Natsushizuku' is an early maturing smooth skin type new cultivar of Japanese pear (Pyrus pyrifolia Nakai) released in 2004 by the National Institute of Fruit Tree Science, National Agriculture and Food Research Organization. It originated from the cross between 'Nashi Hiratsuka 25' ('Kousui'×'Kikusui') and 'Chikusui' in 1990. It was selected as a promising tree in 1998, and subjected to the 7th regional adaptability test of pear as Nashi Tsukuba 50 from 1999, conducted at 34 experimental stations in 34 prefectures in Japan. It was designated and registered as 'Nashi Norin 23' on September 15, 2005, and also registered as No. 16480 under the Seed and Seedlings Law of Japan on March 13, 2008. Compared with 'Kousui', tree vigor is a little stronger, the amount of fruit spurs is greater, and the amount of axillary flower buds is the same. It is cross-compatible with 'Kousui', 'Housui', 'Gold Nijisseiki' and 'Chojuro'. It blooms at the same time as 'Kousui', and ripens about one week earlier than 'Kousui'. It is resistant to black spot, and there is no serious problem of diseases or insect pests under standard spraying programs. The fruit is oblate in shape, weighs about 320g, and is as large as 'Kousui'. The fruit skin becomes somewhat russet when grown under non-bagging culture as well as under bagging culture. The flesh hardness is under 5.0 lbs, being as soft as that of 'Kousui'. The soluble solids content and the pH in juice average around 12% and 5.1, respectively, both of which are as high as those of 'Kousui'. The eating quality is the same as 'Kousui'.
雑誌名
果樹研究所研究報告
雑誌名(英)
Bulletin of the National Institute of Fruit Tree Science
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ニホンナシ新品種 'なつしずく'
nifs_report_No9p11-22p.pdf
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