1. KAUTIR (Kerala Agricultural University Theses Information and Retrieval)
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Item Etiology and characterization of diseases of Anthurium (Anthurium andraeanum L.) in Kerala(Department of Plant Pathology, College of Agriculture, Vellanikkara, 2021) Nitha Rafi; Anita Cherian, KAnthurium (Anthurium andraeanum L.), a native of Tropical America is a perennial herbaceous plant commercially grown for its attractive coloured spathe and green shiny foliage. These have great economic value in the global flower trade that led to the budding of many urban and rural anthurium entrepreneurs in the countryside, particularly in the state of Kerala. During the recent past, the cultivation of this high valued cut flower crop is challenged by many biotic factors and the changes in climate scenario occurred recently led to the emergence of various new pests and diseases. Hence the present study was undertaken to identify and document the diseases affecting anthurium grown in the state of Kerala and the characterization of associated pathogens. Purposive sampling surveys were conducted in the anthurium cultivated locations of six districts viz. Thrissur, Ernakulam, Palakkad, Malappuram, Kozhikode and Wayanad during the period from October, 2020 to July, 2021. The incidence and severity of various symptoms were assessed and collected the samples for further studies. Twelve leaf spots (KMALS, PBALS, VFNLS, VCNLS1, VCNLS2, IJKLS, KKYLS, OKMLS, OLRLS, TLRLS, TBMLS and NLBLS) two leaf blights (VFNLB and OLKLB), one root rot (VCNRR), one wilt (MNTLW) four inflorescence rots (MNTSR, CKDSR, PNMSR and ALVSR) and one mosaic symptom (VCNML) were collected during the survey. Among the leaf spots, PBALS recorded the highest per cent disease severity (PDS) of 58.23 followed by NLBLS (46.66 %) and ALVSR recorded the highest severity of 32 per cent among inflorescence rots. Isolation and pathogenicity studies of the associated pathogens yielded 18 fungal and two bacterial isolates. Symptomatology of these diseases were studied both under natural and artificial conditions. The fungal pathogens were characterized and identified by studying cultural and morphological characteristics. Based on these characters, leaf spot pathogens were identified as Colletotrichum gloeosporioides, Lasiodiplodia theobromae, Phoma sp., Phomopsis sp., Corynespora sp., Pestalotiopsis sp. and those causing inflorescence rot as Colletotrichum gloeosporioides and Phomopsis sp. and root rot pathogen as Phytopythium sp. and wilt pathogen as Fusarium sp. The bacterial isolates causing leaf blight were identified as Xanthomonas sp. based on cultural, morphological and biochemical characteristics. The viral like symptoms subjected to electron microscopy revealed the absence of any virus particles. PCR amplification of Internal Transcribed Spacer (ITS) region of the fungal genome followed by sequencing and in silico analysis confirmed that the pathogen associated with TBMLS as C. queenslandicum, VCNRR as Phytopythium vexans, IJKLS as Diaporthe phaseolarum, KKYLS and OKMLS as Phomopsis heveicola, NLBLS as Lasiodiplodia theobromae, TLRLS as Pseudopestalotiopsis thea, VCNLS2 and OLRLS as Corynespora cassiicola, MNTLW as Fusarium fujikuroi. The pathogens associated with KMALS, PBALS, VFNLS, MNTSR, PNMSR and ALVSR belong to Colletotrichum gloeosporioides species complex. The bacterial isolates (VFNLB and OLKLB) were confirmed as Xanthomonas axonopodis through the amplification of 16S rRNA region of the genome followed by sequencing and in silico analysis. An in vitro experiment was conducted to study the efficacy of fungicides and biocontrol agents/bioformulations against major fungal pathogens. Fungicides viz. propineb, difenoconazole, carbendazim 12 % + mancozeb 64 %, cymoxanil 8% + mancozeb 64 % and Bordeaux mixture were highly effective against L. theobromae and Colletotrichum sp. (PBALS) as it resulted in cent per cent inhibition of these two pathogens at all the three doses. In the case of P. vexans, fungicides viz. propineb, azoxystrobin, carbendazim 12 % + mancozeb 64 %, cymoxanil 8% + mancozeb 64 % and Bordeaux mixture were found to be effective even at a lower dose. Among the three chemicals tested against Xanthomonas axonopodis, maximum inhibition was recorded in the case of streptocycline. Dual culture and filter paper disc method revealed that the biocontrol agents/formulations viz. Trichoderma sp., PGPR-II and PGPM were effective against all the tested fungal and bacterial pathogens. Pseudomonas fluorescens was found effective against three fungal and the bacterial pathogen.Item Cost- effective methods and devices for home scale adoption of plant tissue culture(Department of Horticulture, College of Agriculture, 1996) Deepa, V; Reghunath, B RAttempts were made to develop cost-effective methods and devices for home scale adoption of plant tissue culture in the plant tissue culture laboratory of the Department of Horticulture, College of Agriculture, Vellayani, during 1993-95. The test plant selected for the study was Anthurium andreanum Lind. (Pink). Segments of leaf were used as explant for cullus initiation. The callus so obtained was used for further regeneration studies. Various low cost equipment were fabricated and tested for their efficiency in comparison to the conventional expensive method. One-fourth strength of the major nutrients of MS medium along with full strength of micro nutrients was found good for the induction of multiple shoots. All the growth parameters were found adversely affected by the use of LR grade chemicals, when compared to AR grade chemicals. Confectionary grade sugar was found to be equally good to AR grade sucrose, while commercial grade crystal sugar was not. Rain water could be used as a substitute to double glass distilled water in the culture medium. Attempts to substitute agar-agar with less expensive playing marbles, as support matrix of the culture medium was also successful. Ordinary (gold-smith type) balance could be used to replace the expensive electronic balance in weighing chemicals for media preparation. The pH indicator paper could be effectively used instead of the pH meter, in adjusting pH of the medium. Ordinary colourless glass bottles and jam jars could be economically used, instead of expensive borosilicate glassware. The domestic pressure cooker was equally efficient as the electric autoclave in sterilising culture medium and containers. The expensive refrigerator could be effectively replaced with ice-packed thermocol boxes. Instead of the laminar airflow cabinet, the fabricated transfer hood could be effectively used. Attempts to substitute artificial flourescent light with natural light were successful. Rooted plantlets when planted out exhibited 30 per cent loss during various stages of hardening. The cost of producing a single anthurium plantlet was Rs. 5.16 in the conventional method, whereas in the cost-effective method it could be brought down to Rs. 1.82.Item Standardisation of growing media and organic nutrition for juvenile anthurium plants (Anthurium andreanum Lind.)(Department of Pomology and Floriculture, College of Agriculture, Vellayani, 2005) Shajma Nafeesa Basheer; Sabina George, TAnthuriums are herbaceous perennials belonging to the largest genus of the family Araceae. Anthurium andreanum Lind. called the ‘Painter’s palette’ flower is the most important species grown in the tropics. Anthurium cultivation on a commercial basis is gaining popularity in Kerala because of its high demand in the foreign market. The lack of proper management practices has increased the total period taken for the production of marketable flowers to nearly 2-2½ years. The present work was thus taken up with a view to standardize growing media and organic nutrient dosage for young anthurium plants, for enhancing their early vegetative growth and for earlier production of flowers having desirable floral attributes of size and quality. The experiment was carried out at the Department of Pomology and Floriculture, College of Agriculture, Vellayani during 2003–2005 with a view to standardize the growing media and organic nutrient dosage for young anthurium plants. The anthurium cultivar chosen for this study was Anthurium andreanum ‘Tropical’, a commercially important cultivar of Kerala. The treatments consisted of thirty six combinations of four media treatments namely sand + leaf compost (M1), sand + coir pith compost (M2), granite + leaf compost (M3) and granite + coir pith compost (M4) and nine nutrient treatments including weekly application of three cowdung treatments (2, 4 and 6 g l-1 extract) and bimonthly application of three organic manure mix (25, 50 and 75 g) treatments. Growing media, nutrient treatments and their interactions influenced vegetative growth, flower characters, vase life, fresh weight and dry matter production and nutrient content of leaves. Among the media, sand + coir pith compost was found to be the best for obtaining greater plant height, leaf area, leaf duration, petiole length at third and fourth week after emergence, shortest phyllachron, the highest fresh and dry weight of leaves and their N and K content. Plants grown in this medium also recorded earlier flowering, greater number of flowers per plant, increased spathe size, greater length and thickness of flower stalk and enhanced vase life. The inclination of spadix and its length and thickness were also found to be greater tending towards those of mature plants in this medium. Vegetative growth enhancement was also obtained with 4 g l-1 and 6 g l-1 fresh cowdung extract treatments at varying stages of growth. Greater fresh weight and dry weight of leaves were recorded in plants receiving 4 g l-1 cowdung extract at 165 and 225 DAT. These plants also recorded greater N and K content during the period while the P content was greater in plants receiving 6 g l-1 at these periods. Increased spathe size, lesser number of days to flowering, maximum length of flower stalk, maximum vase life and lesser number of days to harvestable maturity of flowers was obtained with 4 g l-1 extract. Application of organic manure mix were also found to give beneficial effects. Plants receiving 25 g organic manure mix recorded greater plant heights and leaf area during the latter stages of growth. This dosage also resulted in greater leaf duration and greater petiole length during the first and second week after leaf emergence. Fresh and dry weight of the leaves recorded were greater in plants receiving 75 g mix. The shortest phyllachron was recorded with 50 g dosage and the longest was recorded with 75 g / plant. The N and K content of the leaves were greater in plants receiving 25 g mix while the P content was greater in plants receiving 50 g mix. Spathe size, length of the flower stalk as well as the vase life of flowers was greater in plants receiving 25 g OM mix. The interaction between media treatment, cowdung and organic manure treatments were also found to influence the performance of plants.