Morphological Character Variations in Lasiodiplodia Species: Pathogen of Inflorescence Dieback in Cashew Growing Ecologies of Nigeria | Chapter 8 | Current Research Trends in Biological Science Vol. 1

Nine isolates of Lasiodiplodia theobromae were collected from cashew inflorescences showing typical symptoms of dieback disease in nine different farms belonging to various cashew growing ecologies of Nigeria. The result revealed that most of the Lasiodiplodia species isolates exhibited significant differences in morphology, colour and spore dimensions. The colony growth rate of Lasiodiplodia species range from 11.95 mm to 14.17 mm, colony texture and colour of the isolates in the obverse were fluffy dark mouse grey, fluffy mouse grey, fluffy olivaceous grey or fluffy groh grey while the reverse colour of the isolates was either greyish blue or sky grey. Sporulation was observed at varied degrees in all the Lasiodiplodia species isolates except in isolates from Oro and Ejule and likewise is the numbers of pycnidia produced varied in all the isolates across growing ecologies. Significant variations were observed in the characters and morphology of the Lasiodiplodia species isolates causing inflorescence dieback of cashew in Nigeria. Conidia of all isolates are septated with single septa but the septa sizes varies and conidia sizes also differ. Eigenvalues and variance proportion consistently decreased among selected characters and the proportional contribution of each character to the total variance also varied in dimension and quantity. Four clusters significantly evolved in the dendogram with 2, 2, 4 and 1 isolates within each cluster.

Author(s) Details

Dele Omoyele Adeniyi
Department of Plant Biology, University of Ilorin, P.M.B. 1515 Ilorin, Nigeria and Plant Pathology Section, Cocoa Research Institute of Nigeria, P.M.B. 5244, Ibadan, Nigeria.

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Thermophilic Bacteria: Novel Polymers for Biotechnological Applications | Chapter 01 | Advances and Trends in Biotechnology and Genetics Vol. 3

Aims: We analyzed thermotolerant bacterial isolates of thermophiles from various regions in South East coasts of India. They were analyzed for Fatty Acid Methyl Ester (FAME) for identification and classification.

Study Design: A total of forty three (9.6%) thermotolerant bacterial isolates of thermophiles were secluded out of 444 isolates obtained from water samples from the Adyar River, Marina coast, Muttu Kadu Backwaters, Kovalam coast (India) and a prawn hatchery. In addition, a novel thermotolerant Gram positive Bacillus type bacterium from the pelletized feed of fish was examined. A total of 18 thermotolerant bacteria were analyzed for Fatty Acid Methyl Ester (FAME).

Results: Amongst 134 isolates that grew on E. coli FAGI agar, 23 (17%) were thermotolerant when tested at 15 psi for 30 min. Of the 72 isolates that grew on Staphylococcus Baird Parker agar 10 (13%) were thermotolerant, whilst among the 128 isolates that grew on Salmonella agar ÖNÖZ 10 (8%) were thermotolerant. In contrast, none of the 110 isolates that grew on TCBS agar (Vibrio sp.) exhibited thermotolerance, although they were isolated from the same regions as the other bacteria. The optimal temperature for the growth of most thermophiles was 45°C, except for 9 isolates. Of the latter, 7 grew at 50°C, one at 52°C and one at 55ºC, respectively.There were some extremely thermotolerant bacterial isolates that exhibited consistency in profuse growth at 15 psi (121°C) for 30 min. Other isolates showed inconsistency in growth after autoclaving the cultures at 15 psi (121°C) for 30 min, and these bacteria showed development of endospores. Isolates of thermotolerant bacteria that grew on Staphylococcus Baird Parker agar and Salmonella agar ÖNÖZ were predominantly antibiotic resistant when compared with those bacterial isolates that grew on E. coli FAGI agar. A major 43 kDa toxin-protein as well as 15 other minor protein subunits was detected in the thermotolerant Bacillus sp. isolate. The proteins were toxic and caused mortality to goldfish Cyprin macrophthalmus. The thermotolerant bacteria were identified as B. cereus, Bacillus subtilis, B. pumilus, B. laevolacticus), B. alcalophilus, Kurthiasibirica, Geobacillus stearothermophilus, Staphylococcus schleiferi and S. gallinarum,

Conclusions: This study documents 43 thermotolerant bacterial isolates from water samples and a Bacillus-type bacterium from fish feed in Chennai region, India and these bacterial isolates offer the potential for exploitation in biotechnological applications.

Author(s) Details

Palaniappan Ramasamy
Research and Development Wing, Sree Balaji Medical College and Hospital, BIHER (Bharath University), Chromepet, Tamil Nadu, Chennai-600044, India.

Aruna Sharmili
Department of Biotechnology, Stella Mary’s College, Tamil Nadu, Chennai-600032, India.

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Optimizing Nitrogen Application in Onion (Allium cepa L.): Influence of Rate and Time of Topdressing on Growth, Yield and Quality | Chapter 10 | New Perspectives in International Plant and Soil Research Vol. 1

Onion (Allium cepa L.) is an important commercial vegetable crop grown by small-holder farmers in Kenya for both local and export markets. The national average production is low and quality is highly compromised due to use of low yielding varieties and poor agronomic practices. Field experiments on the influence of nitrogen and time of application on growth, yield, and quality of onion bulbs were conducted in 2014 and 2015 at the National Agricultural Research Laboratories. The experiments were laid out in a Randomized Complete Block Design (RCBD) with a split-split arrangement and replicated three times. Nitrogen (N) was applied as Calcium Ammonium Nitrate at five levels including, 0 (control), 26, 52, 78 and 104 kg N ha-1. These were applied at four different times of applications at three, six, nine and twelve weeks after transplanting. Two onion varieties popularly grown in Kenya were used, the Red Creole and Red Tropicana F1 hybrid. Nitrogen and time of application showed significant differences in all parameters studied except bolting. Nitrogen at 104 kg N ha-1 applied at 6 weeks gave the best results with regard to plant height, number of leaves, bulb ratios, bulb diameter, average bulb weight, yield and marketable yield. Six weeks after transplanting was the best application time with regard to most parameters and maturity of the crop. Yields increased linearly with increased N rates but declined by over 23% with late application at 12 weeks. High rates resulted to thick necks and increased split bulbs especially with late application at 9 and 12 weeks. Red Tropicana F1 hybrid was the best performing variety with regard to most parameters especially total and marketable yield. Nitrogen applied at the right time improves growth, increases yield and improves quality. Since the yield response was linear in both seasons, higher rates should be evaluated to get the optimal rate. Time of application equally affected growth, crop maturation and yield as well as yield components with late application negatively affecting these parameters. From this observation it is apparent that sufficient N is required early in the season. When it is deficient in the juvenile stage, rapid growth is restricted, resulting to loss of yield and poor quality bulbs. Thus it is essential that an optimum level of N is supplied early for maximum yield and improved bulb quality. The predicted optimum time of N application from this study was six weeks after transplanting. Nitrogen at 104 kg/ha applied at 6 weeks after transplanting gave the best growth, yield and quality of bulbs. Application of too much N late in the season (9 and 12 weeks) increased split bulbs and neck sizes. Excessive application late in the season (as farmers do) should be discouraged and avoided in the regime for best results. This shows that an optimal rate applied at the right time (4R’s of nutrient management) optimizes the efficiency of fertilizer use for good yields and hence profitability. Although hybrid seed was expensive, the yield obtained was high and quality was fairly good. The Red Tropicana F1 hybrid obtained maximum yield of 30,533 kg/ha at 104 kg N/ha applied at 3 weeks while the Red Creole obtained a maximum yield of 24,674 kg/ha with the same level applied at the same time. To improve production and marketability, Kenyan farmers should adopt the hybrids.

Author(s) Details

M. W. Gateri
National Agricultural Research Laboratories, Institute of Crops Research, Kenya Agricultural and Livestock Research Organization, P.O.Box 14733-00800, Nairobi, Kenya.

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The Population Dynamics of the Mudskipper, Periophthalmus barbarus (LINNEAUS 1766) (TELEOSTEI, GOBIIDAE) and the Implication for Conservation and Management in the Mangrove Swamp of Iko River Estuary, Southeastern Nigeria | Chapter 05 | Recent Advances in Biological Research Vol. 3

The population dynamics of Periophthalmus barbarus in the mangrove swamp of Iko River estuary, southeast of Nigeria were obtained from a twenty four month length composition data ranging 4.6 – 14.5 cm total length (TL) (mean 9.1841± 1.6346: n = 2,876) corresponding to 1.16 – 50.6 g total weight (TW) (mean = 9.9626 ± 5.4796) the growth was exponential. The asymptotic length (L∞) of the Powell-Wetheral plot (L∞ = 15.03 cm) was seeded into FSAT II (FAO-ICLARM Stock Assessment Tools II) software to obtain best estimates of von Bertalanfy growth parameters as L∞ = 16.22 cm TL, growth coefficient (K) = 1.2 year-1, age of fish at zero length, to = 0.071, longevity, tmax = 2.5 years. The estimated growth performance index, φ’ = 2.449. Other FISAT II growth parameters were the amplitude of growth oscillation, C = 0.6 and the winter point, WP = 0.6, Rn = 0.3127. Mortality parameters were total mortality, Z = 479 year-1, natural mortality, M = 2.39 year-1 and fishing mortality, F was 2.40 year-1. Result indicate the fishery is optimally exploited with current exploitation rate, Ecur = 0.50 < Emax = 0.668 > Eopt = 0.5 which suggests stock optimal exploitation, corroborated by Z/K ration (3.184).  Ecur (0.5) means that 50% of the available stock is being fished annually. The length-at-first capture Lc = 7.33 cm TL and Lc/L∞ was 0.45, indicating the fish was yet to complete 55% of growth as at the time of capture at Lc, hence P. barbarus in the ecosystem is at the optimal level of exploitation as well as the presence of growth overexploitation. Thus to circumvent the consequences of growth overfishing, sustainable fisheries measures such as monitoring of fishing effort, use of selective gears and increase in mesh size should be encouraged, implemented and enforced. The study has revealed that P. barbarus population residing in the mangrove swamp of Iko River Estuary is experiencing exploitation rate close to the maximum sustainable yield amidst the presence of heavy fishing pressure. Moreover, the mudskipper fishery in this ecosystem is currently exhibiting growth overexploitation signs which could lead to severe implications on the population size and food security within vulnerable fishing households in the future. Therefore, urgent management interventions in the form of monitoring fishing efforts, return of captured juveniles back to the water body from the non-selective fishing gear and use of selective gear with large mesh size (to increase length at first capture) are needed to safeguard this important fish species from possible collapse in the future.

Author  Details:

Dr. Nsikak Abiaobo

Department of Zoology, Akwa Ibom State University, Ikot Akpaden, Mkpat Enin, P.M.B. 1167, Akwa Ibom State, Nigeria.

Dr. Mfom Tmothy Udo

Department of Fisheries and Aquatic Environment Management, University of Uyo, P.M.B. 1017, Akwa Ibom State, Nigeria.

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