Bioefficacy and residual effect of the new generation herbicide pyrazosulfuron ethyl in transplanted rice (Record no. 27550)
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| 000 -LEADER | |
|---|---|
| fixed length control field | 07220nam a2200181Ia 4500 |
| 003 - CONTROL NUMBER IDENTIFIER | |
| control field | OSt |
| 005 - DATE AND TIME OF LATEST TRANSACTION | |
| control field | 20220927101708.0 |
| 008 - FIXED-LENGTH DATA ELEMENTS--GENERAL INFORMATION | |
| fixed length control field | 140128s9999 xx 000 0 und d |
| 082 ## - DEWEY DECIMAL CLASSIFICATION NUMBER | |
| Classification number | 630 |
| Item number | POO/BI PHD |
| 100 ## - MAIN ENTRY--PERSONAL NAME | |
| Personal name | Poornima Yadav P I |
| 245 ## - TITLE STATEMENT | |
| Title | Bioefficacy and residual effect of the new generation herbicide pyrazosulfuron ethyl in transplanted rice |
| 260 ## - PUBLICATION, DISTRIBUTION, ETC. (IMPRINT) | |
| Place of publication, distribution, etc. | Vellayani |
| Name of publisher, distributor, etc. | Department of Agronomy, College of Agriculture |
| Date of publication, distribution, etc. | 2006 |
| 502 ## - DISSERTATION NOTE | |
| Degree type | PhD |
| 520 3# - SUMMARY, ETC. | |
| Summary, etc. | An investigation entitled “Bioefficacy and residual effect of the new generation herbicide pyrazosulfuron ethyl in transplanted rice” was undertaken to study the bioefficacy of pyrazosulfuron ethyl for evolving a suitable and economic weed management strategy for transplanted rice, to find out the residues of pyrazosulfuron ethyl in soil, rice grain and straw and to screen the most suitable indicator plant to detect the PSE residues in soil. The study consisted of four parts and the first part was a field investigation undertaken at the Instructional Farm, College of Agriculture, Vellayani, during the period from August 2004 to March 2005 for two consecutive seasons, ie., the second and third crop seasons. The experiment was laid out in RBD with eight treatments and three replications. The treatments included PSE at four doses viz., 15 (T1), 20 (T2), 25 (T3) and 30 (T4) g ai ha-1, butachlor @ 1.5 kg ai ha-1 (T5), weed free check (T6), unweeded check (T7) and hand weeding at 20 and 40 DAT (T8), i.e., farmers’ practice. Perusal of the results showed a significant increase in the plant height, tiller number, leaf area index and dry matter production during both the seasons due to weed management practices especially PSE at higher doses. All weed management practices significantly improved yield attributes. Among these, PSE at 20, 25 and 30 g ai ha-1 (T2, T3 and T4 respectively) were the most effective treatments. Weed free check and unweeded check registered the highest and lowest values for all these characters respectively. During both the seasons, the weed free check recorded the highest grain yield and was comparable with treatments involving PSE at higher doses. Pooled analysis of the yield data over the two seasons also revealed a similar trend and no seasonal interaction was noticed. The yield loss due to weeds was maximum in unweeded check during both the seasons as evident from the highest weed index recorded in these plots (46.11 and 38.13 per cent during the second and third crop seasons respectively). Results of the study also revealed that among the weeds, Isachne miliacea Roth ex Roem. et Schult., Echinochloa colona (L.) Link, Cyperus iria L., Cyperus difformis L., Fimbristylis miliacea (L.) Vahl., Monochoria vaginalis (Burm. F), Marsilea quadrifolia L. and Ludwigia parviflora Roxb. were the most predominant species in the experimental field. The herbicide PSE at higher doses viz., 20, 25 and 30 g ai ha-1 (T2, T3 and T4 respectively) significantly reduced grasses, sedges and broadleaved weeds population and dry matter production of weeds. The weed control efficiency (WCE) of these treatments was superior to butachlor (T5) and hand weeding twice (T8) too. Nutrient uptake by rice plants revealed that PSE involving treatments recorded higher N, P and K uptake next to weed free check. In general, all weed management treatments including PSE, butachlor and hand weeding twice registered lower values for nutrient uptake by weeds. However nutrient uptake by weeds was minimum under PSE treated plots, i.e. 30, 25 and 20 g ai ha-1. Economic analysis revealed that the new generation microherbicide PSE at higher concentrations viz., 20, 25 and 30 g ai ha-1 gave higher net income and benefit cost ratio during both the seasons. The highest net income and benefit cost ratio of Rs. 27388 and 1.86 and Rs. 22728 and 1.72 respectively were realized by PSE @ 20 g ai ha-1 during the first and second crop seasons respectively. Dynamics of soil microbial population consequent to the application of PSE revealed that the herbicide caused an inhibitory effect on the growth of fungi and bacteria at the initial stages, but 30 days after the herbicide application the microbes regained their original population indicating its safety to these organisms. The population of soil actinomycetes and earthworms was not affected by weed management practices. From the above results it can be concluded that application of PSE did not cause any long term lethal effect on soil microorganisms. Bioassay was conducted as the second part of the experiment wherein the most sensitive indicator plant for assessing PSE residue in soil was identified as the first step. Among the three different indicator plants tested, viz., cucumber, maize and sunflower, cucumber was identified as the most sensitive one and its shoot length was selected as the best parameter for assessing the residual effect of PSE in soil, based on standard curves and response equations developed. Bioassay studies carried out subsequently with cucumber, using the post experiment soil samples revealed no phytotoxic concentration of herbicide residue in it. The third part of the experiment was the estimation of residue of PSE in the post experiment soil and rice grain and straw adopting instrumentation technique. Results revealed a total absence of PSE in soil as well as in grain and straw, i.e., no detectable residue could be observed. This emphasizes the safety of the chemical to soil environment as well as the safety of the produce for human and animal consumption. An in vitro study to test the effect of PSE on soil borne rice pathogens viz., Pyricularia oryzae, Helminthosporium oryzae and Rhizoctonia solani was conducted as the fourth part of the experiment. Results revealed that PSE at different concentrations tested, significantly inhibited the radial growth of pathogens at initial stages of inoculation. Rate of mycelial growth decreased as the concentration of PSE increased in the medium. PSE @ 20 ppm enhanced the production of sclerotia which was on par with control. But PSE at higher concentrations tested, i.e., 50, 60 and 70 ppm decreased the number of sclerotia produced. This finding signifies the additional benefit of suppression of soil borne rice pathogens by the application of this microherbicide. The present study revealed the superiority of the LDHE herbicide PSE at 20, 25 and 30 g ai ha-1 applied at 10 DAT on weed control and yield of transplanted rice. However, based on economic analysis pyrazosulfuron ethyl @ 20 g ai ha-1 at 10 DAT can be recommended as an efficient and economic weed management practice for low land rice as it ensures the highest net income and BC ratio. The bioassays and residue analysis ensures the safety of the chemical to soil environment and also the safety of the produce for human and animal consumption. In addition to its potent use in weed management in the rice ecosystem, PSE has shown immense suppressive effect on some of the dreaded soil pathogens affecting the crop. |
| 700 ## - ADDED ENTRY--PERSONAL NAME | |
| Personal name | Elizabeth K Syriac(Guide) |
| 856 ## - ELECTRONIC LOCATION AND ACCESS | |
| Uniform Resource Identifier | http://krishikosh.egranth.ac.in/handle/1/5810015092 |
| 942 ## - ADDED ENTRY ELEMENTS (KOHA) | |
| Source of classification or shelving scheme | |
| Koha item type | Theses |
| Withdrawn status | Lost status | Source of classification or shelving scheme | Damaged status | Not for loan | Permanent Location | Current Location | Shelving location | Date acquired | Full call number | Barcode | Date last seen | Price effective from | Koha item type |
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| KAU Central Library, Thrissur | KAU Central Library, Thrissur | Theses | 2014-03-18 | 630 POO/BI PHD | 172609 | 2014-03-18 | 2014-03-18 | Theses |