Research for Tropical Agriculture
Online ISSN : 2187-2414
Print ISSN : 1882-8434
ISSN-L : 1882-8434
Volume 10 , Issue 2
Showing 1-7 articles out of 7 articles from the selected issue
Original Article
  • Shin YABUTA, Jun TOMINAGA, Shun-ichiro KAWASAKI, Thanankorn JAIPHONG, ...
    2017 Volume 10 Issue 2 Pages 51-56
    Published: 2017
    Released: May 29, 2018
    JOURNALS FREE ACCESS

    Jatropha (Jatropha curcas L.) has been widely introduced to the Tropics and Subtropics as an energy crop because it can be grown in the dry climate and in various soils without competing with food production due to its toxicity. Foliar application of BA (6-Benzyladenine) may increase the yield through enhancing the number of the fruit. However, too much fruit may also cause fruit drop and shortening of harvest due to exhaustion. This study investigated the effects of BA on the seed yield throughout the harvest season. 120 one year old cuttings were transplanted to the field on April 24, 2013, and 72 plants were treated with BA on September 6 when the first flowers appeared. The flowering percentage, the number of flower sets and fruit bunches were counted from the 9th day before the treatment started to the 148th day after starting the treatment (DAT). The number of fruit was counted on 69 DAT. Harvesting was started from 82 DAT, and the characteristics of the seeds were analyzed. The BA treatment reduced the number of fruit bunches towards the later harvest time by restricting the second and third flower set initiations. However, the number of fruit was greater in the BA treatment mostly due to the increased number of fruits for the first bunch. As a result, seed yield was higher in the BA treatment (44.0g plant -1) than in the control group (38.6g plant -1). As a further improvement of the yield would be expected through increasing the fruit bunches, the method of application should be tested.

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  • Ittetsu YAMAGA, Shigekazu NAKAMURA, Mitsuhiro KATO
    2017 Volume 10 Issue 2 Pages 57-63
    Published: 2017
    Released: May 29, 2018
    JOURNALS FREE ACCESS

    Blue mold caused by Penicillium italicum Wehmer is the major postharvest disease infecting satsuma mandarin fruits. We studied the effects of simultaneous ultraviolet (UV)-B and (UV)-C irradiation on the spore germination of P. italicum in vitro, scoparone production on the flavedo tissue, blue mold symptom occurrence on the inoculated fruit and internal fruit quality, peel color and rind injury in Citrus unshiu Marc. ‘Aoshima unshu’. The UV irradiation inhibited the P. italicum growth in vitro. In particularly, the UV-C + UV-B light for 10 s (UV-C:UV-B; 0.2:0.25 kJ∙m-2) reduced spore germination by 91%, 48 hours after inoculation. Subsequently, scoparone production on UV-treated fruit was observed. Additionally, disease incidence, soft rot area diameter, and mycelial growth diameter on the fruit treated with UV-C (2.4 kJ∙m-2) + UV-B (3.0 kJ∙m-2) irradiation 72 hours before inoculation were examined. The diameter and the incidence of soft rot areas were not reduced significantly by UV irradiation 5 days after inoculation. However, UV-C + UV-B irradiation, and UV-C irradiation reduced the diameter of mycelial growth on fruits. Additionally, UV-B + UV-C irradiation was effective at reducing the incidence of mycelial growth. UV-C at 2.4 kJ∙m-2 + UV-B at 3.0 kJ∙m-2 irradiation did not affect fruit quality with respect to soluble solid concentration, titratable acidity, peel color or rind browning.

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