Comparison of fruit ripening of "Maekawa jiro" persimmon [Diospyros kaki] grown in the plastic house and the open field
2005
Ito, H.(Mie-ken. Agricultural Technical Center, Ureshino (Japan)) | Nishikawa, Y. | Maegawa, T. | Wada, K.
Fruit ripening process of 'Maekawa Jiro' persimmon (Diospyros kaki), grown in the plastic house and the open field, was investigated from 1999 to 2001. The plastic house was covered with polyvinyl chloride film from early January to late June or early July and then uncovered. Additionally, the plastic house was heated at night from early January to early June. Air temperature in the plastic house was higher than that in the open field before full bloom and for 120 days thereafter. The plastic house-grown fruits began to color about 130 days after full bloom, which was approximately 20 days later than that of the open field-grown fruits; subsequent coloring in the former was also slower. Sucrose content in the open field-grown fruits increased gradually concurrent with the color development, whereas that of the plastic house-grown fruits did not increase appreciably until about 180 days after full bloom; it increased rapidly as the fruits approached maturity. Compared with the open field-grown fruits, the plastic house-grown fruits attained the same Brix and flesh firmness at a lower index of coloration at maturity. We attribute this to a possible high-temperature-mediated inhibition of pigment formation. These results indicate that the plastic house-grown 'Maekawa Jiro' persimmon fruits accumulated more sugars at a softer flesh firmness for the same degree of coloration. Hence, plastic house-grown 'Maekawa Jiro' persimmon fruits 'should be harvested when the fruit skin at the apex becomes 5 to 6 according to the standard color chart.
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