For effective varietal improvement of horticultural crops peach (Prunus persica) and nectarine (Prunus persica var. nucipersica), information about their population structure and genetic relatedness plays an important role. In this study we used retrotransposon-based markers (iPBS) to estimate the genetic diversity and population structure of 48 peach and nectarine genotypes from various distinct geographical regions of Punjab and Khyber Pakhtunkhwa, Pakistan. A total of 461 alleles were identified from PCR amplicons derived from nine iPBS primer pairs with an average of 8.5 alleles/locus. Among all four groups the genotypes collected from Swat and Hunza had the highest and the lowest expected heterozygosity, unbiased expected heterozygosity and Shannon’s information index, respectively. We constructed a Neighbour-Joining dendrogram and performed principal coordinate analysis based on the distance matrices, and both forms of analysis grouped the 48 genotypes into two distinct clusters. The STRUCTURE software distributed the forty-eight genotypes into two main populations (k?=?2) indicating a low diversity between genotypes collected from Chakwal, Swat, Mansehra and Hunza.
Fungal toxins in feed are leading issue in poultry industry causing a detrimental effect on the performance and health of poultry. The study was carried out to determine the incidence and concentration of the aflatoxins and their major producer Aspergillus flavus in home mix layer poultry feed in respect of seasonal variation throughout the year. A total of (n?= 204) home mix poultry layer feed samples were analyzed for the isolation of fungi. The isolates were initially screened through colony morphology and microscopic examination. However, aflatoxin concentration was determined by ELISA. Revealed results indicated that, the highest percentage of A. flavus was found during the months of June to August 50/54 (92.5%) followed by September to November 43/65 (66.1%), March to May 21/40 (52.5%), and December to February 18/45 (40%). As a whole, the incidence was recorded 132/204 (64.7%). Moreover, of the 132 samples, 41 (31%) were exceeded in respect of aflatoxin contamination from the legal limit (20 μg/kg) imposed by Food Drug Association (FDA). Statistically, the growth of A. flavus and aflatoxin production was found significantly different in respect of seasonal variation. As highest total viable fungal count (9.9?×?104 CFU/g) and aflatoxin level (72.27 μg/kg) were recorded during the months of June to August and lowest in December to February. Consequently, instantaneous essential control measures are demanded regarding appropriate storage and adequate drying in post-harvesting season. Along with surveillance plans and austere regulations for monitoring the aflatoxin contents for the wellbeing of consumers.
Heat stress at reproductive stages of cotton crop is the main cause for instability in yield than other abiotic stresses of crops. An experiment was conducted to observe the impacts of heat stress at squaring and flowering stages of cotton and potential of exogenously applied ascorbic acid to alleviate this stress. The experiment was planted for two consecutive years, that is 2013 and 2014, in randomized complete block design with split plot arrangement having three replications. Treatments were comprised of heat stress in main plots, viz. H0 = no heat imposition; H1 = heat imposition at square initiation; H2 = heat imposition at flower initiation and foliar‐applied ascorbic acid in subplots, viz. A0 = control or water spray; A1 = 20 mg/L; A2 = 40 mg/L; and A3 = 60 mg/L. Results showed that heat stress badly affected plant water relations (relative water contents and osmotic potential), total chlorophyll contents and activities of antioxidant enzymes that led to a corresponding decrease in seed cotton yield. Foliar application of ascorbic acid (40–60 mg/L) ameliorated adverse effects of heat and thus helped the crop to improve its water relations, stay green and antioxidant enzymes resulting into better crop yield. 相似文献
Limited water availability hampers the sustainability of crop production. Exogenous application of glycinebetaine (GB) and salicylic acid (SA) has been found very effective in reducing the adverse effects of water scarcity. This study was conducted to examine the possible role of exogenous GB and SA application in improving the growth and water relations of hybrid sunflower ( Helianthus annuus L.) under different irrigation regimes. There were three levels of irrigation, viz. control (normal irrigations), water stress at budding stage (irrigation missing at budding stage) and water stress at flowering stage (FS) (irrigation missing at FS). GB and SA were applied exogenously at 100 and 0.724 m m respectively, each at the budding and FS. Control plants did not receive application of GB and SA. Water stress reduced the leaf area index (LAI), leaf area duration (LAD), crop growth rate (CGR), leaf relative water contents, water potential, osmotic potential, turgor pressure, achene yield and water use efficiency. Nevertheless, exogenous GB and SA application appreciably improved these attributes under water stress. However, exogenous GB application at the FS was more effective than other treatments. Net assimilation rate was not affected by water stress as well as application of GB and SA. The protein contents were considerably increased by water stress at different growth stages, but were reduced by exogenous GB and SA application. The effects of water stress and foliar application of GB were more pronounced when applied at FS than at the budding stage. Moreover, exogenous GB application was only advantageous under stress conditions. 相似文献
The population dynamics of Bemisia tabaci and its parasitoids was studied on Gossypium hirsutum, Cucumis melo, Helianthus annus, Glycine max, Solanum melangena, Cucurbita pepo melopopo, Bauhinia pupurea, Morus alba, Albizzia lebbek, Lantana camara, Achyranthus aspera, and Convolvulus arvensis in cotton growing areas of Punjab, Pakistan during 2004 and 2005. Whitefly infested leaves having maximum number of second
to third instar were collected and kept in glass petri dishes with lid on at 28 ± 2°C and 65 ± 3% RH. Mean population of whitefly
adults that emerged per 200 cm2 leaf area per sampling period recorded was maximum on G. hirsutum (43.2), followed by C. melo (31.5), L. camara (23.0), H. annus (20.5), G. max (19.3), C. pepo melopopo (18.1), S. melangena (16.9), A. aspera (11.2), C. arvensis (9.2), B. pupurea (5.4), M. alba (5.3) and A. lebbek (5.0). Percentage parasitism was higher on G. hirsutum (44.3%), followed by C. melo (38.9%), A. aspera (38.3%), L. camara (38.1%), A. lebbek (35.3%), G. max (33.5%), C. arvensis (33.0%), M. alba (31.1%), B. pupurea (27.0%), S. melangena (24.8%), C. pepo melopopo (16.1%) and H. annus (15.2%). Overall the population of whitefly remained low during winter (November–February) and high during summer (May–August)
whereas, the percentage parasitism was higher during June–September and lower during December–February. The study revealed
that the availability of parasitoids could be enhanced by planting L. camara, B. pupurea, A. lebbek and M. alba in the cotton growing area. 相似文献
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