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Biocontrol of Seedling Blight by Co- Inoculation With Microbial Consortia

Thesis Info

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Author

Naseem Akhtar

Program

PhD

Institute

University of Agriculture

City

Faisalabad

Province

Punjab

Country

Pakistan

Thesis Completing Year

2016

Thesis Completion Status

Completed

Subject

Applied Sciences

Language

English

Link

http://prr.hec.gov.pk/jspui/bitstream/123456789/3081/1/Naseem_Akhtar_Soil_Science_2016_UAF_faisalabad..pdf

Added

2021-02-17 19:49:13

Modified

2024-03-24 20:25:49

ARI ID

1676725599219

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Compost has been used in agriculture since ancient time. It is useful to improve the fertility of the soil but its role in growth promotion and disease suppression is due to compost inhabiting bacteria (CIB). Plant growth promoting rhizobacteria (PGPR) regulate plant growth and act as biocontrol agents. Use of fungicide is common to control fungus, with detrimental residual effects. Biocontrol agents can be used to reduce the harmful effect of pesticides. Hypothesizing that PGPR and CIB can play role in controlling seedling blight in maize this prospect was studied with a consortium of PGPR and CIB. A number of PGPR and CIB strains were isolated from maize rhizosphere and compost respectively. After preliminary tests, twenty five isolates each of PGPR (Mb1 to Mb25) and CIB (Cb1 to Cb25) were selected and maintained for further experimentation. Fungal isolates were isolated from the maize plants, suffering from seedling blight. After in-vitro studies for germination test, twelve strains each of PGPR and CIB were selected, characterized and screened individually for growth promotion and disease suppression through jar experiments under axenic conditions. Synergism of isolates was also tested through in-vitro studies. The four best performing isolates of PGPR (Mb4, Mb5, Mb6 and Mb7) and CIB (Cb1, Cb4, Cb8 and Cb9) were selected to prepare consortium and test their compatibility through jar experiment under controlled conditions. Results showed that best performing consortium were Mb4 + Cb4, Mb4 + Cb9, Mb7 + Cb4 and Mb7 + Cb9. The potential of consortium for growth promotion and disease suppression was tested by trials in pots, under semi-controlled conditions. Disease severity decreased from 82% in the control to 11% in consortium inoculation. Intercellular CO2 concentration (Ci) was higher in the control (357 μmol mol-1 air) and decreased to 116 μmol mol-1 air in consortium inoculation. Higher values for stomatal conductance (165 mMm-2S-1), vapor pressure deficit (4 k-Pascal), evapotranspiration (5.7mM water m-2 S-1), assimilation of CO2 (19 μmol CO2 m-2s-1), water use efficiency (3.4%), chlorophyll a (2 mg g-1), chlorophyll b (3 mg g-1) and relative water contents (97%) were observed by single and consortium inoculation while membrane permeability (87.7%) was higher in control. Proline contents (5 μmol/g), total soluble sugars (11 mg g-1 FW), catalase activity (4.3 mM H2O2/min/g) and ascorbate peroxidase activity (0.63 μM H2O2/min/mg protein) were also significantly higher with inoculated treatment. Overall each set of the consortium suppressed disease and promoted the growth and yield of test crop. The bacterial metabolites of strains Mb4, Mb7, Cb4 and Cb9, as extracted by methanol were analyzed by HPLC system.The chromatograms of allisolates, exhibited different patterns and many peaks were detected. Based on comparison with standards, phenols in the metabolites were identified. Chlorogenic acid and caffeic acid were present in the metabolites of all four strains, while ferulic acid was present in smaller quantity in all isolates. Higher amount of ascorbic acid were detected in Mb7 and Cb9 while quercetin, gallic acid, p-caumaric acid, m- caumaric acid, vanillic acid and cinnamic acid were also present in all the isolates in smaller quantities. Root exudates were analyzed by HPLC against standards of pyruvic acid, citric acid, malleic acid, chlorogenic acid, oxalic acid, caffeic acid, fumaric acid, cinnamic acid and salicylic acid. Cinnamic acid and malleic acid were present in exudates of undiseased control while a diseased control contained chlorogenic acid, caffeic acid and salicylic acid. Exudates, collected from inoculated treatments containedchlorogenic acid, malleic acid and salicylic acid. Inoculation with PGPR isolates (Mb4, Mb7) induced the secretion of caffeic acid while that of Cb9 cause the induction of benzoic acid by roots under diseased conditions. The efficacy of different consortia was proved. Characterization of the selected bacterial isolates revealed that all isolates had more than one mechanism of action to control disease. Root exudates from soil ofundiseased plants could more effectively stimulate conidial germination than that from the diseased plants. Under undiseased condition root exudates had stimulatory effect on conidial germination (95% conidial growth) and showed highest germination, followed by control in diseased condition with 76% conidial growth. While lowest growth (39%) was observed by the addition of root exudates, collcted from consortium treatment in diseased soil. Compared with the root exudates from single inoculated plants, the root exudates from co-inoculated plants have significant effect to decrease the growth of conidia. The effect of the root exudates on mortality of spores ranges from 5 to 50% in undiseased soil and 24 to 61% in diseased soil. Root exudates, collected from single and consortium treatments from diseased soil showed decreasing trends of conidial growth compared to treatments with no exudates. Root exudates suppressed the growth of conidia by 43% (single inoculation) to 100% (by consortium) compared to treatments without exudates. The number of conidia varied from 3.2 to 3.5 × 105 CFU mL-1 by root exudates while the number ranges from 5 to 5.6 × 105 CFU mL-1 without exudates. Consortium showed 2.7 × 105 CFU mL-1 with exudates while treatment with no exudates showed 5.4 × 105 CFU mL-1. Root exudates supported the growth of bacteria in both, undiseased and diseased soil. All treatments with exudates enhanced the growth of bacteria compared to treatments with no exudates. Moreover growth with exudates from undiseased soil increased the growth more than from diseased soil. Consortium dominated supporting the growth of bacteria in both undiseased and diseased soil. Inoculation with the consortium of isolates exhibited percent increase in fresh cob (up to 53%) and dry cob (41%) yield, cob length (51%), grain yield (up to 55%), 1000-grain weight (up to 37%), K contents in grains and straw (1.8 and 0.8), %N in grain and straw (up to 2.7 and 1.0% respectively) and %P in grains and straw (up to 1.8 and 0.8% respectively) of maize compared to un-inoculated control. So the growth promotion caused by these selected consortia could be a function of multiple mechanisms. Co-inoculation overcome the adverse effects of pathogen and enhances the growth and yield of maize. Selected bacterial isolates could be used as biocontrol agent against Fusarium oxysporum in maize. However, the use of the bacterial isolates as biocontrol agents should be avoided without knowledge of the particular information about the compatibility of the isolates toward specific crop varieties, fungal isolates, soil and environmental conditions for which it could be used. In short, isolates of PGPR and CIB, recognized for the growth, yield promotion and diseases suppression could be used efficiently and effectively against specific host under specific set of soil and environmental conditions for maximum benefits.
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عشقے نے جد کڈھے وٹ

عشقے نے جد کڈھے وٹ
سارے ای گئے پچھے ہٹ
دوری سہی نہیں جاندی اے
عمراں گئی اے ساری کٹ
جس گھر رن کولہنی جی
کتے جاندے بھانڈے چٹ
ہٹ دھرمی وچہ سہوے پنجاہ
’’بھانویں پنج نہ سہندا جٹ‘‘
تھالی دے وچ کجھ وی نہیں
ویکھ بھڑولے خالی مٹ
یاراں نال حسابے کی
منہ توں پردہ پاسے سٹ
پڑھ درود نبیؐ سرور
ایسے گل تے جاویں ڈٹ

الأسس الفلسفية لأسلوب الحياة الإسلامية وغير الإسلامية وأثرها فى المجتمع: دراسة مقارنة

Philosophical Foundations of Islamic and Un-Islamic Pattern of Life and its Impact upon Society: A Comparative Study It is self-evident that human beliefs had great influence on character, actions, ethics, behavior and way of life. The possessors of correct belief produced positive effects and those who possessed incorrect belief promoted negative values in the community. Undoubtedly, the diversity in belief produced diverse ethics, actions, behaviour which gave birth to the different patterns of life in society. Regardless of subdivisions, by looking towards the philosophical foundations, these patterns of life could be divided into four categories in the light of the Qur’an and Sunnah. These lifestyles (also mentioned by Abū ’l-A‘lā Maudūdī in Tajdīd wa Iḥyā-i Dīn) are: Atheistic pattern of life, Polytheistic pattern of life, Monastic pattern of life and Islamic pattern of life. As each pattern had its particular tenets, therefore it formed a particular way of life by leaving its effects upon individual, social, political, economic, cultural and civilizational life. This research work aimed to explain the basic mechanism of these four patterns and their impact on human life. The method used for the collection and analysis of data was descriptive and analytical. The research concluded that three patterns of life (except Islamic pattern of life) produced harmful and negative effects into the society whereas the only Islamic pattern of life ensured the peace and prosperity. Moreover, Islamic pattern of life played a vital role in growth of all disciplines including political social, and economic system. It is therefore suggested that Islamic scholars should uncover the hollowness of Un-Islamic life style and present Islamic pattern of life in logical and systematic way. On one hand, this exercise will encounter the evils and on the other hand would promote good into the society.

Quality of Life and its Determinants in Subfertile Patients Seeking Fertility Care at Two Urban Fertility Centres in Nairobi

Introduction: Subfertility affects one in six couples worldwide with devastating psychosocial consequences impacting on quality of life (QoL). Assessment of QoL and institution of appropriate interventions in subfertility patients complements clinical management by reducing the psycho-social effects of subfertility and its treatment. No local or regional data exist on impact of subfertility on QoL using a fertility-specific QoL assessment tool. Objective: The study sought to determine the QoL of subfertile patients seeking fertility care at two urban fertility centres in Nairobi using the Fertility Quality of Life (FertiQoL) tool. Methods: This was a cross sectional study. Subfertile women of reproductive age (18-49 years) and their partners attending fertility clinics were recruited. Study participants completed the self-administered FertiQoL questionnaire, an internationally validated subfertility-specific tool consisting of 36 questions each on a five-point Likert scale. It assessed QoL in four core subscales (emotional, relational, social and mind/body) and two treatment subscales (tolerability and environment) with higher scores denoting better QoL. Mean FertiQoL scores and standard deviation (SD) were calculated for the total FertiQoL and subscales. Univariate analysis was used to examine association between age, sex, education status, comorbid conditions, duration of subfertility and cause of subfertility with QoL. Results: A total of 104 participants were recruited. The mean total FertiQoL score was 65.7 (SD=14.5). The mean Core FertiQoL score was 63.9 (SD=16.7). The emotional domain had the lowest mean score (57.5) while the relational domain had the highest mean score (72.5). Age less than 35 years was associated with lower emotional (P<0.04) and mind/body (P<0.03) scores. Previous live birth was associated with higher mind/body score (P<0.01). University education and previous pregnancy were associated with higher treatment environment (P<0.01) and treatment tolerability (P<0.005) scores respectively. Sex, cause of subfertility and type of treatment had no impact on QoL domain scores. No factor showed significant association with the total FertiQoL score. Conclusion: Study provided baseline QoL for the study population which is similar to that seen in other regions. Age more than 35 years, university education, previous live birth and previous v pregnancy had positive impact on FertiQoL subscales. There is need to assess QoL in subfertility patients using a reliable disease-specific tool such as FertiQoL.