Frequency and fertility restoration efficiency of Rf3 and Rf4 genes in Indian rice

Identification of new parental lines is crucial for developing ecology‐specific hybrids with ideal agronomic performance. We screened a total of 570 different ecology‐specific Indian rice varieties for the presence of fertility restorer genes, Rf3 and Rf4 using tightly linked markers DRRM Rf3‐10 and RM6100, respectively. Among these varieties, 13% carried Rf3Rf3/Rf4Rf4, 31% carried rf3rf3/rf4rf4, 6% carried Rf3Rf3/rf4rf4 and remaining 50% carried Rf4Rf4/rf3rf3 allelic combinations. A mini set of 40 varieties with variable allelic combinations of fertility restorer genes were testcrossed with WA and Kalinga‐based CMS lines. All the 80 F₁s were evaluated for spikelet fertility and fertility restoration ability. Rf3Rf3/rf4rf4 genotypes mostly behaved as partial maintainers or partial restorers. In contrast, rf3rf3/Rf4Rf4 genotypes were partial or effective restorers. However, double dominant genotypes showed better fertility restoration than the genotypes containing Rf3 or Rf4 individually. Some of the genotypes showed unexpected restoration pattern implying occurrence of other fertility restorer(s) apart from Rf3 and Rf4. The perfect restorers and maintainers identified in this study can be directly used in hybrid rice breeding.     

Auxin synergists in the rooting of mango cuttings

Preplanting application of phenolic compounds, p-hydroxybenzoic acid p-coumaric acid and ferulic acid, in most cases promoted auxin-induced rooting on cuttings of mango, a difficult-to-root fruit plant. The ethylene-releasing chemical CEPA (ethrel, ethephon) also stimulated rooting in the presence of auxins. Synergism was more pronounced in the presence of IBA than with IAA. To a certain extent, root-promoting effects of auxins and non-auxin chemicals were related to the utilization of carbohydrate fractions from the region of root formation. Utilization of reserve polysaccharides assumed greater importance only during the root-development phase.     

The role of nickel on somatic embryogenesis in Setaria italica L. in vitro

Nickel (0.13, 0.25, 0.5, 1.0 and 1.5 mg/l) increased the efficiency of somatic embryogenesis in leaf base and mesocotyl derived calli of Setaria italica. A lower concentration of nickel in the culture media promoted long-term maintenance of embryogenic calli that regenerated into plantlets. The plants obtained from embryogenic calli grown on Ni-containing medium showed tolerance to nickel. The growth of embryogenic callus was the maximum at 1.5 mg/l as compared to a lower or a higher concentration of Ni. Use of nickel may help in the induction of high frequency somatic embryogenesis in Setaria italica. This revised version was published online in July 2006 with corrections to the Cover Date.     

Theileria infectivity ofHyalomma ticks in Haryana,India

Summary Theileria infection of Hyalomma ticks collected from three districts of Haryana was assessed in whole salivary glands by the methyl-green pyronin staining method. Of 1,662 ticks screened, 546 (32·8%) were found Theileria positive. Infection rate in 935 female ticks (36·9%) was more than that of 727 male ticks (27·6%). Density of Theileria infection (number of infected acini per infected tick) was also higher in female ticks.Theileria infection rate of ticks varied greatly in the three districts viz. only 12·0% in Rohtak, 25·8% in Hisar and 48·3% in Karnal. Per cent infection rate was high (63·7%) in ticks from indigenous cattle and low (18·6%) in those collected from buffaloes. However, the intensity of infection in infected ticks from cross-bred cattle was comparatively much higher. Frequency distribution ofTheileria positive acini in infected ticks revealed a low density of infection per infected tick. This points to the largely stable endemic situation prevailing in Haryana. Only a single salivary acinus was found infected in 16·6% of the infected ticks, about 70% had up to 10 infected acini while only about 10% had over 25 infected acini per tick. The masses in acini presumed to beTheileria were confirmed by demonstrating parasitic masses on staining one of a pair of salivary glands and inoculating the suspension of the other half of the gland into two cross-bred cow calves which developed clinical signs and lesions typical of theileriosis.

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Resumen Se determinó la infectividad theilérica de garraptasHyaloma colectadas en tres distritos de Haryana, examinando las glándulas salivares mediante el método de coloración de la pironina verde-metilo. De 1662 ácaros examinados, 546 (32·8%) se encontraron positivas a theileria. La frecuencia de infección en 935 hembras (36·9%) fue más alta que la encontrada en 727 machos (27·6%). El número de acinos infectados por garrapata infectada fue tambien superior en garrapatas hembras. La fracuencia de la infección theilérica vario en tres distritos. Se encontro el 12·0% en Rohtak, 25·8% en Hisar y 48·3% en Karnal. La frequencia de infección por ciento fue alta (63·7%) en garrapatas de ganado criollo y bajo (18·6%) en aquellas colectadas de búfalos. Sin embargo, la frecuencia de infección en garrapatas de ganado cruzado, fue comparativamente más alta. La frecuencia de distribución de acinos positivos a theileria en garrapatas infectadas, reveló una baja densidad de infección por garrapata infectada. Esto se?ala una situación endémica estable prevalente en Haryana. Solamente un acino salivar se encontro infectado en el 16·6% de gappapatas infectadas, cerca del 70·0% tuvo arriba de 10 acinos infectados, mientras que solamente et 10·0% tuvo sobre los 25 acinos infectados, por garrapata. Las masas de acinos presumiblemente de theileria, se confirmaron mediante la tinción de la glándula salivar e inoculando parte de ella en terneros cruzados, los cuales desarrollaron theileriosis.

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Résumé L’infection theilerienne desHyalomma récoltées dans 3 districts de l’Haryana a été examinée sur les glandes salivaires totales par la méthode de coloration au vert de méthyle-pyronine. Sur 1662 tiques, 546 (soit 32,8 p. 100) ont été trouvées positives pour lesTheileria. Le taux d’infection (36,9 p. 100) de 935 tiques femelles est supérieur à celui de 727 males (27,6 p. 100). La densité de l’infection parTheileria (nombre d’acini infectés par tique infectée) est plus grande chez les tiques femelles. Le taux d’infection des tiques varie considérablement selon le district: 12,0 p. 100 dans le Rohtak, 25,8 p. 100 dans l’Hisar et 48,3 p. 100 dans le Karnal. Il est élevé (63,7 p. 100) chez les tiques collectées sur du bétail indigène et bas sur celles prélevées sur des buffles (18,6 p. 100). Cependant, l’intensité de l’infection des tiques prélevées sur du bétail métis est comparativement plus grand. La fréquence de distribution des acini positifs pour lesTheileria chez les tiques infectées révèle une faible intensité d’infection par tique. Ceci montre la situation endémique stable existant dans l’Haryana. On n’a trouvé qu’un seul acinus infecté chez 16,6 p. 100 des tiques infectées; environ 70 p. 100 ont jusqu’à 10 acini infectés tandis que 10 p. 100 ont plus de 25 acini infectés. Les masses présentes dans les acini et présumées être desTheileria ont été confirmées être ces agents par coloration de l’une des paires de glandes salivaires et inoculation de l’autre à deux veaux métis qui ont developpé des signes cliniques et des lésions typiques de theileriose.

     

Identification of sex-specific DNA markers in betel vine (Piper betle L.)

The Random Amplified Polymorphic DNA (RAPD) technique was used to amplify DNA segments, with the objective of finding markers linked to sex determination in male and female plants of Piper betle L. Two bulks of DNA were made drawing one each from male and female, by pooling an equal volume of DNA samples from each group of individual contributing to the bulk analysis. Fifty different random decamer primers were screened with the two bulks to identify markers associated with sex expression of which only four primers were found to be associated with sex expression. These four primers were then tested with individual plant DNA samples where sex-associated RAPD markers were identified. A ~1,400 and ~850?bp fragment from the primer OPA04 and OPN 02 respectively was found to be present in all the male individuals and absent in all the female plants. In another primer, a ~980?bp amplification product from the primer OPC 06 was present only in the female individuals. A common primer OPA 08 showed both male and female specific markers of 650 and 1,200?bp respectively. Thus, the three male- specific RAPD markers OPA04₁₄₀₀, OPA08₆₅₀ and OPN02₈₅₀ and two female-specific markers OPA08₁₂₀₀ and OPC06₉₈₀ can reliably differentiate the male and female plants of P. betle L. Ploidy comparison also showed the differences in male and female plants.     

Antidiarrhoeal activity of Strychnos potatorum seed extract in rats

The antidiarrhoeal activity of the methanol extract of the dried seeds of Strychnos potatorum (MESP) has been evaluated out in rats using different models (castor oil-induced diarrhoea, effects on gastrointestinal motility and on PGE(2)-induced gastric enteropooling. MESP (100, 200 and 400 mg/kg, p.o.) significantly (P<0.001) inhibited the frequency of defaecation and reduced the wetness of faecal droppings in castor oil-induced diarrhoea, decreased the propulsion of charcoal meal through the gastrointestinal tract, and also reduced the PGE(2)-induced enteropooling.     

Comparison of Nutritional and Physicochemical Quality of Rice Under Organic and Standard Production Systems

Growing interest in sustainable agriculture has prompted this study aiming to evaluate nutritional content of rice grain produced from an organic production system. Here, we grew nine quality rice cultivars under organic methods in the wet and dry seasons, and the nutritional values, grain quality, and physiological parameters were compared with respective cultivars grown under the standard cultivation method (SCM). Obtained results revealed that the yield and plant height were lower, but tillering capacity was higher, in the organic field compared with the standard one. The organic crop showed significantly lower contents of protein and phytate compared with reference values under the SCM. Antioxidative capacity and its responsible phytochemicals such as phenolics, flavonoids, and γ‐oryzanol were also significantly higher under organic cultivation than under the SCM. Among physicochemical characteristics, apparent amylose content, gel consistency, and area and perimeter of grain were also higher in the organic crops, but hulling quality, milling quality, head rice recovery, and all other cooking qualities were at par. Higher crude oil and lower total protein content of rice bran were observed in the organic crop, but ash, fiber, and moisture contents did not vary significantly in these two cultivation systems.     

Characterization and pathogenicity studies of Vibrio parahaemolyticus isolated from diseased freshwater prawn, Macrobrachium rosenbergii (de Man)

Vibrio parahaemolyticus, an important pathogen of freshwater prawn, Macrobrachium rosenbergii causes high mortality. Four strains of V. parahaemolyticus were isolated from the gill, haepatopancreas, hemolymph and carapace of diseased prawn. The species were characterized based on biochemical and serological tests. On performing an antibiotic assay, these strains were found to be highly susceptible to cephalaxin, tetracycline and erythomycin. During the in vitro pathogenicity test, all the strains were found to be positive to the Congo red binding assay and to be haemolytic in nature, whereas an in vivo pathogenicity test revealed that 2 × 10⁹ CFUs mL^?1of bacteria induced disease symptoms such as black colouration on the carapace, red discolouration of the exoskeleton and loss of appendages within 6 days and 80% mortality. In histopathological studies, a prominent necrosis was seen in gill lamellae, and branchial arches were thickened at places due to hyperplasia and haemocytic infiltration. Hepatopancreatic tissue showed dilation of tubules, vacuolation of hepatocytes and marked necrosis in acinar cells. Development of an immunological technique for the detection and screening of V. parahaemolyticus infection and its treatment is highly important in freshwater prawn aquaculture.     

Differential chromium tolerance among eight mungbean cultivars grown in nutrient culture

Eight mungbean (Vigna radiata L.) cultivars were evaluated for their tolerance to different levels of chromium (Cr⁺⁶) (0, 24, 48, 96, 192, and 384 μM) in nutrient solutions at pH 6.8. Seeds were germinated and grown in the presence of chromium under controlled environmental conditions. Standard growth parameters such as root length, shoot length, root/shoot dry matter production, and root/shoot tolerance index were used as indicators of chromium toxicity. Measurements as early as 24 h after the beginning of the treatments did not yield consistent results. However, root measurements at 48, 72, and 96 h after the beginning of treatments yielded significant differences among the cultivars which were similar to field performance observations made for mungbean growing in chromium‐rich soils. The cultivars, TARM‐22 and K‐851 had enhanced root growth while PDM‐54, Sujata, TARM‐21, LGG‐407, and PDM‐116 showed a reverse trend in root growth in the presence of chromium. The root tolerance index (RTI) and the shoot tolerance index (STI) with respect to the cultivars TARM‐22 and K‐851 were high indicating their tolerance to chromium, while the cultivars PDM‐54 and Sujata showed a low RTI and STL Based on the growth parameters of the eight mungbean cultivars, they were ranked with respect of their tolerance to chromium as follows: TARM‐22>K‐851>Dhauli>PDM‐116>LGG‐407>TARM‐21> Sujata>PDM‐54. Therefore, the nutrient culture method was able to quickly screen the mungbean cultivars for their tolerance to chromium.