Characterization of stem rust resistance in old tetraploid wheat landraces from the Watkins collection

Stem rust is one of the important diseases of tetraploid wheats worldwide. One hundred and five landraces from the Watkins collection were assessed for seedling and adult plant stem rust response variation. Seedling resistance genes Sr8a, Sr8b, Sr9e, Sr9g, Sr12, Sr13, Sr17 and Sr23 were postulated in 28 genotypes using Australian and Indian Puccinia graminis f. sp. tritici pathotypes. Four genotypes possessed either uncharacterized seedling stem rust resistance gene(s) or combinations of known stem rust resistance genes with compensating avirulences among pathotypes used. Adult plant stem rust response assessments were made on 73 seedling susceptible genotypes in Australia and Ethiopia. Adult plant stem rust responses varied from 1 (very resistant) to 7 (moderately susceptible) on a 1–9 scale. The Ethiopian nursery was exposed to Ug99 (TTKSK) and JRCQC (virulent on Sr9e and Sr13). Some genotypes that exhibited high responses in Australia were scored low in Ethiopia. These results demonstrated the effectiveness of some resistance gene(s) that were ineffective in Australia. The opposite trend was also noted. Over 50 % genotypes exhibited commercially acceptable rust responses varying between 2 and 5 across sites and years. Genotyping with the Sr2-linked molecular marker csSr2 did not detect Sr2 in any of the genotypes. The marker gwm533 however detected the presence of Sr2 in eight genotypes. Stem rust resistant genotypes that carried varying levels of APR could carry new genes. Genetic analysis and deployment of these uncharacterized sources of seedling and APR in new cultivars will ensure durable stem rust control through increased diversity.     

Seed characteristics and nutrient composition of selected beans (Phaseolus vulgaris L.) with different ozone tolerance

Ozone sensitivity, nutritional quality, seed characteristics, and growth habit of beans (Phaseolus vulgaris L.) were evaluated in two seperate experiments. In the first experiment the data showed a significant variation among 34 bean accessions for ozone sensitivity following acute exposure of 18-day-old plants to 0.6 µl/l O₃ for 2 hours under environmentally controlled greenhouse conditions. PI-163579, PI-169735, PI-171790, PI-176684, PI-201374, PI-310711, PI-345576, PI-370569, PI-379435, and PI-414831 were identified as tolerant to acute ozone exposures. Protein, oil, starch, sugar, and ash contents in the seed of selected germplasm were determined and no correlation was found between these components and ozone sensitivity. Seed size and growth habit varied considerably among the 34 accessions but were not correlated to ozone sensitivity. In a second experiment, ten accessions, selected from the tolerant ones identified in the first experiment, were subjected to chronic ozone exposure in open-top chambers at 0.04 and 0.08 µl/l concentrations for 7 hours/day 44 days after transplanting. Based on foliar injury and yield reductions, only PI-370569 and PI-414831 were tolerant to prolonged ozone exposure (0.08 µl/l). A significant positive correlation (r=0.83) existed between foliar injury rating from chronic treatments involving 0.04 and 0.08 µl O₃/l and acute exposure (0.6 µl O₃/1/2 hours). The data indicated that acute ozone exposure can be used to initially screen a large number of bean accessions, however, this is an imperfect indicator of ozone sensitivity with chronic exposure.Agricultural Research Station Journal Article Series, No. 191. The use of any trade name varieties and/or vendors does not imply the exclusion of other products or vendors that may also suitable.     

1,2,4-Triazolyl functionalized allyl sulfide with antifungal potential for the control of Fusarium fujikuroi causing foot rot of rice

European Journal of Plant Pathology - The present study focuses on antifungal potential of 1,2,4-triazole derivatives of allyl sulfides. The antifungal potential of synthesized...     

Diversification of maize (Zea mays L.) through teosinte (Zea mays subsp. parviglumis Iltis & Doebley) allelic

Genetic Resources and Crop Evolution - Zea mays ssp. parviglumis is the progenitor of maize and assume to have tolerance against various biotic and abiotic stresses. It...     

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.     

Molecular characterization and variability analysis of <Emphasis Type="Italic">Apple scar skin viroid</Emphasis> in India

Apple scar skin viroid (ASSVd) infection is a major limitation to apple fruit quality and causes huge economic losses. In surveys of apple orchards in the northern Indian state of Himachal Pradesh, fruits with dappling symptoms were noticed. ASSVd was detected from these fruits and molecularly characterized. Ten clones from three isolates were sequenced, of which seven were new sequence variants of ASSVd. The clones had significant sequence variability (94–100%) with each other. Variability was more common in the pathogenic domain of the viroid genome. Four of the clones were 330 nucleotides (nt) long, and the other six had an additional nucleotide. Phylogenetic analysis showed close affinity of the present isolates with some Chinese and Korean isolates. The study reports seven new variants of ASSVd and also provides the first molecular evidence of viroid infection (ASSVd) in apple in India.     

Changes in skin and rectal temperature in lactating buffaloes provided with showers and wallowing during hot-dry season

Twelve Murrah buffaloes in second or third parity during early lactation (50–70 days) were selected from the Institute’s herd. All the buffaloes were kept under loose housing system and were provided ad lib green maize fodder and water to drink during 30 days experiment during the month of August- September. The buffaloes were divided into two groups of six each. Showering group (SG) buffaloes were kept under water showers from 11:00 a.m. to 4:00 p.m., while wallowing group (WG) buffaloes were allowed to wallow in a water pond during the same time. Physiological responses viz. rectal temperature (RT), respiration rate (RR), pulse rate (PR) and skin temperature (ST) were recorded before (8.00 a.m.) and after (4.00 p.m.) showers or wallowing. Skin temperature at different sites i.e. trunk, forehead, udder, udder vein, and neck regions was measured. Skin and rectal temperature of both the groups were non significant in morning but varied (P < 0.01) in the evening. Skin temperature measured at all the sites was significantly lower (P < 0.01) in wallowing buffaloes than the showering group. Further, skin temperature of neck, head, udder, udder vein and RT varied (P < 0.01) in SG and WG buffaloes during periods of study. The significant changes in all the parameters of study further support the evidence on effective cooling of skin by wallowing in comparison to water showers. The correlation data indicated a positive correlation of maximum air temperature with RT in SG but correlation was non-significant in WG. RT was positively correlated with ST in SG (P < 0.05) and WG (P < 0.01). The pooled data analysis of both groups also indicated a positive correlation of maximum temperature with RT (P < 0.05). The morning respiration and pulse rate non-significantly varied in both group, however, in the evening, the respiration rate and pulse rate was more (P < 0.01) in SG in comparison to WG. No adverse effect of wallowing or shower treatment on mastitis incidence and general health of animals was observed.     

Morphological,Structural, and Thermal Properties of Starch Nanocrystals Affected by Different Botanic Origins

Six types of starch nanocrystals were prepared from corn, barley, potato, tapioca, chickpea, and mungbean starches with an acid hydrolysis method. The yields and morphological, structural, and thermal properties of starch nanocrystals were characterized. Starch nanocrystals had yields ranging from 8.8 to 35.7%, depending on botanical origin. During acid hydrolysis, amylose was effectively degraded, and no amylose was detected in any starch nanocrystal. Shape and size of native starch granules varied between starches, whereas there was no obvious difference in shape among different types of starch nanocrystals. The average particle size of starch nanocrystals was mainly related to crystalline type of native starches. Compared with their native starch counterparts, changes in crystalline diffraction patterns of starch nanocrystals depended on the original botanical source and crystalline structure. Degree of crystallinity, melting temperature, and enthalpy of starch nanocrystals increased, whereas their thermal decomposition temperature decreased. Of six produced starch nanocrystals, potato starch nanocrystal had the lowest yield, degree of crystallinity, and onset and melting temperatures, the largest particle size, and obvious changes in crystalline diffraction pattern.     

Assessment of genetic diversity in cabbage cultivars using RAPD and SSR markers

Genetic relationship and diversity among seven cabbage cultivars were analyzed using RAPD and SSR markers. These cultivars are of great commercial value in India and are confirmed for their reaction to black rot caused by Xanthomonas campestris pv. campestris. However, so far the extent of genetic diversity and relatedness has not been studied in these cultivars. A total of 17 selected RAPD primers generated 90 bands, 76 of which were polymorphic (84.44%). In addition, 27 selected SSR primers generated 67 amplified bands with 59 of which were polymorphic (87.6%). Though both the marker techniques were able to discriminate the cultivars effectively, analysis of combined data of markers (RAPD and SSR) resulted in better distinction of cultivars. By combining both the markers, a total of 157 bands were detected of which 135 bands (85.98%) were polymorphic, i.e. an average of 5.95 bands per primer. High level of polymorphism (> 85%) recorded with two different marker systems indicated a high level of genetic variation existing among the cultivars. Genetic relationship estimated using similarity co-efficient (Jaccard’s) values between different pairs of cultivars varied from 0.21 to 0.77 in RAPD, 0.42 to 0.82 in SSR, and 0.43 to 0.89 with combined markers. A high correspondence had been recorded between the values of genetic variations generated by UPGMA, clustering, and scatter plot diagrams. The cultivars ‘January King Sel. Improved’ and ‘Golden Acre’ are highly divergent cultivars as demonstrated by both the marker systems.