Epidemiology, induction of systemic resistance and management of charcoal rot of sesame incited by Macrophomina phaseolina (Tassi) Goid.
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Date
2020-01
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CCSHAU, Hisar
Abstract
Charcoal rot disease incited by Macrophomina phaseolina (Tassi) Goid. is the most destructive disease of sesame and causes heavy losses. The disease appears moderate to severe form every year in Haryana. Keeping in view of economic importance of this disease, the present study on epidemiology, induction of systemic resistance and management has been conducted under laboratory, screen house and field conditions during kharif 2017 and 2018 at CCS HAU, Hisar. Epidemiological studies showed the onset of charcoal rot varied in varieties HT 1 and HT 2 during different dates of sowing. The disease first appeared in early sown crop with higher disease incidence; however, disease appearance was delayed in mid and late sown with lower incidence of disease. The intensity of disease in mid sown and late sown was almost similar however; rate of disease progression was higher in late sown as compared to mid sown conditions. In vitro evaluation of non-conventional chemicals, salicylic acid (SA) was found most effective in inhibiting mycelial growth of M. phaseolina followed by IAA and IBA. Under screen house conditions, SA showed maximum reduction of charcoal rot incidence than other chemicals. Similarly, under field conditions, SA enhanced the yield and yield attributing traits than other treatments. Induction of total phenol content, total sugar content, peroxidase (POX), polyphenol oxidase (PPOX), phenylalanine ammonia lyase (PAL) and catalase activity was significantly increased by the treatment of SA followed by IAA, IBA and least by riboflavin. These activities reached at peak on six days after inoculation of pathogen and afterwards declined in both the varieties. However, variety HT 2 showed higher induction of biochemical activities than HT 1. Phytoextracts were evaluated for control of disease under in vitro conditions in which garlic extract (10%) showed maximum inhibition of mycelial growth followed by onion, karanj, neem and least by lantana extract. Similarly, under screen house conditions, garlic extract more reduced the incidence of charcoal rot than other phytoextracts. Under field conditions, seed treatment with combination of fungicides (carboxin+thiram) was most effective in controlling charcoal rot disease as well as enhanced the yield and yield attributing traits. Three hundred fifty sesame germplasm lines were evaluated for their relative resistance under field conditions in which majority of them showed moderately susceptible and susceptible reaction against charcoal rot. None of them identified as resistant, whereas only eighteen lines showed moderately resistant reaction against charcoal rotdisease