Category Archives: Volume 10 Nos. 3 & 4 (1988)

Note: Differential Sensitivity of Three Species of Drosophila to Two Cyclic Hydrocarbons


Author(s): V.A. Vijayan and N.B. Krishnamurthy

Abstract

Sensitivity of three Drosophila species namely D. melanogaster, D. nasuta nasuta and D. sulfuricaster neonasuta to two cyclic hydrocarbons, namely: Dithranol (1, 8, 9-trihydoxy anthracene), and 2,4-dichloro-1-naphthol was studied. Dithranol at 500, 750 and 1000 ppm and 2,4-dichloro-1-naphthol at 100, 150 and 200 ppm were administered to the larvae of the three species. Larval viability and development of all the species tested were significantly affected. Differential sensitivity of the three species in the light of their biomass is discussed.

Keywords : Drosophila melanogaster. D. nasuta nasuta. D. sulfurigaster neonasuta. Dithranol (1,8,9-trihydroxy anthracene). 2,4-dichloro-1-naphthol. Monomorphic strains. Mortality. Differential sensitivity. Toxicity.

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Effect of Varying Levels of Rock Phosphate on the Growth and Yield of Stylo (Stylosanthes guyanensis Aubl.) Under Acidic Soils


Author(s): Antontio I. Padaoil Jr. and Reynaldo R. Javier

Abstract

Height of stylo plants at first and second cuttings significantly increased upon application of 300 kg/ha rock phosphate (103.71 kg P2O5). Fresh herbage yield also increased when 100 to 400 kg/ha of rock phosphate was applied. Total fresh herbage and dry matter yields of Stylo applied with 100 kg/ha rock phosphate and supplemented with 30 kg N/ha and 60 kg K/ha were comparable to the yield of plants applied with 60 kg P2O5/ha from solophos. Plant tissue analysis from second to fourth cuttings revealed a general increase in P content, but not in N and K increasing rates of rock phosphate application.

Keywords : Stylosanthes guyanesis Aubl. Apatie. Rock phosphate. Acidic soild. Pasture legume.

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Effects of Method and Duration of Storing Seedpieces on Shoot Emergence and Growth of Abaca


Author(s): Arsenio D. Ramos and Nestor M. Gloria

Abstract

Percentage weight loss of abaca seedpieces placed in jute sacks and stored in a well-aerated nipa hut was higher than those covered with fresh banana leaves and stored in shaded field. These methods did not significantly affect percentage emergence, number of functional leaves per plant of 4-month old abaca. Duration of storage prior to planting significantly affected all the aforementioned parameters. Storing seedpieces for not more than 3 weeks by either method still favored vigorous growth of abaca plants. No significant interaction effects existed between methods and duration of storing abaca seepieces on shoot emergence and growth.

Keywords : Abaca. Seedpieces. Method of storage. Duration of storage. Shoot emergence. Growth

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Stress Cracking in Maize (Zea mays) Seeds


Author(s): Alfredo B. Escasinas and Murray J. Hill

Abstract

Maize hybrid D54 seeds were used to determine the effect of processing on stress cracking and the relationship between stress cracking in artificially dried seeds and loss of seed viability after storage. Considerable stress cracking occurred during the seed drying stage of processing. Some cracks significantly reduced seed germination after storage for 12 months. Cracks in the endosperm alongside or extending into the middle portion of the embryo as shown by x-ray analysis significantly decreased seed germination after storage. However, stress cracking did not reduce germination of seeds prior to storage. Visual cracks not detected by x-ray radiography and cracks outside the embryo did significantly decrease seed germination even after storage.

Keywords : Maize. Zea mays L. Seed cracking. X-ray radiography. Seed processing. Viability

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Effect of Different Factors on Germination and Tube Growth of Solanun sisymbrifolium Lam. Pollen


Author(s): K.M. Kuruvilla, Y.S. Chauhan, G. Das and J.S. Kharbteng

Abstract

Both germination and tube growth of Solanum sisymbrifolium Lam. Pollen require an optimum temperature of 25°C and a growth medium containing 100 ppm boric acid, 10% sucrose and 0.6% Bacto-agar. Pollen germination was stimulated by 5 and 10 ppm GA3, 1-10 ppm kinetin, 1 ppm ethylene, and 1 and 5 ppm ABA. Higher concentrations of these growth hormones reduced pollen germinability. Pollen tube elongation was stimulated by 10 ppm GA3, 1-10 ppm kinetin, 1 ppm ethylene and 1-10 ppm ABA. IAA at 5 to 25 ppm inhibited both pollen germination and tube growth. The degree of inhibition increased with higher concentrations of IAA.

Keywords : Pollen physiology. Solanum sisymbrifolium. Alkaloid. Germination. Tube growth. Growth regulators.

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Germination and Seedling Performance of Some Selected Coconut Hybrid Crosses


Author: Loida Z. Nasayao

Abstract

Dwarf coconut populations, namely: Orange Dwarf (OD), Coconino (CCN), Lingkuranay (LKY) and Tacunan (TAC) were pollinated by controlled hand pollination technique with Baybay Tall (BAY) as the common male parent to study the hybrid vigor of the resulting hybrids. Compared with their corresponding female parents, seedlings of OD x BAY, CCN x BAY and LKY x BAY exhibited hybrid vigor in terms of germination rate, girth size, height, and time from shoot emergence to leaf splitting. In, addition, leaf production rate was faster in OD x BAY and in CCN x BAY than their corresponding female parents. For TAC x BAY seedlings, the expression of hybrid vigor was evident only in height and girth size.

Keywords : Hybrid vigor. Controlled hand pollination technique. Coconut hybrids. Germination and seedling performance.

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Sporad Formation and Pollen Fertility of Nine Local Coconut Cultivars


Author: Tessie C. Nuñez

Abstract

Sporad formation and pollen fertility were studied in nine local cococut cultivars. Varying frequencies of abnormal sporads such as dyads, triads, pentads, hexads and heptads were observed. Normal sporads (tetrads) occurred highest in Lingkuranay (99%) and lowest in Coconino (58%). Pollen fertility ranged from 66% (Coconino) to 96% (Baybay Tall). Significant positive correlation (r=0.75) was seen between tetrad frequency and pollen fertility percentage.

Keywords : Coconut. Sporad formation. Pollen fertility.

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Assessment of Inoculation Techniques and Evaluation of Fungicides Against Potato Fusarium Dry Rot


Author(s): Lucia M. Borines and Marina P. Natural

Abstract

Five methods of inoculating Fusarium spp., the causal organisms of potato dry rot, were assessed to find the most suitable technique to evaluate the effectiveness of fungicides against the disease. Depositing 0.2 mL of spore suspension (105 spores/mL) of Fusarium spp. Into holes in the tubers was the best inoculation method resulting in 75% tuber infection at 12 days after inoculation. Seven fungicides were evaluated for their effectiveness in controlling the disease in stored potato tubers. Benlate at the rate of 3 tbsp/ 19 L water was most effective in minimizing tuber infection and lowering the rate of lesion development. Dithane M-45 and Captan were also effective in controlling the disease and are good alternative for Benlate.

Keywords : Fusarium dry rot. Potato. Inoculation techniques. Evaluation. Fungicides.

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Microorganisms with Improved Saccharogenic and Proteolytic Properties for Root Crop-Based Soy Sauce


Author:Julie C. Diamante

Abstract

Mold isolates coded as RT, JJ and LL and identified as Aspergillus flavus Link. var. columnaris var. nov., A. niger van Tieghem and A. phoenicis (Cda.) Thom., respectively; when used in soy sauce production; yielded high amounts of sugar and protein. The appearance, aroma, color. Flavor and general acceptability of root crop-based soy sauce produced by A. flavus var. columnaris were comparable to those produced by A. sojae and A. oryzae. However, only the aroma of the soy sauce produced by A. phoenicis using sweet potato flour was comparable to the control and that produced by A. flavus var. columnaris. When cassava flour was used; appearance, aroma and color were comparable to the control soy sauce and that produced by A. flavus var. columnaris. A. niger produced the least acceptable soy sauce in terms of all sensory qualities considered when sweet potato flour was used. With cassava flour, the aroma and flavor of the product were comparable to the control and that produced by A. flavus var. columnaris. Aflatoxin was not detected in any soy sauce produced by the test microorganisms.

Keywords : Root crop-based soy sauce. Aspergillus spp. Saccharogenic and proteolytic activities. Chemical composition. Sensory qualities.

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Size Composition, Distribution, Length-Weight Relationship and Natural Food of the Blue Crab, Portunus pelagicus (L.) in Selected Coastal Waters in Leyte and Vicinity, Philippines


Author(s): Corazon B. Batoy, Bernardita C. Pilapil and Josephine F. Sarmago

Abstract

Female blue crabs were relatively smaller than males. More smaller crabs (carapace lengths <50 mm) were observed in January, April and July in consonance with reported intense spawning periods. Most crabs (males and females) were generally between 60 to 70 mm long. Spatial distribution was size-related with the larger crabs (carapace lengths >50 mm) usually caught at depths greater than 6 meters and juvenile ones (carapace lengths <30 mm) found in shallower portions or near the shore. This distribution apparently resulted from migration patterns which are probably responses to the necessities of breeding, molting and feeding and is affected by salinity and substratum. Females were slightly heavier than males.
The natural diet composition of P. pelagicus in descending order of percentage occurrence in its guts includes Osteichthyes, Holothuroidea, Algae, Echinoidea, Sea grass, Gastropoda, Copepoda, Amphipoda and Bryozoa. Food items particularly animals with hard parts were ingested in large recognizable pieces; few small food items were ingested in their entirely; others were ingested such that their soft tissues were almost completely separately from hard parts. Plant food was also ingested in fragments.

Keywords : Portunus pelagicus (L.). Size composition. Distribution. Length-weight relationship.

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