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Abstract Bio‐efficacy of 15 insecticides was evaluated against the pest complex of okra in the semi‐arid region of Rajasthan during July‐October, 1984. Five sprays given at intervals of 15 days throughout the crop period indicated that fenvalerate (0.02%) was most effective, followed by permethrin (0.02%), cypermethrin (0.02%), carbaryl (0.10%), monocrotophos (0.04%) and dimethoate (0.03%), against leafhoppers, aphids and fruit borer. The maximm yield of marketable fruits was obtained with fenvalerate, followed by cypermethrin, carbaryl, monocrotophos and dimethoate treatments. Highest net‐profit of Rs. 4890.00 was also recorded with fenvalerate treatment, followed by Rs. 4430.00 with carbaryl, Rs. 4148.00 with permethrin, Rs. 3977.00 with monocrotophos and Rs. 3053.00 with dimethoate treatments. A higher benfit cost ratio was found with carbaryl (1:9.78), followed by dimethoate (1:7.85), monocrotophos (1:5.18), methyl demeton (1:5.07), fenvalerate (1:3.43) and permethrin (1:2.41). These insecticides can also be used against insect pests of other vegetable crops of the season. 相似文献
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Summary A field experiment in concrete-based plots was conducted to estimate the contribution of N derived from air (Ndfa) or biological N2 fixation in Sesbania rostrata and S. cannabina (syn. S. aculeata), using various references, by the 15N dilution method. The two Sesbania species as N2-fixing reference plants and four aquatic weed species as non-N2-fixing references were grown for 65 days after sowing in two consecutive crops, in the dry and the wet seasons, under flooded conditions. Soil previously labeled with 15N at 0.26 atom % 15N excess in mineralizable N was further labeled by ammonium sulfate with 3 and 6 atom % 15N excess. The results showed that 15N enrichment of soil NH
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-N dropped exponentially in the first crop to half the original level in 50 days while in the second crop, it declined gradually to half the level in 130 days. The decline in 15N enrichment, in both N2-fixing and non-fixing species, was also steeper in the first crop than in the second crop. Variations in 15N enrichment among non-fixing species were smaller in the second crop. The ratio of the uptake of soil N to that of fertilizer N in N2-fixing and non-fixing species was estimated by the technique of varying the 15N level. In the second crop, this ratio in non-fixing species was higher than that in N2-fixing species. Comparable estimates of % Ndfa were obtained by using 15N enrichment of various non-fixing species. There was also good agreement between the estimates obtained by using 15N enrichment of non-fixing species and those by using soil NH
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-N, particularly in the second crop. By 25 days after sowing, the first crop of both Sesbania spp. had obtained 50% of total N from the atmosphere and the second crop had obtained 75%. The contribution from air increased with the age of the plant and ranged from 70% to 95% in 45–55 days. S. rostrata fixed substantially higher amounts of N2 due to its higher biomass production compared with S. cannabina. Mathematical considerations in applying the 15N dilution method are discussed with reference to these results. 相似文献
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Summary Antibiotic-resistant Rhizobium spp. strains have been used in ecological studies of legumerhizobia symbiosis. It has been suggested that in the course of acquiring resistance against high doses of antibiotics, rhizobia might lose their symbiotic effectiveness. Evidence both for and against this argument has been presented (Kremer and Peterson 1982; Materon and Hagedron 1983). This communication reports our experience with streptomycin-resistant (Str+) mutants of chickpea Rhizobium spp. strains. Parent strains were used as controls.Research paper No. 5233 from the Experiment Station, G.B.P.U.A.&T. Pantnagar, Nainital 相似文献
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Khirod K Sahoo Amit K Tripathi Ashwani Pareek Sudhir K Sopory Sneh L Singla-Pareek 《Plant methods》2011,7(1):1-11
Background
Common bean (Phaseolus vulgaris L.) is a crop of economic and nutritious importance in many parts of the world. The lack of genomic resources have impeded the advancement of common bean genomics and thereby crop improvement. Although concerted efforts from the "Phaseomics" consortium have resulted in the development of several genomic resources, functional studies have continued to lag due to the recalcitrance of this crop for genetic transformation.Results
Here we describe the use of a bean pod mottle virus (BPMV)-based vector for silencing of endogenous genes in common bean as well as for protein expression. This BPMV-based vector was originally developed for use in soybean. It has been successfully employed for both protein expression and gene silencing in this species. We tested this vector for applications in common bean by targeting common bean genes encoding nodulin 22 and stearoyl-acyl carrier protein desaturase for silencing. Our results indicate that the BPMV vector can indeed be employed for reverse genetics studies of diverse biological processes in common bean. We also used the BPMV-based vector for expressing the green fluorescent protein (GFP) in common bean and demonstrate stable GFP expression in all common bean tissues where BPMV was detected.Conclusions
The availability of this vector is an important advance for the common bean research community not only because it provides a rapid means for functional studies in common bean, but also because it does so without generating genetically modified plants. Here we describe the detailed methodology and provide essential guidelines for the use of this vector for both gene silencing and protein expression in common bean. The entire VIGS procedure can be completed in 4-5 weeks. 相似文献16.
Soil-solid phase associations of Se in seleniferous soils of Punjab were investigated by following sequential extraction procedures involving multiple extractions with 0.2 M K2SO4 (2 times), 0.1 M Na2SeO3 (4 times), 0.05 M NH4OH (4 times), 6 M HCl (2 times) and 9 M HNO3 (2 times) vis-a-vis single extractions with 0.25 M KCl, 0.1 M KH2PO4, 4 M HCl and concentrated HCl. Soil samples were equilibrated with 75Se (as Na2SSeO3) @ 9.25 kBq g - 1 soil by incubating at field capacity moisture regime and subjecting to alternate wetting and drying cycles. Following multiple extraction procedure, out of total 75Se added, 8.8 - 26.1% was present in readily available form (0.2 M K2SO4 extractable); 27.6 - 49.0% as isotopically exchangeable (0.1M Na2SeO3 extractable) and 5.3 - 12.0% as organic Se (0.05 M NH4OH extractable). Selenium extractable in K2SO4 was significantly correlated with free iron (r = - 0.774, p < 0.05) and CaCO3 (r = 0.670, p <0.10) content of the soils. Negative relationship was observed between Se uptake by maize (Zea mays L.) and ammonium hydroxide extractable (r = - 0.752, p <0.05) as well as residual Se (r = - 0.726, p <0.05) in soils. Highly positive coefficients of correlation between isotopically exchangeable Se and Se content (r = 0.851, p <0.01) as well as its uptake by maize (r = 0.841, p <0.01) indicated that the isotopically exchangeable form of Se may be considered as an index of bioavailable Se in seleniferous soils of Punjab. None of the fractions defined by following single extraction procedure was correlated with either the soil characteristics or Se uptake by maize plants. Multiple extraction procedure could, thus, better explain the distribution of Se in different fractions and uptake by plants. 相似文献
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Manoj K. Bhatt Kiran P. Raverkar Ramesh Chandra Navneet Pareek Rini Labanya Vineet Kumar Shikhar Kaushik Dhananjay K. Singh 《Soil Use and Management》2020,36(2):261-273
The imbalanced use of chemical fertilizers under intensive cultivation practices over a period of years leads to various soil-associated problems particularly nutrient availability. Thus, to examine the effect of long-term application of balanced and imbalanced inorganic fertilizer and farm yard manure (FYM) application on the chemical fraction of DTPA-extractable micronutrients under rice–wheat cropping system after 29 years, the observations were recorded from the ongoing field experiment at Govind Ballabh Pant University of Agriculture and Technology, Pantnagar, India. An application of balanced inorganic fertilizer with FYM in rice, while without FYM in wheat significantly improved the DTPA-extractable Zn, Fe, Mn and Cu after rice and wheat crops in both the surface and sub-surface soil layers. Lowest DTPA-extractable Zn, Fe, Mn and Cu were recorded, in surface and sub-surface soil under rice and wheat crops in control. The highest DTPA-extractable Zn, in both surface and sub-surface layers of rice (3.31, 1.62 mg kg−1, respectively) and wheat (2.96, 0.99 mg kg−1, respectively) was recorded because of application of N180+P80+K40+Zn(F) + FYM in rice and N180+P80+K40+Zn(F) in wheat. However, the DTPA-extractable Fe, Mn and Cu were highest in rice and wheat because of N120+P40+K40+FYM and N120+P40+K40 application, respectively. The balanced use of inorganic fertilizer with FYM (N180+P80+K40+Zn(F) + FYM) in rice and without FYM [N180+P80+K40+Zn(F)] in wheat supported the highest rice (6.74 t ha−1) and wheat (3.50 t ha−1) grain yields, while lowest in control. Based on the study results, long-term application of FYM at 5 tonnes ha−1 in rice crop sustained the availability of DTPA-extractable cationic micronutrients to rice and wheat in Mollisols. 相似文献
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Roy Subha M. P Jayraj Machavaram Rajendra Pareek C. M. Mal B. C. 《Aquaculture International》2021,29(3):1181-1217
The growing intensive aquaculture system around the world maintains a high stocking density, wherein it is essential to increase and sustain the optimum dissolved oxygen concentration (DO) through the provision of artificial aeration systems. The selection of an aerator is a crucial aspect of aquaculture operations. The selected aerator must be economically efficient and should be able to fulfill the requirement of oxygen supply in the pond water. The present study provides an extensive literature review on the importance of artificial aeration in aquaculture, the standard method of test for performance evaluation of an aerator, various aeration systems and their mechanisms, method to determine the numbers of aerator requirement, comparative studies of different type of aerators, and economic consideration in selection of aerators. In addition, a thorough analysis has been done to suggest the type of aerator that is economically viable and efficient for different pond volumes based on the performance data reported in the reviews. Therefore, this study may help the end-users (fish farmers) to select the best aerator based on their requirements.
相似文献20.