ABSTRACT
The pathogen was identified based on its mycelial and sclerotial characters and pathogenicity test was proved by soil inoculation method. Efficacy of two non systemic fungicides (copper oxychloride and captan), two systemic fungicides (hexaconazole and tebuconazole) and one antifungal antibiotic validamycin each at different concentrations were tested against Rhizoctonia bataticola, incitant of dry root rot of chickpea under in vitro conditions. The fungicides copper oxychloride, captan, hexaconazole and tebuconazole were found to be highly effective (100%) in inhibiting the mycelial growth of the highly virulent pathogen at all the concentrations tested.
ABSTRACT
Mode of parasitism between Trichoderma and Rhizoctonia bataticola was examined under a microscope. Formation of several loops and coiling around the hyphae of pathogen, forming a thick compact rope like structure followed by rupturing, twisting and leakage of hyphal protoplasm, air bubbling inside the cytoplasm, breaking of cytoplasmic continuity, aggregation of cytoplasm within cell leading to severe vacoulation were observed at later phase of interaction.
ABSTRACT
The present investigation was under taken to study the extent of variability and genetic parameters with 16 parents and 48 hybrids for nine yield and its components and twenty five quality characters. The magnitude of difference between PCV and GCV was relatively low for all the traits, indicating less environmental influence. High GCV and PCV were recorded for harvest index, total number of productive tillers per plant and gelatinization temperature in parents and for total number of productive tillers per plant, number of grains per panicle, gelatinization temperature and amylose content in hybrids. High heritability coupled with high genetic advance as per cent of mean were recorded for gelatinization temperature, harvest index, total number of productive tillers per plant, number of grains per panicle, kernel length, kernel L/B ratio and grain yield per plant in case of parents and for gelatinization temperature, amylose content, total number of productive tillers per plant, number of grains per panicle and harvest index in case of hybrids indicating the additive gene effects in the genetic control of these traits and can be improved by simple selection in the present breeding material.
ABSTRACT
Crossandra is an important flower plant of our country earning a lot of revenue and trade. Of different diseases affecting crossandra cultivation, collar rot induced by Sclerotium rolfsii Sacc. is an important soil borne disease causing devastating losses. In the present study, the sensitivity of the collar rot pathogen was investigated. Also the compatibility of fungal biocontrol agent, Trichoderma spp. with these fungicides was worked out to for further devising Integrated Management strategies for collar rot disease. Four fungicides, viz., captan 50% WP, propiconazole 25% EC, thiophanate-methyl 70% WP and thiram 75% SD were evaluated at five different concentrations against collar rot pathogen, S. rolfsii. Further, the compatibility of these fungicides and the antagonist Trichoderma isolate-1 (T1). Results indicated that the fungicides, propiconazole, thiram and captan have significantly reduced the mycelial growth of test pathogen over control. Maximum inhibition was with propiconazole (100%), followed by thiram (81%) and captan (78%). Results on compatibility of Trichoderma spp. with these fungicides revealed that the bioagent was highly compatible with thiram (32% growth inhibition), followed by captan (47.5%). However, the Trichoderma isolate is not compatible with thiophanate methyl (88% growth inhibition) and propiconazole (100% growth inhibition). The Trichoderma isolate-1 (T1) and the fungicide, thiram were selected for further studies to devise integrated management strategies against collar rot disease.
ABSTRACT
Groundnut (Arachis hypogaea L.) is an annual legume which is also known as peanut, earthnut, monkeynut and goobers. It is the 13th most important food crop and 4th most important oilseed crop of the world. Groundnut seeds are a nutritional source of vitamin E, niacin, falacin, calcium, phosphorus, magnesium, zinc, iron, riboflavin, thiamine and potassium. Groundnut kernels are consumed directly as raw, roasted or boiled kernels or oil extracted from the kernel is used as culinary oil. It is also used as animal feed (oil pressings, seeds, green material and straw) and industrial raw material (oil cakes and fertilizer). These multiple uses of groundnut plant make it an excellent cash crop for domestic markets as well as for foreign trade in several developing and developed countries. The crop is affected by several diseases like leaf spots, collar rot, rust, bud necrosis, stem necrosis etc. Apart from these, aflatoxin is one of the major problems, produced in the infected peanut seeds by Aspergillus flavus Link ex fries and Aspergillus parasiticus Speare, particularly at the end of season under drought conditions (Diener et al., 1987). Aflatoxins are highly carcinogenic, immunosuppressive agents, highly toxic and fatal to humans and animals particularly affecting liver and digestive track. Aflatoxin is a potent human carcinogen. It is a naturally occurring toxic metabolite produced by certain fungi (Aspergillus flavus), a mold found on food products such as corn and peanuts, peanut butter. It acts as a potent liver carcinogen in rodents (and, presumably, humans). They are probably the best known and most intensively researched mycotoxins in the world. Aflatoxins have been associated with various diseases, such as aflatoxicosis, in livestock, domestic animals and humans throughout the world. In the present chapter, a detailed account on groundnut aflatoxins induced by A. flavus group of fungi was presented.