Manzanilla D.O.,International Rice Research Institute |
Paris T.R.,International Rice Research Institute |
Tatlonghari G.T.,International Rice Research Institute |
Tobias A.M.,International Rice Research Institute |
And 6 more authors.
Experimental Agriculture | Year: 2014
The risks of flooding in rice production include losses that can affect some 13 million ha of rice lands in Southeast Asia. This study integrated social and gender perspectives into the varietal evaluation process to contribute to planned faster uptake of submergence-tolerant rice (Sub1) varieties. In this study, the participatory varietal selection (PVS) process was used in eliciting male and female farmers' opinions with respect to selecting popular varieties with the SUB1 gene introgressed, for added tolerance of flash floods of up to two weeks. Fifteen Sub1 varieties and the farmers' local check were tested under the PVS researcher-managed (PVS-RM) trials, which involved farmers' preference analysis (PA). The farmers tested the pre-selected lines with the SUB1 gene in their own fields to further evaluate their performance under varying conditions. During flooding, farmers experienced lower production depending on water depth, timing with respect to rice growth stage, duration, frequency of occurrence and quality. On-farm PA results showed wide variability in the performance of the Sub1 varieties compared with local popular varieties. This implies the need for further testing of pre-released lines in terms of adaptability and the continuous development of rice genotypes for varying flood-prone rice ecosystems. Women are as knowledgeable as men because of the significant roles they play in rice production and food preparation. Moreover, farmers and breeders have almost the same criteria in choosing the best performing rice lines. Sensory tests revealed the eating and cooking qualities important to farmers. The findings of this study can provide feedback to breeding programmes to ensure a greater likelihood of adoption and ultimately increasing rice productivity in submergence-prone rice areas. Copyright © Cambridge University Press 2013.
Yin H.,Iwate University |
Akimoto M.,Obihiro University of Agriculture and Veterinary Medicine |
Kaewcheenchai R.,Prachinburi Rice Research Center |
Sotowa M.,Hirosaki University |
And 2 more authors.
Genes and Genetic Systems | Year: 2016
AA genome species in the genus Oryza are valuable resources for improvement of cultivated rice. Oryza rufipogon and O. barthii were progenitors of two domesticated rice species, O. sativa and O. glaberrima, respectively. We used chloroplast single-nucleotide repeats (RCt1-10) to evaluate genetic diversity among AA genome species. Higher diversity was detected in the American species O. glumaepatula and the Asian species O. rufipogon. Other chloroplast sequences indicated that O. glumaepatula shares high similarity with O. longistaminata.Insertions of retrotransposable elements, however, showed a close relation between O. barthii and O. glumaepatula. To clarify phylogenetic relationships among AA genomes, whole-genome sequences obtained from different species were used to develop chloroplast INDEL markers. The INDEL patterns clearly showed multiple maternal origins of O. glumaepatula. The complicated origins have resulted in high genetic diversity in this species. In contrast, the Australian endemic species O. meridionalis tended to show narrower diversity than the other species. High variation in O. rufipogon, reconfirmed using the chloroplast INDELs, covered the variation in O. meridionalis and part of the variation in O. glumaepatula. Maternal lineages including O. barthii, O. longistaminata and the remainder of O. glumaepatula were phylogenetically close to each other and carried low genetic diversity. They were separated from independent lineages, suggesting that they had diverged from a single ancestral maternal lineage, but diverged later to keep gene flow within respective species, as SSR compositions suggested. Genetic relationships among AA genome species indicate how these species have evolved and become distributed across four continents. © 2016 Dove Medical Press Ltd. All rights reserved.
Hirano T.,Meijo University |
Bekhasut P.,Prachinburi Rice Research Center |
Sommut W.,Prachinburi Rice Research Center |
Zungsontiporn S.,Weed Science Group |
And 3 more authors.
Field Crops Research | Year: 2014
To compare growth responses of floating rice (FR) and deepwater rice (DWR) to severe flooding conditions, two FR varieties, Plai Ngahm Prachinburi and Pin Gaew 56, and two DWR varieties, Prachinburi 2 and Hawm Prachinburi (RD45), were grown in the floating rice field of Prachinburi Rice Research Center in Thailand in 2007 and 2008. The water depth in the research field exceeded 1. m from September to October in both 2007 and 2008. Although the plant length of the two DWR varieties increased at a slower rate than those of the FR varieties, the DWR varieties kept parts of their foliage above the water surface. However, the survival rates of the DWR varieties were lower than those of the FR varieties under these conditions. The rates of internode elongation of the DWR varieties were slower than those of water level rise, whereas those of the FR varieties were almost equal. Consequently the tops of the uppermost leaf sheath in the FR varieties were always above the water level. These results suggest that FR can regulate internode elongation in response to rising water level so as to keep the top of the uppermost leaf sheath above the water surface. © 2014 Elsevier B.V.