Decay of Yam (Dioscorea Alata L.) in Odisha, India ABSTRACT

253 Journal of Pharmaceutical, Chemical and Biological Sciences ISSN: 2348-7658 CODEN: JPCBBG Impact Factor (GIF): 0.701 Impact Factor (SJIF): 3.905 September- November 2017; 5(3):253-258 Published on: November 04, 2017 The work is licensed under Research Article Plants used as Biofungicides against Storage- Decay of Yam (Dioscorea alata L.) in Odisha, India Akhtari Khatoon1, Ashirbad Mohapatra2, Kunja Bihari Satapathy1* 1P.G. Department of Botany, Utkal University, Vani Vihar, Bhubaneswar-751004, Odisha, India 2Sri Jayadev College of Education and Technology, Naharkanta, Bhubaneswar-752101, Odisha, India *Corresponding Author: Kunja Bihari Satapathy, P.G. Department of Botany, Utkal University, Vani Vihar, Bhubaneswar-751004, Odisha, India Received: 15 June 2017 Revised: 25 September 2017 Accepted: 05 October 2017 ABSTRACT Petroleum ether and alcoholic leaf extracts of Abutilon indicum (L.) Sweet, Ageratum conyzoides L., Alstonia scholaris (L.) R.Br., Artocarpus heterophyllus Lam., Averrhoa carambola L., Cassia fistula L., Centella asiatica Urban. and Dillenia indica L. were tested for their antifungal activity against fungi responsible for storage decay of Dioscorea alata L. tubers namely Aspergillus niger, Geotrichum candidum and Fusarium oxysporum under aseptic laboratory condition. These fungi were isolated from the rotten yam tubers collected from different market places of Odisha, India. The fungitoxic potential of plant extracts was compared with four synthetic fungicides such as Blitox-50, Dhanustin, Indofil M- 45 and Mancozeb. The results of the present study revealed that the plant extracts also had significant inhibitory effect against the three test fungi when compared to four synthetic fungicides. The results on the efficacy of eight plant extracts against three fungi indicated that against Aspergillus niger and Geotrichum candidum, the petroleum ether extract of Ageratum conyzoides was most effective in inhibiting its growth while against Fusarium oxysporum, petroleum ether extract of Averrhoa carambola was found most promising. Keyword: Post-harvest decay; yam tubers; plant leaf extracts; antifungal activity; bio-fungicides INTRODUCTION transported to store houses and consumed Vegetables are vital source for human nutrition throughout the year. Yam (Dioscorea alata) is a as well as a cheaper source of vitamins and cultivated tuber crop and it is unique for its food, minerals. They are responsible for maintenance medicinal and economic values [1]. About 100 g of good health and also beneficial in protecting of yam tuber yields 118 calories of energy. It is against some degenerative diseases. Different also an important source of complex parts of vegetables are used for human carbohydrates and soluble dietary fibre. It is consumption which may belong to different reported to be a source of dietary fibre that help botanical groups with varying cultural and reduce constipation and decrease bad cholesterol environmental requirements. The vegetables (LDL) levels besides other medicinal uses such grouped under root and tuber category are most as reducing colon-cancer risk as well as important as compared to other vegetables being regulating blood sugar level. The crop is drought non-perishable in nature. After harvest they are tolerant and provides a wide harvesting window J Pharm Chem Biol Sci, September-November 2017; 5(3):253-258 Khatoon et al 254 which makes it available throughout the year. Collection and identification of plant However, post-harvest storage decay of the material tubers due to infestation of microorganisms is The leaves of eight medicinal plants such as the important factor for the loss in its production Abutilon indicum (L.) Sweet, Ageratum and contributes largely to the unsuccessful conyzoides L., Alstonia scholaris (L.) R.Br., storage practice of these root tubers [2-4]. In Artocarpus heterophyllus Lam., Averrhoa Odisha, the post-harvest rotting of these tubers carambola L., Cassia fistula L., Centella asiatica during storage poses serious problem sustaining Urban. and Dillenia indica L. were collected heavy losses particularly for the warm and from the “Chandaka reserve forest” area near humid climate in the state. To control Bhubaneswar, Odisha in March, 2015 (Fig 1). phytopathogenic microorganisms of crop plants, The test plants were identified by following the chemical pesticides have been used to control the “Flora of Orissa” [8]. The voucher plant plant diseases in agriculture. A number of specimens were deposited in the herbarium of problems are also seen against the effective use Post Graduate Department of Botany, Utkal of these chemicals in the agricultural areas University, Vani Vihar, Bhubaneswar. The where the fungal pathogens have developed leaves were collected in bulk amount, washed in resistance [5]. Besides overuse of the chemicals tap water, dried under shade and made to coarse and fertilizers increased the risk of high-level powder form to be utilized for their antifungal toxic residues in the products which are study. hazardous for human consumption as well as the ecosystem. Thus, the problem has drawn the Processing of plant material and interest on the research of possible use of plant preparation of extract extracts for control of pest and diseases in The leaves collected were shade dried and agriculture which was less harmful to the ground to form coarse powder and successively human health and environment [6, 7]. extracted with the solvent petroleum ether and methanol by Soxhlet apparatus [9] and the MATERIALS AND METHODOLOGY extract was recovered under reduced pressure in Collection of rotten samples, Isolation and a rotatory evaporator. The extracts were kept in Identification of associated Fungi desiccators for further use. Yam tubers showing the symptoms of rotting were randomly collected from different market In vitro evaluation of antifungal efficacy of places and store houses of Odisha and brought to plant extracts the Laboratory of Microbiology, Post Graduate For the evaluation of the efficacy of the Department of Botany, Utkal University, fungitoxicity, the petroleum ether and Bhubaneswar, Odisha (India) for further methanolic leaf extracts were diluted with 50 % phytopathological analysis. The diseased dimethyl sulfoxide (DMSO) @ 20mg/ml. Then samples were washed with tap water and antifungal efficacy of the plant extracts was sterilized the surface with 0.1% mercuric carried out following the method of Satish et al. chloride solution for 2-3 minutes. Small piece of (2007) with some modification [10]. For sample rotten tissue from the rotten sample was taken treatment, 1 ml of diluted plant extract was with a sterile knife and placed on potato mixed with 19 ml of Potato Dextrose Agar (PDA) dextrose agar (PDA) medium and incubated at and the mixture was poured into each petri room temperature for 24 hours. Representative plate, mixed thoroughly and allowed to solidify, colony types were purified by sub-culturing on making the concentration of plant extract on fresh PDA plates. Pure cultures were PDA medium 1mg/ml. PDA medium without the transferred to slants of PDA and the isolates plant extracts was used as control. Disc of 0.5 cm were grown singly on PDA for identification. The culture of the test fungi was placed at the centre isolates were identified with the help of the of the petri plate following poison food technique available literature. Authentication of (both sample and control) and incubated at 28 ± identification was made in the Department of 1 ºC for respective days (e.g. Aspergillus niger for Mycology and Plant Pathology, College of 8 days, Fusarium oxysporum for 10 days and Agriculture, Odisha University of Agriculture Geotrichum candidum for 11 days) of their and Technology (OUAT), Bhubaneswar, India. growth up to 8 cm diameter (complete growth). J Pharm Chem Biol Sci, September-November 2017; 5(3):253-258 Khatoon et al 255 The antifungal effect of each plant extract was formula as below: estimated by measuring the radial growth (cm) % Inhibition = (X-Y)/X x 100 of the fungal pathogen using ruler. The where X= average increase in mycelial growth in fungitoxicity of the plant extracts in terms of control, Y= average increase in mycelial growth percentage inhibition was calculated by using in treatment [10]. Fig 1: Photo of test plant materials Comparison of the efficacy of selected RESULTS AND DISCUSSION fungicides and plant extracts: Isolation of fungi from the rotten sample A separate experiment was conducted for From the present investigation it was found that comparison of the relative efficacy of four Aspergillus niger, Geotrichum candidum and synthetic fungicides namely Dhanustin, Fusarium oxysporum were associated with Mancozeb, Blitox-50, Indofil M-45 and 16 leaf storage-decay of yam tubers in market places extracts (petroleum ether and methanolic and store-houses of Odisha. extracts) of eight selected plants against the test fungi under study. The concentration of In vitro antifungal efficacy plant extracts fungicides was 0.05 mg/ml. Fungicides (0.5 and synthetic fungicides mg/ml) and plant extracts (1 mg/ml) were In-vitro fungitoxic efficacy of eight medicinal incorporated after sterilization in PDA medium. plants against three plant pathogenic fungi Five test fungal isolates were inoculated into the revealed that all the test plants were more or medium in three replicates and were incubated less effective in inhibiting the mycelial growth of for respective days of their growth as described the fungi causing storage rot of

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