Archive

28 March 2015, Volume 22 Issue 2 Previous Issue    Next Issue
---
Orginal Article


For Selected:

Download Citations EndNote Ris BibTeX

Toggle Thumbnails

Orginal Article

Select

Characterization of Myanmar Paw San Hmwe Accessions Using Functional Genetic Markers Swar Oo Kyaw, Kongjaimun Alisa, Khanthong Srisawat, Yi Myint, Tin Myint Tin, Korinsak Siriporn, Lanceras Siangliw Jonaliza, Myo Myint Khin, Vanavichit Apichart, Malumpong Chanate, Toojinda Theerayut 2015, 22(2): 53-64.  DOI: 10.1016/S1672-6308(14)60285-7 Abstract ( )   HTML ( )   PDF (1159KB) ( )   Paw San Hmwe (PSM) rice has been cultivated in many areas of Myanmar for a long time. Strong aroma, good taste and its elongation during cooking are the key characteristics of PSM rice. Thirty-one PSM accessions were genotypically characterized, and their physical grain and cooking quality traits were studied. We used specific gene markers associated with aroma, apparent amylose content (AAC) and alkali spreading value to determine the alleles carried by different PSM accessions. The results revealed that six PSM accessions (PSM10, PSM12, PSM13, PSM21, PSM22 and PSM30) had a 3-bp insertion in Os2AP gene. Gel consistency (GC) allele was predominant among the PSM accessions for gelatinization temperature (GT), however, the phenotype observed was between low and intermediate GT because of the combination of the GC allele with the presence of low GT allele at heterozygous state from the other loci of the SSIIa gene. Intermediate to high AAC was observed among the PSM accessions corresponding to the haplotype identified for the single nucleotide polymorphism G/T and the (CT)n repeat in the Wx gene. The characterization and grouping data of PSM accessions posted benefits to Myanmar seed banks, and our results will help in maintaining the integrity of PSM rice variety.

Select

Functional Marker Development and Effect Analysis of Grain Size Gene GW2 in Extreme Grain Size Germplasm in Rice Ya-dong Zhang, Jia Zheng, Yan-li Liang, Chun-fang Zhao, Tao Chen, Qing-yong Zhao, Zhen Zhu, Li-hui Zhou, Shu Yao, Ling Zhao, Xing Yu, Cai-lin Wang 2015, 22(2): 65-70.  DOI: 10.1016/S1672-6308(14)60280-8 Abstract ( )   HTML ( )   PDF (6497KB) ( )   GW2 is an important gene that regulates grain width and weight. We used cDNA clone to obtain the sequences of GW2 from large- and small-grained rice varieties, TD70 and Kasalath, respectively. Then, we developed a dCAPS (derived cleaved amplified polymorphic sequence) marker on the basis of the sequence difference between functional and nonfunctional GW2 genes to analyze the genotypes and phenotypes of recombinant inbred lines. Results showed that the sequence of GW2TD70 had a single nucleotide deletion at site 316 that generates a termination codon. This codon terminated the GW2 protein in advance. By contrast, the sequence of GW2Kasalath encoded an intact protein. A novel dCAPS marker was designed in accordance with a base A deletion at site 316 of the sequence. After the PCR product was digested by ApoI, TD70 showed 21 and 30 bp fragments, and Kasalath showed a 51 bp fragment. Up to 82 lines contained GW2TD70, and 158 lines contained GW2Kasalath. The lines that contained TD70 alleles displayed substantial increases in width and 1000-grain weight. This result suggested that GW2 played a critical role in rice breeding.

Select

Performance of Four Rice Cultivars Transplanted Monthly over Full Year under Irrigated Conditions in Tanzania Sekiya Nobuhito, Cyril Shayo Aristarick, Kaozya Jacob Mathew, Oizumi Nobuaki, Tomitaka Motonori, Araki Hideki 2015, 22(2): 71-80.  DOI: 10.1016/S1672-6308(14)60283-3 Abstract ( )   HTML ( )   PDF (912KB) ( )   In Tanzania, the phenology and seasonal variations of the yields of different rice cultivars have rarely been studied, especially under fully-irrigated conditions. A trial was conducted to identify the most suitable calendar for rice production in Tanzania under fully-irrigated conditions. Four popular rice cultivars, NERICA1, Wahiwahi, IR64 and TXD306, were transplanted monthly from January to December 2011. The four cultivars recorded similarly higher or lower yields than the annual means when transplanted in July (0.50-0.57 kg/m2) and April (0.07-0.31 kg/m2). A yield-ranking analysis showed that plants transplanted in July was the most productive while those transplanted in April was the least productive, and also revealed a yield-seasonality for irrigated rice in Tanzania, a low-yield season (April-May), a high-yield season (June-August), and an unstable-yield season (September-March). These yield seasons would appear to be closely linked to seasonal temperature variations. When transplanted in April-May, plants were exposed to very low temperatures between panicle initiation and flowering, apparently reducing yield through cold-induced sterility. Those transplanted in June-August prolonged their growth under relatively low temperatures and increased yield through increasing biomass production. In September-March, yield levels varied greatly due to the shortened phenological growth durations at higher temperatures. We conclude that under fully-irrigated conditions in Tanzania, rice should be transplanted in July to ensure the maximum production and yield stability. The yield-seasonality suggests that implementing measures to protect plants from low and high temperature stress at critical phenological stages may allow year-round rice production under fully-irrigated conditions in Tanzania.

Select

Heterosis Expression of Hybrid Rice in Natural- and Short-Day Length Conditions Zhi-yuan Huang, Bing-ran Zhao, Qi-ming Lv, Xi-qin Fu, Ye-yun Xin, Long-ping Yuan 2015, 22(2): 81-88.  DOI: 10.1016/S1672-6308(14)60286-9 Abstract ( )   HTML ( )   PDF (532KB) ( )   Development of hybrid rice is an important strategy to increase yields of irrigated rice in China. Day length is a highly important environmental factor for hybrid rice adaptability, productivity and quality. Heterosis of hybrid rice has been utilized under natural- (long) day length conditions in the middle and lower reaches plain of Yangtze River Valley in China for a long time. However, whether the hybrid rice can show heterosis under short-day length conditions is unknown. In this study, we analyzed plant height, grain number per panicle, and other yield related traits of hybrid rice Liangyoupeijiu (LYP9) and its parents (Pei’ai 64S and 93-11) under natural- and short-day length conditions and compared the respective heterosis. Results showed that earlier heading, reduced plant height, and reduced grain number per panicle were found in these three varieties under short-day length conditions relative to those under natural-day length conditions. In either natural- or short-day length conditions, heterosis of LYP9 was mainly displayed in grain number per panicle and plant height. This study may help in breeding and selecting suitable hybrid rice for different regions with natural- or short-day length.

Select

Probit Analysis of Carbamate-Pesticide-Toxicity at Soil-Water Interface to N2-Fixing Cyanobacterium Cylindrospermum sp N. Padhy Rabindra, Rath Shakti 2015, 22(2): 89-98.  DOI: 10.1016/S1672-6308(14)60281-X Abstract ( )   HTML ( )   PDF (495KB) ( )   Toxicity-data of two carbamate insecticides, carbaryl and carbofuran, and three fungicides, ziram, zineb and mancozeb with rice-field N2-fixing cyanobacterium Cylindrospermum sp., obtained by in vitro growth and at soil-water interface, were analyzed by the probit method. Growth enhancing concentration, no-observed effective concentration, minimum inhibitory concentration, the highest permissive concentration and lethal concentration100 (LC100) were determined experimentally. The LC50 values of carbaryl, carbofuran, ziram, zineb and mancozeb in N2-fixing liquid medium were 56.2, 588.8, 0.07, 4.2 and 3.4 µg/mL, respectively, whereas the corresponding LC100 values were 100.0, 1500.0, 0.17, 25.0 and 9.0 µg/mL, respectively. The LC50 values of these pesticides in succession in N2-fixing agar medium were 44.7, 239.9, 0.07, 1.8 and 2.3 µg/mL, respectively, whereas the corresponding LC100 values were 100.0, 600.0, 0.17, 10.0 and 7.0 µg/mL, respectively. Similar results with nitrate supplemented liquid and agar media indicated that nitrate supplementation had toxicity reducing effect. The LC50 and LC100 values of toxicity in the N2-fixing liquid medium at soil-water interface were 91.2 and 200.0 µg/mL for carbaryl, 2 317 and 6 000 µg/mL for carbofuran, 0.15 and 0.50 µg/mL for ziram, 16.4 and 50.0 µg/mL for zineb, and 7.2 and 25.0 µg/mL for mancozeb, respectively. Each LC100 value at soil-water interface with a pesticide was significantly higher than its corresponding LC100 value at liquid/agar media. It can be concluded that, under the N2-fixing conditions, the cyanobacterium tolerated higher levels of each pesticide at soil-water interface.