Archive

28 May 2015, Volume 22 Issue 3 Previous Issue    Next Issue
---
Orginal Article


For Selected:

Download Citations EndNote Ris BibTeX

Toggle Thumbnails

Orginal Article

Select

Genetic Diversity and Population Structure in Landraces and Improved Rice Varieties from India D. Kumbhar Shailesh, L. Kulwal Pawan, V. Patil Jagannath, D. Sarawate Chandrakant, P. Gaikwad Anil, S. Jadhav Ashok 2015, 22(3): 99-107.  DOI: 10.1016/S1672-6308(14)60287-0 Abstract ( )   HTML ( )   PDF (86502KB) ( )   A set of 50 rice genotypes comprising landraces, local selections, and improved varieties were characterized using simple sequence repeat (SSR) and inter simple sequence repeat (ISSR) markers to study genetic diversity and population structure. Following unweighted pair group method with arithmetic mean based clustering using binary data of polymorphic markers, the genotypes were grouped into 5 clusters and 11 sub-clusters, whereas population structure analysis separated 50 rice genotypes into 5 sub-populations. Grouping of rice genotypes showed better resemblance with the pedigree information of the genotypes. Both genetic diversity and population structure analysis separated majority of the improved varieties from landraces and local selections. Some of the SSR markers amplified unique alleles which were specific to a particular genotype and could distinguish them from the rest. The results indicate that these rice genotypes exhibit a higher genetic diversity and can be very useful in rice improvement program.

Select

Quantitative Trait Locus Analysis for Rice Yield Traits under Two Nitrogen Levels Yue Feng, Rong-rong Zhai, Ze-chuan Lin, Li-yong Cao, Xing-hua Wei, Shi-hua Cheng 2015, 22(3): 108-115.  DOI: 10.1016/S1672-6308(14)60288-2 Abstract ( )   HTML ( )   PDF (752KB) ( )   A recombinant inbred line population derived from a super hybrid rice Xieyou 9308 (Xieqingzao B/Zhonghui 9308) and its genetic linkage map were used to detect quantitative trait loci (QTLs) for rice yield traits under the low and normal nitrogen (N) levels. A total of 52 QTLs for yield traits distributed in 27 regions on 9 chromosomes were detected, with each QTL explaining 4.93%-26.73% of the phenotypic variation. Eleven QTLs were simultaneously detected under the two levels, and 30 different QTLs were detected under the two N levels, thereby suggesting that the genetic bases controlling rice growth under the low and normal N levels were different. QTLs for number of panicles per plant, number of spikelets per panicle, number of filled grains per panicle, and grain density per panicle under the two N levels were detected in the RM135-RM168 interval on chromosome 3. QTLs for number of spikelets per panicle and number of filled grains per panicle under the two N levels, as well as number of panicles per plant and grain density per panicle, under the low N level, were detected in the RM5556-RM310 interval on chromosome 8. The above described QTLs shared similar regions with previously reported QTLs for rice N recycling.

Select

Male Parent Plays More Important Role in Heat Tolerance in Three-Line Hybrid Rice Guan-fu Fu, Cai-xia Zhang, Yong-jie Yang, Jie Xiong, Xue-qin Yang, Xiu-fu Zhang, Qian-yu Jin, Long-xing Tao 2015, 22(3): 116-122.  DOI: 10.1016/S1672-6308(14)60284-5 Abstract ( )   HTML ( )   PDF (1585KB) ( )   Ten F1 combinations with their male and female parents were employed to evaluate their heat tolerance during the flowering and early grain filling stages. The rice plants were subjected to heat stress (39 °C-43 °C) for 1-15 d during flowering. Based on the heat stress index, heat tolerance was only observed in the F1 combinations H2 (K22A × R207), H3 (Bobai A × R207) and H4 (Bobai A × Minghui 63), whereas the others received above 0.5000 of heat stress index. Both parents of the tolerant combination (heat-tolerant × heat-tolerant) possessed heat tolerance, whereas the susceptible combinations were crossed by heat-tolerant (sterile lines) × heat-susceptible (restorer lines), heat-susceptible × heat-tolerant, or heat-susceptible × heat-susceptible parents. This result indicated that heat tolerance in rice was controlled by recessive genes. Thus, both parents should possess high temperature tolerance to develop heat-tolerant F1 combinations. Furthermore, the heat stress index of F1 combinations was significantly correlated with the heat stress index of restorer lines but not with the heat stress index of maintainer lines. This result suggested that male parents play a more important role in heat-tolerant combinations than female parents. Therefore, the heat susceptibility of the hybrid rice in China is mainly due to the wide application of low-heat-tolerant restorer lines with high yield in three-line hybrid rice breeding.

Select

Different Aluminum Tolerance among Indica, Japonica and Hybrid Rice Varieties Chang Shu, Jing-hao Wu, Gao-ling Shi, Lai-qing Lou, Jun-xia Deng, Jian-lin Wan, Qing-sheng Cai 2015, 22(3): 123-131.  DOI: 10.1016/S1672-6308(14)60294-8 Abstract ( )   HTML ( )   PDF (41643KB) ( )   Hydroponic cultures were conducted to compare the aluminum (Al) tolerance among different rice (Oryza sativa L.) varieties, including indica, japonica and their hybrids. The results showed that the root growth of rice plant was inhibited in different degrees among Al treated varieties. The Al tolerance observed through relative root elongation indicated that five japonica varieties including Longjing 9, Dharial, LGC 1, Ribenyou and Koshihikari were relatively more tolerant than indica varieties. Most indica varieties in this study, such as Aus 373 and 9311 (awnless), were sensitive to Al toxicity. The Al tolerance of most progenies from japonica × indica or indica × japonica crosses was constantly consistent with indica parents. The differences of Al tolerance among Longjing 9 (japonica), Yangdao 6 (indica) and Wuyunjing 7 (japonica) were studied. Biomass and the malondial-dehyde content of Yangdao 6 under Al exposure decreased and increased, respectively, while there was no significant effect on those of Longjing 9 and Wuyunjing 7. Remarkable reduction of root activities was observed in all these three rice varieties. Significantly higher Al content in roots was found in Yangdao 6 compared to Longjing 9 or Wuyunjing 7.

Select

In-vitro vs in-vivo Inoculation: Screening for Resistance of Australian Rice Genotypes Against Blast Fungus Challagulla Vineela, Bhattarai Surya, J. Midmore David 2015, 22(3): 132-137.  DOI: 10.1016/S1672-6308(14)60292-4 Abstract ( )   HTML ( )   PDF (795KB) ( )   To assist with rapid screening for rice blast resistance as a precursor in a breeding program, the susceptibility to rice blast of 13 rice genotypes from Australia was evaluated in May to June 2013 using three distinct inoculation methods (spot, filter paper and standard methods) at seedling, vegetative and reproductive stages. The results revealed that the spot and filter paper inoculation methods were successful in discerning susceptibility to the rice blast disease (P ≤ 0.05). Disease susceptibility declined significantly from the vegetative to reproductive stages. The standard method was conducted at three different stages for pot plants grown inside the mist house. However, low temperatures did not produce disease symptoms except in a few genotypes. Among the 13 rice genotypes screened, AAT9 expressed a highly resistant response, and AAT4, AAT6, AAT10, AAT11, AAT13, AAT17 and AAT18 expressed resistance at various stages. The results will be useful for selecting elite genotypes for disease tolerance where rice blast is prevalent. In addition, the resistant genotypes can serve as a gene pool used in breeding programmes to develop new resistant genotypes.

Select

Biocultural Diversity of Sarangani Province, Philippines: An Ethno-Ecological Analysis Lasalita Zapico Florence, Hazel Aguilar Catherine, Abistano Angelie, Carino Turner Josephine, Jacinto Reyes Lolymar 2015, 22(3): 138-146.  DOI: 10.1016/S1672-6308(14)60290-0 Abstract ( )   HTML ( )   PDF (1956KB) ( )   This paper discussed effects of lowland-associated influences on upland ecology, food security and biocultural diversity in the Sarangani farming communities of the Philippines. In the uplands of Sarangani Province, the conservation of traditional rice varieties, the centrality of rice in tribal life, and the continued observance of planting rituals attest to its cultural significance and convey a common desire for cultural preservation and community solidarity. Economic and socio-political pressures had transformed tribal communities, although vestiges of traditional farming systems are still being practiced in remote sitios (villages). Changing land use patterns had also resulted in shrinking farm sizes and consequently in food insecurity in the Sarangani uplands. Extractive industries (i.e. logging, mining and charcoal making) and swidden farming were observed to cause widespread environmental degradation, while modern agriculture had undermined the capacity of indigenous peoples to survive because of their complete dependence on lands and resources. With the reality that cultural and biological diversities are inextricably linked, trans-disciplinary strategies coupling indigenous knowledge systems with scientific knowledge should, therefore, be instituted to save the Sarangani upland ecosystem, the indigenous peoples and their tribal resources.