| Budget Amount *help |
¥2,200,000 (Direct Cost: ¥2,200,000)
Fiscal Year 1997: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 1996: ¥1,400,000 (Direct Cost: ¥1,400,000)
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| Research Abstract |
Characters concerned on photopriodic response are seen as the important items for differentiation and expansion of distribution areas in the wild and cultivated rice species. The present research is mainly focused in fundamental problems in these field, which are remained as unsolved status.
Two cultivated (Oryza sativa and O.glaberrima) and 3 wild (O.perennis, O.breviligulata and O.longistaminata) species were used as the experimental materials. The main results are summarized as follows :
(1)In identification test, about 70% and 99% strains showed photoperiodically sensitivities in cultivated and wild species, respectively. Large differences in intra-species and localities were remarkably found.
(2)In critical day length test, the higher is latitude, the longer is the critical day length. Differentiations found in the same locality were differ from species statuses. It was noticed that population No.3 located adjacent to Assam State showed the largest intra-population's diversity in comparison with other sites in case of Bangladesh.
(3)In plant age test, wild species showed the later responses in comparison with cultivated species, and these diversities were continuously found even at the present time.
(4)In minimum treatment number test, 8 days were confirmed as he basic number of days, in which the flower primordium was formed in the lowest stage. These value was looked upon as the larger and the smaller in cultivaed and wild species, respectively, in comparison with the past data, and shown as the smaller diversity in the respective species.
(5)In accumulation test, the higher is the latitutde, the larger is the effectiveness, which was nearly the same both in cultivated and wild species.
(6)In conclusion, important role of photoperiodic characters subjected on evolution, differentiation and diveristy of the genus Oryza had been became clear.
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