Diversity among melon (Cucumis melo L.) landraces from the Indo-Gangetic plains of India and their genetic relationship with USA melon cultivars

We report here the first broad genetic characterization of farmer-developed landraces of melon (Cucumis melo L.) from the Indo-Gangetic plains of India, an area overlooked in previous melon genetic diversity analyses of Indian melon germplasm. Eighty-eight landraces from three melon Groups in two subspecies (C. melo subsp. agrestis Momordica Group, and C. melo subsp. melo Cantalupensis Group and Reticulatus Group) were collected from the four agro-ecological regions (six sub-regions) of two northern states of the Indo-Gangetic plains of India, Uttar Pradesh and Uttarakhand. Significant differences were found among the landraces and eight USA Reticulatus Group reference cultivars for 18 plant and fruit traits: no. of primary branches per plant, days to marketable maturity, sex expression, fruit shape, flesh colour, netting, no. of fruit per plant, fruit weight, shelf life, total soluble solids (°Bx), ascorbic acid (mg/100 g), titratable acidity (%), fruit length and diameter, seed cavity length and diameter, flesh thickness, and resistance to Cucumber mosaic virus. The three melon groups differed significantly for 10 of the plant and fruit traits. Cantalupensis Group and Reticulatus Group accessions were andromonoecious, and the Momordica Group was monoecious. Neighbour-joining (NJ) tree and factorial correspondence analysis (FCA) of simple sequence repeat loci also revealed a high level of genetic variability in this germplasm. The 96 melon genotypes clustered into five groups in the NJ tree analysis: the 16 Indian Reticulatus Group accessions and eight USA reference cultivars formed a distinct group; and the 60 Cantalupensis Group accessions clustered in four other groups with the 12 Momordica Group accessions in a distinct subgroup of one of the Cantalupensis groups. The FCA plot largely confirmed the NJ tree with three distinct groups, one for each melon group. The close affinity of the Indian and USA Reticulatus melons was not unexpected, but it is not clear whether it was inherent in the group and maintained as Reticulatus melons moved from India through Central Asia and Europe to North America, or the result of recent intercrossing of Indian landraces with the USA-derived cultivars and selection for a broad range of Reticulatus type melons.     

Genetics of resistance to <Emphasis Type="Italic">Cucumber mosaic virus</Emphasis> in <Emphasis Type="Italic">Cucumis sativus</Emphasis> var. <Emphasis Type="Italic">hardwickii</Emphasis> R. Alef

The genetics of resistance to Cucumber mosaic virus (CMV) in Cucumis sativus var. hardwickii R. Alef, the wild progenitor of cultivated cucumber was assessed by challenge inoculation and by natural infection of CMV. Among the 31 genotypes of C. sativus var. hardwickii collected from 21 locations in India the lowest mean percent disease intensity (PDI) was recorded in IC-277048 (6.33%) while the highest PDI was observed in IC-331631 (75.33%). All the four cultivated varieties (DC-1, DC-2, CHC-1 and CHC-2) showed very high PDI and susceptible disease reaction. Based on mean PDI, 8 genotypes were categorized as resistant, 13 as moderately resistant, 9 as moderately susceptible and one as susceptible. A chi-square test of frequency distribution based on mean PDI in F₂ progenies of six resistant × susceptible crosses revealed monogenic recessive Mendelian ratio 1(R):3(S) to be the best fit. This monogenic recessive model was further confirmed by 1(R):1(S) ratio as the best fit for back cross with resistant parent and no fit for either 3:1 or 1:1 in the back cross with the susceptible parent. The results revealed that CMV resistance in C. sativus var. hardwickii was controlled by a single recessive gene. Considering the cross compatibility between C. sativus var. hardwickii and cultivated cucumber, the resistance trait can be easily transferred to cultivated species through simple backcross breeding.     

Replacing saline–sodic irrigation water with treated wastewater: effects on saturated hydraulic conductivity,slaking, and swelling

Irrigation with saline–sodic water imposes sodic conditions on the soil and reduces the soil’s productivity. We hypothesized that replacing saline–sodic irrigation water with lesser saline–sodic treated waste water (TWW), albeit with higher loads of organic matter and suspended solids, might help sodic soils regain their structure and hydraulic conductivity. We studied hydraulic conductivity (HC), aggregate stability and clay swelling of a soil from the Bet She’an Valley, Israel using samples taken from a non-cultivated field (control), and plots irrigated with TWW, saline–sodic Jordan River (JR) water, and moderately saline–sodic spring (SP) water. Soil samples were taken at the end of the irrigation season (autumn 2005) and at the end of the subsequent rainy season (spring 2006). In the HC and the aggregate stability determinations, for both sampling seasons, the TWW-irrigated samples gave significantly higher values than the SP- and JR-irrigated samples, but lower than the samples from the control plot. The autumn samples exhibited, generally, higher HC and lower swelling levels compared with the spring samples. Conversely, aggregate stability of the spring samples was higher than that of the autumn samples. These seasonal changes in the results of the three tests were associated with seasonal changes in the salinity and sodicity of the soils. Contributions from the Agricultural Research Organization, The Volcani Center, Bet-Dagan 50250, Israel. No. 601/2007 series.     

The disposition kinetics and residues of fenvalerate in tissues following a single dermal application to black bengal goats

The disposition kinetics of fenvalerate were studied in goats after dermal application of 100 ml of 0.25% (w/v) solution. The insecticide persisted in the blood for 72 h. The mean (±SEM) V _d(area) and apparent t _1/2 () were 9.92±1.44 L/kg and 17.51±2.65 h, while the AUC and Cl_B values were respectively 82.15±7.40 g h/ml and 0.56±0.05 L/(kg h). Four days after the dermal application, the highest concentration of fenvalerate residues was found in the adrenal gland, followed by the biceps muscle, omental fat, liver, kidney, lung and cerebrum in that order. Fenvalerate caused hyperglycaemia but had no effect on serum protein and cholesterol levels. Serum acetylcholinesterase activities were increased after 24 h but were below the initial values from 48 to 120 h.Abbreviations Ache acetylcholinestase - AUC total area under the blood insecticide concentration-versus-time curve - Cl_B total body clearance - GLC gas-liquid chromatography - t _1/2() apparent elimination half-life - V _d(area) apparent volume of insecticide distribution based on area method     

Soil loss tolerance values for different physiographic regions of Central India

In India, a single soil loss tolerance ( T ) value of 11.2 Mg/ha is by default used for formulating land restoration strategies for all soil types, climates and vegetation covers. However, this single 'T' value does not represent a true picture of soil loss tolerance under all land uses. The objective of our study was to develop adjusted ' T ' values for Central India using soil infiltration rate, bulk density, total organic carbon, erodibility and soil pH. Soil state was defined using a quantitative model involving different soil functions which were used to convert soil parameters to a 0 to 1 scale. The normalized values were then multiplied by appropriate weighing factors based on relative importance and sensitivity analysis of each indicator. Based on overall assessment, each soil mapping unit was categorized into soil groups I, II or III. A general guideline of USDA – Natural Resource Conservation Service (USDA-NRCS) was followed to calculate soil loss tolerance for each soil group using effective soil depth. Adjusted ' T ' values for Central India ranged from 2.5 to 12.5 Mg/ha compared with a default value of 11.2 Mg/ha. Use of these values for soil mapping units will improve conservation planning and assist with planning the development of sustainable agriculture.     

Antimicrobial activity of saponins from Acacia auriculiformis

Acaciaside A and B, two acylated bisglycoside saponins originally isolated from the funicles of Acacia auriculiformis, are known to have antihelminthic activity. Their antifungal and antibacterial activities were investigated. Complete inhibition of conidial germination of Aspergillus ochraceous and Curvularia lunata was recorded at 300 microg/ml or less whereas to inhibit the growth of Bacillus megaterium, Salmonella typhimurium and Pseudomonas aeruginosa 700 microg/ml or higher concentrations of the mixture was required. Two catabolic enzymes, phosphofructokinase and isocitrate dehydrogenase, responded differentially in fungi and bacteria against sublethal concentrations of the compound when assayed from their cell free extracts. An increased specific activity of the enzymes in bacteria and a decrease activity in fungi indicate a possible different mechanism of inhibition of saponins on the organisms tested.     

Metabolic responses of tea (<Emphasis Type="Italic">Camellia</Emphasis> sp.) to exogenous application of ascorbic acid

Effects of exogenous application of ascorbic acid on physiological and metabolic changes in tea were investigated in the present study. The highest improvement in yield was evident in response to regular application (a day after every harvest) of ascorbic acid at 600 ppm followed by 400 ppm. Foliar application of ascorbic acid (600 ppm) at regular intervals enhanced chlorophyll a and b contents besides a significant increase in total polyphenols and catechins when compared to the untreated control. Exogenous application of ascorbic acid at alternate harvesting rounds increased the activity of polyphenol oxidase whereas ascorbate peroxidase remained unchanged. An increase in phenylalanine ammonia lyase activity was noticed with foliar application of ascorbic acid irrespective of its concentrations. Theaflavins and thearubigins of made tea showed an increase when ascorbic acid was applied with 400 and 600 ppm at alternate intervals. The scores of brewed tea liquor characteristics, viz. infusion, color, strength, and briskness were higher even at the lower concentration of ascorbic acid treatment. Results suggest that foliar application of ascorbic acid (400 ppm) proved to be a useful measure to improve the yield, physiological attributes, and antioxidant properties of tea.     

Phenotypic and genetic characterization of Edwardsiella tarda isolated from pond sediments

The extent of genotypic and phenotypic diversity of Edwardsiella tarda isolated from pond sediment was assessed by SDS-PAGE, Plasmid Profiling and ERIC-PCR. SDS-PAGE of whole cell protein extracts reveals 20-23 discrete bands with molecular wt of 14-110 kDa. Several bands with molecular weight range of 38-83 kDa were present in all the isolates. Numerical analysis of protein electrophoregram delineated the isolates into four clusters. Two different types of plasmids having molecular mass of 23 kDa and 29 kDa were obtained by plasmid profiling. About 51% of the isolates carried both the plasmids. ERIC-PCR generates 3-7 bands with molecular mass of 14-1013 bp. Numerical analysis differentiated the ERIC pattern into 5 clusters at 60% similarly level. It was concluded that out of three methods ERIC-PCR was found to be more sensitive for intraspecific typing of E. tarda and can be used as a potential tool for epidemiological studies in the future.     

Estimation of (co)variance components and genetic parameters of greasy fleece weights in Muzaffarnagari sheep

Variance components and genetic parameters for greasy fleece weights of Muzaffarnagari sheep maintained at the Central Institute for Research on Goats, Makhdoom, Mathura, India, over a period of 29 years (1976 to 2004) were estimated by restricted maximum likelihood (REML), fitting six animal models including various combinations of maternal effects. Data on body weights at 6 (W6) and 12 months (W12) of age were also included in the study. Records of 2807 lambs descended from 160 rams and 1202 ewes were used for the study. Direct heritability estimates for fleece weight at 6 (FW6) and 12 months of age (FW12), and total fleece weights up to 1 year of age (TFW) were 0.14, 0.16 and 0.25, respectively. Maternal genetic and permanent environmental effects did not significantly influence any of the traits under study. Genetic correlations among fleece weights and body weights were obtained from multivariate analyses. Direct genetic correlations of FW6 with W6 and W12 were relatively large, ranging from 0.61 to 0.67, but only moderate genetic correlations existed between FW12 and W6 (0.39) and between FW12 and W12 (0.49). The genetic correlation between FW6 and FW12 was very high (0.95), but the corresponding phenotypic correlation was much lower (0.28). Heritability estimates for all traits were at least 0.15, indicating that there is potential for their improvement by selection. The moderate to high positive genetic correlations between fleece weights and body weights at 6 and 12 months of age suggest that some of the genetic factors that influence animal growth also influence wool growth. Thus selection to improve the body weights or fleece weights at 6 months of age will also result in genetic improvement of fleece weights at subsequent stages of growth.