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Matsumoto S.,Nagoya University | Soejima J.,Apple Inc | Maejima T.,Nagano Fruit Tree Experiment Station
Scientia Horticulturae | Year: 2012

Lopsided apple fruits were found in an orchard consisting of a single commercial cultivar Fuji and pollinizers of crab-apples under conditions of natural pollination. Speculating that it was caused by inadequate partial pollination, we devised an appropriate model. We artificially pollinated one out of five pistils of apple gynoecium, and then investigated the correlations among inadequate partial pollination, seed number, distribution, and fruit shape.It was speculated that a decrease in seed number and an increase in the rate of lopsidedness were caused by inadequate partial pollination. A deviation in seed distribution was also a factor in the occurrence of lopsided fruits. Since many of the main pollinator Osmia cornifrons visited a flower repeatedly at an orchard consisting of a single cultivar and pollinizers, we analyzed the effect of repeated pollination on increasing and improving seed number in fruits and fruit shape, respectively, using artificial pollination of a pollinizer and cultivars with various S-genotypes. Repeated pollination at 24-h intervals did not contribute to fertilization, but those at 4-h intervals contributed significantly as pollen parents of seeds in fruits. The ability of pistil fertilization was maintained until four days after flowering regardless of pollination, but once fertilization occurred, this pistil was not considered to contribute to seed production 24. h after initial pollination. Those results suggested that pollinizers in full bloom be shifted more than a day seemed unnecessary at an orchard with single commercial cultivar, and repeated artificial pollination must be done within one day. © 2012 Elsevier B.V.

Sugiura T.,Japan National Agriculture and Food Research Organization | Ogawa H.,Nagano Fruit Tree Experiment Station | Fukuda N.,Apple Inc | Moriguchi T.,Japan National Agriculture and Food Research Organization
Scientific Reports | Year: 2013

The effects of climate change on the taste and textural attributes of foods remain largely unknown, despite much public interest. On the basis of 30-40 years of records, we provide evidence that the taste and textural attributes of apples have changed as a result of recent global warming. Decreases in both acid concentration, fruit firmness and watercore development were observed regardless of the maturity index used for harvest date (e.g., calendar date, number of days after full bloom, peel colour and starch concentration), whereas in some cases the soluble-solids concentration increased; all such changes may have resulted from earlier blooming and higher temperatures during the maturation period. These results suggest that the qualities of apples in the market are undergoing long-term changes.

Akbari M.,Nagoya University | Maejima T.,Nagano Fruit Tree Experiment Station | Otagaki S.,Nagoya University | Shiratake K.,Nagoya University | Matsumoto S.,Nagoya University
International Journal of Agronomy | Year: 2015

"M.9" rootstock is considered as one of the most useful apple (Malus x domestica Borkh.) rootstocks; it produces dwarfing trees efficiently. As "M.9" rootstock shows a poor, brittle, and shallow roots system, we grafted "M.9" rootstocks onto "Marubakaidou" (M. prunifolia Borkh. var. ringo Asami Mo 84-A). We then propagated them by mound layering to establish a high-density root system. It was found that covering the roots with rice seed coat (RSC), RSC + smoked rice seed coat (SRSC), and vermiculite during mound layering was effective for the initiation of rooting. Utilizing RSC and SRSC seemed especially effective for producing "M.9" roots efficiently. © 2015 Matiullah Akbari et al.

Akbari M.,Nagoya University | Yamaguchi M.,Nagoya University | Maejima T.,Nagano Fruit Tree Experiment Station | Otagaki S.,Nagoya University | And 2 more authors.
International Journal of Agronomy | Year: 2016

We investigated S-RNase genotypes of nine useful Afghan apple cultivars including six original cultivars and one rootstock. We also determined S-RNase genotypes of 11 apple cultivars and lineages and seven rootstocks in Japan. We speculated regarding the unidentified parents of cultivars and lineages from the S-RNase genotypes and their fruit and branch characteristics and also identified mistaken parents. We compiled a database of the apple S-RNase genotypes of 622 apple cultivars investigated, which included a survey system of cultivar combinations showing those that were fully incompatible, semicompatible, and fully compatible, written in the Pashto language. © 2016 Matiullah Akbari et al.

Yara K.,Japan National Agricultural Research Center | Matsuo K.,Kyushu University | Sasawaki T.,Nagano Fruit Tree Experiment Station | Shimoda T.,Japan National Agricultural Research Center | Moriya S.,Japan National Agricultural Research Center
Applied Entomology and Zoology | Year: 2012

We describe here the parasitoid wasps Torymus sinensis Kamijo and T. beneficus Yasumatsu & Kamijo (early-spring and late-spring strains), which are introduced and indigenous natural enemies of the chestnut gall wasp Dryocosmus kuriphilus Yasumatsu, an invasive chestnut pest in Japan. We recently discovered specimens of T. koreanus Kamijo, endemic in Korea, among Torymus parasitoids collected from D. kuriphilus galls in a Japanese chestnut orchard. In this study we compare the composition of Torymus parasitoids emerging from D. kuriphilus galls before and after the release of T. sinensis. Before the release of T. sinensis, early-spring and late-spring strains of T. beneficus predominated (58. 3 and 20. 8% of specimens collected). However, a few years after the release, both T. beneficus strains had been almost completely displaced by T. sinensis. In contrast to the rapid decrease in T. beneficus, T. koreanus did not decrease drastically before and even after the release of T. sinensis (approximately 10-20% of specimens collected). These results suggest that not a few T. koreanus were present in the Japanese chestnut orchard investigated at least several years after the release of T. sinensis, although both the T. beneficus strains were rapidly displaced by T. sinensis during this period. © 2012 The Japanese Society of Applied Entomology and Zoology.

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