1. This experiment was carried out aiming at exploring the relationship between the origin and the crossincompatibility of sweet potato varieties. Nine hundred and fifty five varieties, out of which 199 were Japanese local varieites, 542 were Japanese improved varieties and 214 were introduced varieties, were classified into 12 groups (from A to L) from the viewpoint of cross-incompatibility for every origin of varieties.
2. Japanese local varieties belong to either of group A, B or C except only one variety. Introduced varieties include every group, although about half of them belong to group B. Varieties which belong to each group other than A, B and C were those introduced from limited countries. Japanese improved varieties include most of 12 groups, and the varieties which belong to the groups other than A, B and C occurred only when foreign varieties were used as the parent for crossing.
3. It was observed whether the grouping of varieties based on cross-incompatibility agree or not among countries. It was difficult, however, to see the agreement in most cases because test varieties for the classification differ with countries. Therefore, it seems necessary to investigate internationally the relationship among countries as to the grouping of varieties through usage of common test varieties for classification and exchange of information in order to succeed in introducing and breeding of new varieties.

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Mesocotyl growth habits of floating rice, single- and double-transplanting rice varieties in South Vietnam were examined in darkness. Results obtained were as follows :
1. An average mesocotyl length was longer than 31 mm in all the floating rices and it was shorter than 11 mm long in all the double-transplanting rices. In the single-transplanting rices, on the other hand, it varied from 1 to 105 mm long.
2. Not only in the floating rices but also in the single- and double-transplanting rices, the length-width ratio of grain was above 2.1.
3. Stimulation of mesocotyl elongation by high temperature pre-treatment was not observed in both single- and double-transplanting rices whose mesocotyl length was shorter than 4 mm, though it was clearly observed in japonica type rices in Japan.

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1) Under the natural condition in Naze City of Amami-Oshima, the season of mango efflorescence is from January to the beginning of May, and the trees flower abundantly. But by the mango anthracnose enhanced with frequent rains in every month, all mango trees bear very few fruits numbering only two or three each.
2) The author tried to protect the mango trees from rain damage by covering vinyl films overhead of every trees. The results were very successful, cropping 89 fruits per tree averagely.

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De bovenvermelde stukken zijn de verhandelingen omtrent de speciale gemaakte studies op de mogelijkheid van het voortbrengen der bastvezels in Indonesia bestemd voor de goeniezak-f abricatie.
De proef-resultaten van het winnen der bastvezels, genomen werden vóór den Wereld Oorlog II, waren in Indonesia niet altijd bevredigend. Doch het kan heden wel mogelijk zijn dat de gemechaniseerd roselle aanplantingen op groote schaal in Lampung van Sumatra voordelig gedreven worden met toepassing van moderne technieken.
Het wordt overwogen dat Indonesia gemakkelijk eigen behoefte van dit product kan voorzien. Bovendien, in geval van de vraag door de wereldmarkt voor dit product later grooter wordt dan de aanbod, bestaat er in Indonesia groote mogelijkheid van het vermeerderen der productie om deze vraag tegemoet to komen.

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[in Japanese]

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