著者

Chitose Honsho

出版者

The Japanese Society for Horticultural Science

雑誌

The Horticulture Journal (ISSN:21890102)

巻号頁・発行日

pp.QH-R001, (Released:2022-12-13)

被引用文献数

5

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Self-incompatibility in Citrus species is an important trait related to fruit set and seed formation. In particular, self-incompatible citrus varieties combined with sufficient parthenocarpy produce seedless fruits. The characteristics of self-incompatibility have been studied for many years, and essential traits, such as pollen tube elongation behavior and self-incompatibility genotypes, have been characterized. Recently, it has been shown that the genetic mechanism of self-incompatibility in citrus varieties is S-RNase-based gametophytic self-incompatibility. To date, 18 S-RNases (17 self-incompatible alleles and 1 self-compatible allele) have been identified. The DNA markers for S-RNases can enable the early identification of self-incompatibility/compatibility status. The expression of self-compatibility in Citrus species is ascribed to the presence of the self-compatibility Sm allele, which is a defective S-RNase, and to the suppression of S-RNase expression. Polyploidization induces self-compatibility in Citrus species: Citrus tamurana ‘Hyuganatsu’ is substantially self-incompatible; however, its bud mutation, ‘Nishiuchi Konatsu’, is self-compatible. ‘Nishiuchi Konatsu’ is diploid; however, it forms unreduced pollen, which causes the breakdown of self-incompatible reaction when self-pollinated because of a competitive interaction within the same individual. In addition, after fertilization by unreduced pollen, seed formation is also inhibited by triploid block caused by interploid hybridization between diploid pollen and haploid egg cells. Therefore, ‘Nishiuchi Konatsu’ shows self-compatibility regardless of the self-incompatibility haplotype and produces fruits with few seeds. The seedlessness trait could be beneficial for citrus breeding in the future; however, the genetic mechanisms involved in the expression of this trait remain unclear. This review focuses on the recent advances in the genetics of self-incompatibility in citrus plants, implicating the mechanisms involved in self-incompatibility and their applications for achieving the desired trait of seedlessness in citrus fruits.

著者

Takuya Tetsumura Takashi Takita Shogo Funaki Kutaro Kusano Kasumi Kuhara Kotaro Manabe Kazuki Manabe Yasuhiro Udatsu Mitsuhiro Matsuo Shuji Ishimura Chitose Honsho

出版者

The Japanese Society for Horticultural Science

雑誌

The Horticulture Journal (ISSN:21890102)

巻号頁・発行日

pp.QH-010, (Released:2022-08-09)

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The growth and quality of the fruit from adult ‘Fuyu’ and ‘Hiratanenashi’ Japanese persimmon (Diospyros kaki Thunb.) trees that were grafted onto D. kaki seedlings (S), Rootstock-a (R-a), ‘MKR1’, and own-rooted (O-R) trees planted in February 2003 were observed from 2015 to 2021, when almost all of the trees entered stable, high-productive phases and the fruit quality was stable. The trees that were grafted onto ‘MKR1’ were still dwarfed but produced fruit efficiently. After disbudding took place, in the first half of stage I of the double sigmoid growth curve there was a certain period of time when the fruit of the ‘Hiratanenashi’ trees that were grafted onto ‘MKR1’ was lighter than the trees that had been grafted onto S. However, in the second half of stage I, the fruit of the former was heavier than that of the latter, and the flesh cells of the former were larger than that of the latter. In stage II and III, the fruit of the latter grew faster and became significantly heavier just before the harvest. The fruit growth of the ‘Fuyu’ trees that were grafted onto R-a was retarded compared to the growth of trees that were grafted onto ‘MKR1’ throughout most of the growing period. Heavy disbudding (HD) effectively increased the fruit weight of the ‘Hiratanenashi’ trees that were grafted onto ‘MKR1’ in a certain time period in stage I and in stage III compared to normal disbudding. HD also improved the fruit growth of the ‘Fuyu’ trees that were grafted onto ‘MKR1’, although this was not as effective as the ‘Hiratanenashi’ fruit growth. The weight of the harvested ‘Fuyu’ trees’ fruit increased in the following order: R-a, ‘MKR1’, O-R, and S. The ‘Hiratanenashi’ trees that were grafted onto ‘MKR1’ had the lightest fruit among the rootstocks, but the HD treatment for the trees that had been grafted onto ‘MKR1’ increased the fruit weight, and the difference disappeared. The soluble solids concentration of ‘Fuyu’ fruit was the highest in ‘MKR1’ and the lowest in R-a. ‘Hiratanenashi’ fruit had the highest concentration of soluble solids in S and the lowest concentration in O-R. The level of firmness of ‘Fuyu’ fruit flesh was the hardest in ‘MKR1’ and the softest in R-a, whereas the level of firmness of ‘Hiratanenashi’ fruit was the same among the rootstocks. Although the a* value of ‘Fuyu’ fruit skin color was the same among the rootstocks, the a* value skin color of ‘Hiratanenashi’ fruit was the highest in ‘MKR1’ and R-a and the lowest in S. These results suggest that the persimmon rootstock partly affects growth and quality of the fruit, although there are differences in the reactions between scion cultivars.

著者

Takuya Tetsumura Shuji Ishimura Takashi Takita Shogo Funaki Hiroharu Uchida Takumi Hidaka Syo Haranoushiro Yasuhiro Udatsu Mitsuhiro Matsuo Chitose Honsho Hideaki Asakuma

出版者

The Japanese Society for Horticultural Science

雑誌

The Horticulture Journal (ISSN:21890102)

巻号頁・発行日

pp.UTD-020, (Released:2018-10-26)

被引用文献数

6

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The field performance of ‘Taishuu’ Japanese persimmon trees grafted onto clonally propagated rootstocks, ‘MKR1’ and FDR-1, was investigated over 10 years. These results were then compared with the performance of trees grafted onto seedling stocks (S) and own-rooted trees derived from micropropagation (O-R). ‘Taishuu’ scions on ‘MKR1’ and FDR-1 rootstocks grew well initially, but stopped growing taller at seven years after planting. Total shoot length and trunk cross-sectional area (TCSA) increased annually in all trees, while the differences in these parameters between S or O-R trees and ‘MKR1’ or FDR-1 trees continued to increase year after year. The graft union of trees grafted onto ‘MKR1’ swelled, and FDR-1 rootstock overgrew the ‘Taishuu’ scion. Trees grafted onto both ‘MKR1’ and FDR-1 bore female and male flowers soon after planting, and the percentage of shoots with female flowers relative to total shoots in ‘MKR1’- and FDR-1-grafted trees were higher than that in S and O-R trees each year. The numbers of shoots with male flowers varied from year to year in ‘MKR1’- and FDR-1-grafted trees, but did not appear to increase yearly. ‘MKR1’- and FDR-1-grafted trees almost completely inhibited secondary shoot occurrence in mid-June, and the percentages of dropped fruitlets between the middle of May and the end of July were almost always lower for ‘MKR1’- and FDR-1-grafted trees than for S and O-R trees. Cumulative yield efficiencies according to TCSA, canopy area, and canopy volume showed that ‘MKR1’- and FDR-1-grafted trees produced fruit most efficiently, although the total yields per tree were not significantly different between rootstocks. There were no significant differences in fruit quality between the rootstocks, except for the number of seeds. Concentric cracking and stylar-end cracking occurred in fruit of trees grafted onto ‘MKR1’ and FDR-1. However, the differences between the rootstock types were not large. The harvest date of ‘MKR1’ trees was significantly earlier than that of S and O-R trees. In conclusion, ‘MKR1’ and FDR-1 are both satisfactory dwarfing rootstocks for ‘Taishuu’, with high yield efficiency and inhibition of early fruit drop.

著者

Tomohiro KONDO Chitose HONSHO

出版者

Japanese Society for Tropical Agriculture

雑誌

Tropical Agriculture and Development (ISSN:18828450)

巻号頁・発行日

vol.62, no.3, pp.132-135, 2018 (Released:2018-10-12)

参考文献数

10

著者

Ziaurrahman Hejazi Shuji Ishimura Chitose Honsho Takuya Tetsumura

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-125, (Released:2017-11-08)

被引用文献数

10

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A practical dwarfing rootstock for the persimmon (Diospyros kaki Thunb.), ‘MKR1’, is normally propagated by cuttings collected from root suckers. However, optimal conditions for propagating leaf-bud cuttings from this variety have not been researched. Thus, several methods influencing survival, rooting and root system structure were investigated in the present study. Cuttings planted in late June survived and rooted better than those planted in late July and August, and the rooted cuttings planted in late June also survived winter better. The two different irrigation methods, either a mist system, or a tray with a polyethylene tent (tray-polyethylene-tent, or TPT) did not significantly affect survival and rooting. However, the primary root length was longer in the TPT and the root dry weight was heavier under the mist system. Although the rooting medium did not significantly affect the survival of cuttings, the rooting percentage of cuttings planted in perlite was the lowest. The cuttings planted in peat in late June and placed under the mist system had adventitious root initials 17 days after planting and adventitious roots were observed on the cuttings by 22 days after planting. A quadratic regression curve predicted that the highest rooting percentage would result from treatment of ‘MKR1’ cuttings with approximately 2000 mg·L−1 indole-3-butyric acid (IBA), while a different curve predicted that the lowest root number would result from treatment with approximately 1000 mg·L−1 IBA. Interestingly, more than 50% of the cuttings treated with a quick dip in 0 mg·L−1 IBA successfully rooted. Although the treatment with a higher IBA concentration resulted in greater root system development on the rooted cuttings, treatment with very high IBA concentrations such as 4000 or 5000 mg·L−1 caused fading of leaves and dieback of cuttings.