Cytoplasmic differentiation using near-isonuclear polycytoplasmic male sterile lines in pearl millet

Summary Five near-isonuclear polycytoplasmic versions of 81A₁ and two of Pb 402A₃ male sterile lines of pearl millet (Pennisetum typhoides), along with their corresponding maintainer lines (81B and Pb 402B) were studied for 14 agronomic and two disease traits, and for isozymes of peroxidase in anthers and leaves for assessing cytoplasmic differences. Significant differences among isonuclear polycytoplasmic lines of both 81A₁ and Pb 402A₃, having the same genome and variable cytoplasms, were observed for several agronomic traits. Banding pattern of peroxidase isozymes revealed clear cut differences among cytoplasms. The results provide evidence for the influence of cytoplasmic factors on the phenotypic expression of nuclear genes.     

Number of crosses and population size for participatory and classical plant breeding

In the breeding of self-pollinating crops, crossing creates variation upon which selection is exerted. If the value of crosses cannot be predicted then this uncertainty means that many crosses need to be made. However, since there is a limit to the capacity of a breeding programme, more numerous crosses result in each cross having a small population size, fewer progenies in later generations and a lower probability of recovering good genotypes from each cross. Published theory on the optimum number of crosses in a plant breeding programme, for a predominantly self-pollinating crop, usually assumes that all crosses are equal value. This overestimates the number of crosses required. When the optimum size of a population in a favourable cross is considered, theory predicts that very large populations are desirable. The required population size is even larger if linkage of loci controlling different traits is also considered. Hence, in an inbreeding crop, one possible strategy is to select a small number of crosses that are considered favourable and produce large populations from them to increase the probability of recovering superior genotypes. In an out breeding crop, the analogy is a few composites with large population sizes. This low-cross-number strategy is ideally suited to the particular constraints and advantages of participatory plant breeding. Such an approach, although not essential, may still be advantageous in classical breeding. When a breeding programme is based on few crosses, which parents are chosen is crucial and farmer participatory methods are highly effective in narrowing the choice. Modified bulk population breeding methods, and recurrent selection are desirable strategies in the participatory plant breeding of self-pollinating crops when combined with a low-cross-number approach. This revised version was published online in August 2006 with corrections to the Cover Date.     

Implications for dosing regimen of enrofloxacin administered concurrently with dexamethasone in febrile buffalo calves

Tropical Animal Health and Production - The objective of the study was to determine the influence of dexamethasone (DXM) on pharmacokinetics (PK) and pharmacodynamics (PD) of enrofloxacin (ENR) for...     

Inheritance of resistance to Bacillus thuringiensis Cry1Ac toxin in Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) from India

BACKGROUND: The cotton bollworm, Helicoverpa armigera (Hübner), is one of the most serious insect pests of cotton. It has developed resistance to almost all groups of chemical insecticides because of their intensive use. The failure of insecticides to control H. armigera has been a strong incentive for the adoption of transgenic cotton (Bt cotton). However, the value of Bt could be diminished by widespread resistance development to Bt toxins in insect populations. Therefore, understanding the genetic basis of resistance is essential for developing and implementing strategies to delay and monitor resistance. RESULTS: A resistant strain designated as BM‐R was obtained from the cross of adults from Bathinda () and Muktsar (), Punjab, India, which showed the highest survival (60.68%) and LC₅₀ value (1.396 µg mL^?1 diet). Similarly, a laboratory‐maintained strain from Hoshiarpur, Punjab, showed maximum susceptibility to Cry1Ac toxin with the lowest LC₅₀ value (0.087 µg mL^?1), and was designated as HP‐S. The genetic purity of both strains was confirmed by RAPD profile analysis at each generation, and genetic similarity reached more than 90% after the third generation. Continuous maintenance of the resistant BM‐R strain on Cry1Ac resulted in an increase in LC₅₀ from 0.531 µg mL^?1 in F₀ to 4.28 µg mL^?1 in F₁₄ and 7.493 µg mL^?1 in F₁₉, while the LC₅₀ values for HP‐S larvae on diet without Cry1Ac increased to 0.106 and 0.104 µg mL^?1, which lay within the fiducial limits of the baseline LC₅₀ value. The mode of inheritance of resistance was elucidated through bioassay response of resistant, susceptible heterozygotes and backcross progeny to Cry1Ac incorporated in semi‐synthetic diet. CONCLUSION: Based on dominance, degree of dominance and backcross values, resistance was inferred to be polygenic, autosomal and inherited as a recessive trait. Copyright © 2011 Society of Chemical Industry     

Water-drop stability of PVA-treated natural soil aggregates from different land uses

Soil erodibility is a function of land use as it affects the stability of soil aggregates. The use of soil conditioners like polyvinyl alcohol (PVA) may help in reducing the soil erodibility, but it is important to economize the use of PVA. A study was carried out to evaluate the interactive effects of land use and PVA concentration on the water-drop stability of natural soil aggregates collected from eroded, forest, agricultural and grass lands. The water-drop stability of these aggregates was monitored using single raindrop simulator. The water-drop stability was lowest in eroded soils, followed by soils from agriculture, forest and grass lands. The smaller aggregates were more stable than the bigger ones. The water-drop stability of aggregates of different sizes and from different lands increased with the application of polyvinyl alcohol (PVA). The mean water-drop stability increased with the application of PVA at the rate of 0.05% by 40% in 2–5 and 5–10 mm aggregates. Increasing the PVA concentration to 0.1 and 0.2% increased water-drop stability value by 71–73% and 87–88%, respectively. The PVA application at the rate of 0.1% could increase the water-drop stability of soils under eroded land equivalent to that of the untreated grassland soils.     

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.     

Variation in melon (<Emphasis Type="Italic">Cucumis melo</Emphasis>) landraces adapted to the humid tropics of southern India

We present here the first comprehensive genetic characterization of melon landraces from the humid tropics of southern India. The genetic diversity among 50 melon landraces collected from 3 agro-ecological regions of southern India (6 agro-ecological sub-regions) was assessed by variation at 17 SSR loci, morphological traits of plant habit and fruit, 2 yield-associated traits, pest and disease resistance, biochemical composition (ascorbic acid, carotenoids, titrable acidity) and mineral content (P, K, Fe, Zn). Differences among accessions were observed in plant and fruit traits. Melon germplasm with high titrable acidity, higher than average amounts of mineral content and resistance to Cucumber mosaic virus, Zucchini yellow mosaic virus, powdery mildew (races 1, 2, 3, 5), Fusarium wilt (races 1, 2), Aphis gossypii and leafminer was recorded in the collection. A high level of genetic variability in melon germplasm was suggested by the SSR analysis. Comparative analysis using SSRs of the genetic variability between Indian melons from north, south, and east regions and reference accessions of melon from Spain, France, Japan, Korea, Iraq, Zambia showed regional differentiation between Indian melon accessions and that Indian germplasm was weakly related to the melon accessions from other parts of the world, suggesting that an important portion of the genetic variability found within this melon collection has not been used yet for the development of new cultivars. Additional collections of acidulus melon germplasm should be made in southern India and adequate management of this important genetic resource is clearly a necessity.     

Involvement of proline in response of chickpea (Cicer arietinum L.) to chilling stress at reproductive stage

Chickpea is sensitive to chilling stress, especially at its reproductive stage and experiences abortion of flowers and poor pod set at temperatures below 10 °C. The metabolic controls governing chilling-sensitivity in chickpea, particularly involving proline are not known. Hence, in the present study we explored the role of proline in this regard. A set of chickpea plants (cv. GPF2) growing under warm conditions of the glass house (temperature – 28/14 °C as average maximum and minimum till early flowering stage) was exposed to low temperature conditions of the field (8.3–9.6/2.8–5.3 °C; average maximum and minimum temperature, respectively) during the onset of reproductive phase while another set of plants continued to grow under warm conditions. In case of chilling-stressed plants, one set of the plants was treated with 10 μM proline while the other set not treated with proline served as control under low temperature conditions. In untreated chilling-stressed plants, the endogenous proline increased to 230 μmol g⁻¹ dry weight (DW) on 4th day of stress and decreased thereafter to reach 28 μmol on 7th day. In plants treated with 10 μM proline, its endogenous content reached 310 μmol g⁻¹ DW on 4th day and stayed significantly higher than untreated chilling-stressed plants. The proline-treated plants showed significant improvement in retention of flowers and pods leading to better seed yield compared to the untreated ones. The proline-applied plants also had greater pollen viability, pollen germination, pollen tube growth and ovule viability. The stress injury measured as oxidative stress, electrolyte leakage, loss of chlorophyll and decrease in leaf water content was mitigated significantly in proline-treated plants. Additionally, proline application increased the level of sucrose and trehalose (cryoprotectants) in chilling-stressed plants. The studies revealed that proline application was significantly effective in reducing the impact of chilling injury on reproductive growth in chickpea.     

A double-blinded placebo-controlled evaluation of adipose-derived mesenchymal stem cells in treatment of canine atopic dermatitis

Mesenchymal stem cells (MSCs) have emerged as a new therapy for various immune-mediated inflammatory diseases. In this study we perform the first double-blinded, placebo-controlled evaluation of the efficacy of adipose-derived allogenic canine MSCs for the treatment of canine atopic dermatitis (cAD). Enrolled canine patients were randomly divided into placebo (PBS saline), low-dose (5?×?10⁵ cells/kg), and high-dose (5?×?10⁶ cells/kg) treatment groups. Each patient received three subcutaneous MSCs treatments or PBS saline at four-week intervals with injections at five sites. Patients were monitored by physical exams, pruritus visual analog scales (PVAS) signed by the primary caretaker, canine atopic dermatitis extent and severity index-4 (CADESI-4) scores by two veterinarians, and complete blood count and serum chemistry analysis along with laboratory analysis for potential biomarkers. Patients were kept off any immune-modulating drugs during the study period, and oral antibiotics and topicals were used for managing pruritus and secondary infections. The PVAS scores and the serum miR-483 levels were significantly lower in the high dose group compared to the placebo group at day90 post first-treatment. The CADESI-4 scores of the high dose group also showed downward trends. No severe adverse effects were observed in any patient in this study. The high dose MSC treatment is efficacious in alleviating the clinical signs of cAD until 30 days after the last subcutaneous administration of MSCs, and miRNA-483 may be a reliable prognostic biomarker for cAD. The MSCs efficacy and potential biomarkers should be further explored by a larger scale clinical trial.