPG1 locus, located on chromosome 10, was identified as the locus with the strongest significance by both QTL mapping and GWAS, suggesting its primary contribution to flesh mealiness. Using a tri-allelic simple sequence repeat marker, Md-PG1SSR10kd, 10 kb downstream of the MdPG1 coding sequence, we divided apple accessions into six groups based on their genotypes. Among the six groups, the Md-PG1SSR10kd genotype “2/2” had the least mealy phenotype.

著者

Hiroshi Iwanami Yuki Moriya-Tanaka Chikako Honda Masato Wada

出版者

一般社団法人 園芸学会

雑誌

The Horticulture Journal (ISSN:21890102)

巻号頁・発行日

pp.CH-112, (Released:2015-02-21)

被引用文献数

1 2

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The thinning of flowers or fruit is an essential part of the commercial production of quality apples. Although chemical thinners are generally used in apple orchards throughout the world, hand-thinning remains essential for controlling crop load to improve fruit quality and return bloom. The objectives of this study were to investigate factors that determine the time required for hand-thinning and to elucidate cultivar-related efficiency of hand-thinning. In all cultivars, the time taken for hand-thinning per cluster became shorter after petal fall, but the degree of this decrease differed among cultivars. The time taken for hand-thinning depended on both how much and when natural abscission of fruitlets occurred. The times required for hand-thinning were very similar among clusters with four, five, or six flowers/fruitlets, which was twice as long as that required for clusters with two or three flowers/fruitlets. This means that the time required for hand-thinning clusters is critically reduced when the number of flowers/fruitlets within a cluster is three or fewer. The time required for hand-thinning clusters of axillary buds became significantly longer from bloom to 7 days after bloom, and then decreased gradually from 7 to 25 days after bloom. When the proportion of clusters with three or fewer fruitlets is 50% at 15 days after bloom, the planting area of the cultivar that a person is able to hand-thin (six hours per day) from 10 to 30 days after bloom was 24.3 a, which was 40% larger than that of a cultivar in which the proportion of clusters with three or fewer fruitlets is 50% at 30 days after bloom (17.4 a). Therefore, the introduction of cultivars in which fruit abscission occurs at an early stage and on a large scale is a solution for reducing the labor costs of hand-thinning.