28 September 2016, Volume 23 Issue 5 Previous Issue    Next Issue

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    Orginal Article
    Informative ISSR Markers Help Identify Genetically Distinct Accessions of Oryza rufipogon in Yield Improvement
    Haritha G., Sudhakar T., Chandra D., Ram T., Divya B., Sarla N.
    2016, 23(5): 225-241.  DOI: 10.1016/j.rsci.2016.08.001
    Abstract ( )   HTML ( )   PDF (1055KB) ( )  

    Inter simple sequence repeat (ISSR) polymorphism was used to determine genetic diversity and phylogenetic relationships in 90 genotypes of wild and cultivated species of Oryza from different geographical regions of the world. In all the 17 primers used in ISSR-PCR, a total of 11 464 bands were amplified at 253 band positions/loci. The primer UBC-809 amplified the maximum bands (1 059) at 21 band positions. UBC-810 and UBC-835 amplified the minimum of 391 bands each at 7 and 14 band positions, respectively. The mean polymorphism information content ranged from 0.44 to 0.84 and resolving power ranged from 8.69 to 23.53. Un-weighted pair group method with arithmetic mean dendrogram and population structure based on the 17 primers separated all genotypes into 4 major clusters with a genetic similarity of 53%-100%. The first two clusters consisted of 30 O. rufipogon accessions each. In the third cluster, O. nivara and O. longistaminata grouped as one sub-cluster and all other O. nivara accessions and cultivars grouped as another sub-cluster. The fourth cluster had only five O. rufipogon accessions which can be a source of new genes. Four sub-populations were identified within O. rufipogon and two sub-populations within O. nivara at K = 7. A subset of six primers with high resolving power values were the most informative and grouped all genotypes almost similarly as the 17 primers did. Use of these six highly informative primers in ISSR-PCR is a cost effective and robust method for assessing genetic diversity in large germplasm collections of wild rice species.

    Seed Priming with Beta-Amino Butyric Acid Improves Abiotic Stress Tolerance in Rice Seedlings
    Chandran Jisha Kolothodi, Thomas Puthur Jos
    2016, 23(5): 242-254.  DOI: 10.1016/j.rsci.2016.08.002
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    We studied the influence of seed priming with beta-amino butyric acid (BABA) on the growth, physiological and biochemical parameters of seedlings with varied abiotic stress tolerance, which were raised and grown under unstressed and stressed (NaCl/PEG-6000) conditions. Under stressed conditions, the growth of rice seedlings was less when compared to control plants. After BABA priming, the seedling growth increased both under unstressed and stressed conditions as compared to the respective controls. BABA priming of rice seeds caused increase in the photosynthetic pigment content of the leaves, modified the chlorophyll a fluorescence related parameters and also enhanced the photosystem activities of seedlings when compared to their respective non-primed controls. BABA priming also caused increased mitochondrial activities of the rice seedlings. Moreover, BABA priming significantly reduced malondialdehyde content in the seedlings and also resulted in accumulation of proline especially in the NaCl tolerant variety Vyttila 6. BABA seed priming also enhanced the activity of nitrate reductase enzyme and activities of antioxidant enzymes like guaiacol peroxidase and superoxide dismutase. The presence of BABA was detected by high performance thin layer chromatography analysis in the rice seeds whereas in the seedlings it was not detected. Thus, it can be inferred that the seed priming effect of BABA mainly occurred within the seeds, which was further carried to the seedlings. It is concluded that BABA priming of seeds improved the drought and salinity stress tolerance of all the three rice varieties and it was significantly evident in the drought tolerant variety Vaisakh and NaCl tolerant variety Vyttila 6, when compared to the stress sensitive variety Neeraja.

    Transformation of Sucrose to Starch and Protein in Rice Leaves and Grains under Two Establishment Methods
    Kumari Manisha, Asthir Bavita
    2016, 23(5): 255-265.  DOI: 10.1016/j.rsci.2016.08.003
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    Six rice varieties, PR120, PR116, FengAiZan, PR115, PAU201 and Punjab Mehak 1 were raised under aerobic and transplanting conditions to assess the effects of planting conditions on sucrose metabolising enzymes in relation to the transformation of free sugars to starch and protein in flag leaves and grains. Activities of sucrose synthase, sucrose phosphate synthase and acid invertase increased till flowering stage in leaves and mid-milky stage (14 d after flowering) in grains and thereafter declined in concomitant with the contents of reducing sugar. Under aerobic conditions, the activities of acid invertase and sucrose synthase (cleavage) significantly decreased in conjunction with the decrease in non-reducing sugars and starch content in all the varieties. Disruption of starch biosynthesis under the influence of aerobic conditions in both leaves and grains and the higher build up of sugars possibly resulted in their favoured utilization in nitrogen metabolism. FengAiZan, PR115 and PR120 maintained higher levels of sucrose synthase enzymes in grains and leaves and contents of metabolites (amino acid, protein and non-reducing sugar) under aerobic conditions, while PR116, Punjab Mehak 1 and PAU201 performed better under transplanting conditions, thus showing their adaptation to environmental stress. Yield gap between aerobic and transplanting rice is attributed primarily to the difference in sink activity and strength. Overall, it appear that up-regulation of sucrose synthase (synthesis) and sucrose phosphate synthase under aerobic conditions might be responsible in enhancing growth and productivity of rice varieties.

    Development of Hybrid Rice Variety FY7206 with Blast Resistance Gene Pid3 and Cold Tolerance Gene Ctb1
    Hong-guang Xie, Jia-huang Jiang, Yan-mei Zheng, Yong-sheng Zhu, Fang-xi Wu, Xi Luo, Qiu-hua Cai, Jian-fu Zhang, Hua-an Xie
    2016, 23(5): 266-273.  DOI: 10.1016/j.rsci.2016.08.004
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    Hybrid rice Fanyou 7206 (FY7206), derived from the cross between a sterile line Fanyuan A and a restorer line Fuhui 7206, was bred by the Rice Research Institute, Fujian Academy of Agricultural Sciences, China. FY7206 was characterized by moderate blast resistance, cold tolerance, as well as wide adaptability, and high yields. The blast resistance results indicated that the frequencies of blast races in race B, race C and the total resistance frequency for FY7206 were 95.5%, 100.0% and 97.2%, respectively. The disease resistance results showed that the leaf blast grade for FY7206 was level 1 and panicle blast was level 5. The indoor spray results indicated that FY7206 was resistant to 11 isolates of Magnorpathe oryzae. The blast resistance of FY7206 might be derived from the high expression of blast resistance gene Pid3. The results for simulated cold resistance in an artificial climate chamber indicated that the cold tolerance for FY7206 was moderate at the booting and flowering stages. The cold tolerance results also indicated that FY7206 could be tolerant to temperatures as low as 10 °C at the seedling stage. The qRT-PCR results showed that the expression of cold tolerance gene Ctb1 in FY7206 was relatively high. These results suggested that FY7206 is a hybrid indica rice variety with good comprehensive characteristics, including blast resistance and cold tolerance.

    Effects of Dry-Milling and Wet-Milling on Chemical, Physical and Gelatinization Properties of Rice Flour
    Leewatchararongjaroen Jitranut, Anuntagool Jirarat
    2016, 23(5): 274-281.  DOI: 10.1016/j.rsci.2016.08.005
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    Rice flour from nine varieties, subjected to dry- and wet-milling processes, was determined for its physical and chemical properties. The results revealed that milling method had an effect on properties of flour. Wet-milling process resulted in flour with significantly lower protein and ash contents and higher carbohydrate content. Wet-milled flour also tended to have lower lipid content and higher amylose content. In addition, wet-milled rice flour contained granules with smaller average size compared to dry-milled samples. Swelling power at 90 °C of wet-milled samples was higher while solubility was significantly lower than those of dry-milled flour. Dry milling process caused the destruction of the crystalline structure and yielded flour with lower crystallinity compared to wet-milling process, which resulted in significantly lower gelatinization enthalpy.

    Effects of Varieties and Cooking Methods on Physical and Chemical Characteristics of Cooked Rice
    Indriyani Syafutri Merynda, Pratama Filli, Syaiful Friska, Faizal Achmad
    2016, 23(5): 282-286.  DOI: 10.1016/j.rsci.2016.08.006
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    To analyze the effect of different lowland rice varieties and different cooking methods on physical and chemical characteristics of cooked rice. A factorial randomized block design with two factors was used and each combination of the factors was repeated three times. The first factor was rice variety (Ciherang and Ciliwung) and the second factor was the cooking method (stovetop, boiling and steaming, and rice cooker). Results showed that Ciherang and Ciliwung varieties were classified into slender grain rice type with yellow-red color. The amylose content of Ciherang was classified as moderate, while the amylose content of Ciliwung classified as low. The most abundant amino acid contained in Ciherang and Ciliwung varieties was glutamic acid. Statistical analysis showed that cooking method had significant effects on texture, lightness, chroma, hue and moisture content of cooked rice. Rice cooked with liwet method had the lowest texture value, lowest lightness value, highest chroma value, and highest moisture content.