Browsing by Author "DEVENDRA, R."
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ThesisItem Open Access CUTICLE HERBICIDE INTERACTION ON PENETRATION AND ROLE OF SURFACTANT ON ENHANCED HERBICIDE POTENCY(UNIVERSITY OF AGRICULTURAL SCIENCES GKVK BANGALORE, 2000-11-11) UMAMAHESH, V.; DEVENDRA, R.ThesisItem Open Access "INFLUENCE OF SEASQN AND MICROCLIMATIC VARIATION EFFECT ON HERBICIDE EFFICACY"(UNIVERSITY OF AGRICULTURAL SCIENCES GKVK BANGALORE, 2002-08-30) CHANDRANAIK, M.; DEVENDRA, R.ThesisItem Open Access OXYGEN (A18O) AND CARBON (A13C) ISOTOPE COMPOSITION IN PLANTS - AN APPROACH TO QUANTIFY TRANSPIRATION AND MESOPHYLL FACTORS ASSOCIATED WITH WATER USE EFFICIENCY(UNIVERSITY OF AGRICULTURAL SCIENCES GKVK BANGALORE, 2001-05-03) BINDU MADHAVA, H.; DEVENDRA, R.ThesisItem Open Access ROLE OF SENESCENCE AND ADJUVANTS IN HERBICIDE ON ITS EFFICACY AND SPROUTING ABILITY OF Cyperus rotundus L.(University of Agricultural Sciences, Bangalore, 2010-07-16) DHANRAJ; DEVENDRA, R.Cyperus rotundus is one of the most noxious weed which propagates through underground plant parts (tubers).Controlling this weed by herbicide more effective than hand weeding. Glyphosate is an eco-friendly with no residue in soil, less mammalian toxicity, high water solubility, highly translocative and non-selective herbicide widely used in wide spaced horticultural crops by directing the spray. It was observed that in resistant weed species lack of translocation from fed leaf to meristematic apex is one of the mechanism to cause resistance. Studies showed that senescence induced by glyphosate increases the 14C-glyphosate and 14C-2,4-D translocation and its efficacy. Several experiments were conducted to standardize the duration and dosage of glyphosate to induce senescence. Senescence followed by herbicide application substantially reduced sprouting ability of tubers as reflected by reduced number of shoots produced per tuber both in non-dormant and dormant tubers of Cyperus rotundus. The ideal duration found to induce senescence is 48hr and 8ml/lit of glyphosate concentration followed by 8ml/lit of glyphosate is the best dosage to control Cyperus rotundus. Leaf chlorophyll content, membrane integrity and relative water content were affected by glyphosate, ethephon and paraquat and repair mechanism of membrane and higher RWC after 48hr of glyphosate to induce senescence proved to be more effective than other senescence agents. Glyphosate along with adjuvant (jaggery 1%) application showed, to enhance the herbicide efficacy and reduce tuber viability of Cyperus rotundus drastically. The tubers exposed to higher temperature (750C) either by hot water irrigation to pots or dipping in hot water or exposing tubers to hot air oven for 30minute were lost their viability (TTC test- 2, 3, 5- Triphenyl Tetrazolium Chloride). Different formulation of glyphosate, Roundup (8ml/lit) isopropyl amine salt (41%EC) and Meera 71(10gm/lit) ammonium salt of glyphosate (71% SG) had same efficacy. However Sure shot (0.03%) with Meera 71 enhanced the efficacy 1.33 fold of Meera 71 in control of Cyperus rotundus.ThesisItem Open Access Suppression of Parthenium hysterophorus L. using allelochemicals: Development of Technique to use plant residues as a source of allelochemicals(University of Agricultural Sciences GKVK, Bangalore, 2008-08-08) ARUN KUMAR, N.; DEVENDRA, R.Parthenium hysterophorus is a thermo insensitive, C3-C4 intermediate, low photorespiration and day neutral plant belonging to the family Asteraceae. It is drought tolerant, no seed dormancy and produces 30000 seeds /plant. Parthenium is native of Allelopathic weed plants extracts of Lantana camara, Hyptis suaveolens and Cassia uniflora were used as mulch and pelleted extracts to control parthenium. Mulching of by Lantana followed by Hyptis significantly reduced germination of parthenium compared to Cassia. The percent reduction in germination compared to respective control were 70, 24.6, 45 % for Lantana and 35, 34, 12% respectively for Hyptis mulching in Parthenium, sunflower and tomato. Mulching decomposed plant material upto 30 days suppressed growth and development of parthenium at 2.4t/ha plant material. However, fresh botanical agents were more effective than decayed material. In order to enhance the efficacy of allelochemicals, the extracts were stored in different coloured bottles and exposed to sunlight for 21 days. None of the sunlight exposed extracts enhanced allelochemicals efficacy as reflected by germination and growth of parthenium. Microbial degradation of allelochemicals in soils was assessed. Sterilized soil suppressed germination significantly compared to non-sterilized soil. Further presence of botanical agents extracts completely inhibited germination of parthenium in sterilized soil than non-sterilized soil confirming role of microbes. Due to non-availability of the plant material through out the year, plant extracted solution was pelleted. Jaggery fermented extracts showed more inhibition than nonfermented pellets reflected by reduced growth and development of parthenium. Pellets from 157 increased to 471/m2, significant reduction of root and shoot growth of parthenium was observed. Release of allelochemicals from pellet was assessed at different pH; release was more in 7.85pH buffers for Hyptis pellet and for Cassia and Lantana release of allelochemicals was substantially high in 5.0 pH buffer. Mexico, Cuba and West Indies.