著者
Keiko SATO Yoshinori IKOMA
出版者
日本農業気象学会
雑誌
農業気象 (ISSN:00218588)
巻号頁・発行日
pp.D-19-00023, (Released:2019-12-14)
参考文献数
21
被引用文献数
1

In recent years, peel puffing and delayed peel pigmentation have been observed in satsuma mandarins, possibly due to global warming. The effects of elevated temperatures during fruit maturation on fruit quality have been well studied. However, little is known about the effects of elevated temperatures during the flowering to physiological fruit drop stage. To clarify this, we controlled the air temperatures around satsuma mandarin trees during the flowering to physiological fruit drop stage (Period A) and at the fruit maturation stage (Period B). Temperatures were set to 2°C or 4°C above the recent mean temperatures because global warming is predicted to increase the mean global surface temperature by 2°C-4°C in this century. We then investigated the effects of the elevated temperatures on fruit quality in varying combinations for Periods A and B. Peel puffing was increased when temperatures were increased by 4°C during Period A or by 2°C or 4°C during Period B. Peel puffing was also increased with increases of 2°C during Period A; however, those results were not statistically significant. Peel pigmentation was enhanced when temperatures were increased by 2°C or 4°C during Period A but deteriorated when the temperature was increased by 2°C during Period B. Fruit weights were increased when temperatures were increased during Period A, but this was partly due to higher peel percentages. The peel percentages tended to be higher after temperature increases in either Period A or Period B. The soluble solid concentrations and acidity levels of the fruit juices tended to be lower after temperature increases during Period A, although not all of those changes were statistically significant. In conclusion, we found that temperature increases of 2°C or more above the recent mean temperatures during early fruit development can be detrimental to fruit quality by increasing peel puffing.
著者
Keiko Sato Yoshinori Ikoma
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-003, (Released:2016-10-08)
被引用文献数
7

To improve labor-saving during harvests, the efficiency of handpicking fruit was examined for the satsuma mandarin with the plant growth regulators gibberellin (GA), prohydrojasmon (PDJ), and ethephon (ET). In this study, concentrations of plant growth regulators were set 5 mg·L−1 for GA and 50 mg·L−1 for PDJ, respectively. Spraying of a GA plus PDJ solution on Aug. 27, Sep. 21, and Oct. 27 (triplicate spraying) improved the success rate of handpicking (SRH), as compared with a control. Furthermore, ET treatment in addition to triplicate spraying of GA plus PDJ increased SRH. A one-time treatment of GA plus PDJ also showed a significant effect on handpicking efficiency when applied in mid to late September. It was clear that the effect of GA plus PDJ on SRH was improved when 400 mg·L−1 ET was used instead of 200 mg·L−1, but this ET concentration (400 mg·L−1) caused massive leaf abscission (data not available). Spraying with 300 mg·L−1 ET alone showed 37.1% leaf abscission: therefore, we assumed that a GA plus PDJ treatment with a combination of less than 300 mg·L−1 ET would increase peel firmness without serious leaf abscission and a negative effect on SRH. In addition, the soluble solids and the acidity in the combination spraying of GA plus PDJ in late September with 300 mg·L−1 ET and less were almost the same as the control. Thus, our results indicated that the treatment of 5 mg·L−1 GA plus 50 mg·L−1 PDJ in late September combined with ET (200 mg·L−1 < ET < 300 mg·L−1) from late October to early November was suitable for increasing SRH without impairing fruit quality and causing serious leaf abscission.