Monthly Archives: October 2018

Development of waterjet-assisted cassava peeler

Author(s): Raymond G. Sumaria1 and Daniel Leslie S. Tan2*


The study aimed to develop a water jet-assisted cassava peeler and evaluate its technical performance in terms of peeling capacity, peeling efficiency, and tuber loss during peeling. Performance evaluation of the developed peeler included treatments which were the combinations of the three methods of peeling (use of circular nozzle, use of flat nozzle, and the manual peeling using a knife) and three diameter ranges of cassava roots (35 ± 5mm; 45 ± 5mm;55 ± 5mm). Results showed that the peeling capacity of the water jet-assisted peeler with circular nozzle was significantly higher than manual peeling but not significantly different to the water jet-assisted peeler with flat nozzle. The diameter of cassava roots used also significantly affected the peeling capacity of the different peeling methods; lower capacity for smaller diameter cassava roots and higher capacity for bigger diameter cassava roots.

Keywords : cassava peeling, peeler, water jet

Annals of Tropical Research 40(2):124-134(2018)

Financing needs and financial management practices of banana (Musa balbisiana) farmers in Inopacan, Leyte

Author(s): Pauline S. Caintic1*, Analita A. Salabao2 and Marlon M. Tambis3


This study investigated the financing needs and the financial management practices of banana farmers in Inopacan, Leyte, the relationship between financial management practices to profitability and the relationship of the various socio-demographic variables to the relevant financial management practices. The relevant financial management practices considered in this study were those found to be significantly related to profitability. Results showed that limited capital for labor and the occurrence of pests and diseases particularly bugtok, which is caused by a bacterium called Ralstonia solanacearum, were among the major problems expressed by the banana farmers that need financing. Financial management practices such as monitoring the status of loan and financial planning and budgeting were widely practiced by the farmers. Out of the 25 farmer-respondents who availed of loan, 21 of them monitored the status of their loans. More than half of them also practiced financial planning and budgeting of their income and loan. The multiple linear regression analysis revealed that monitoring financial budgets and comparing farm profitability with that of other farms or benchmarking are significantly and positively related to profitability. The logistic regression analysis showed significant relationships of household size and being able to avail credit with the relevant financial management practices. The results imply that farmers who have more household members and who have availed of credit are more likely to monitor financial budgets and/or compare profitability with other farms.

Keywords : Banana production, Farm profitability

Annals of Tropical Research 40(2):107-123(2018)

Investigating the determinants of cassava domestic supply in the Philippines

Author(s): Rhena Jane M. Soria1 and Lemuel S. Preciados1*


Cassava is a significant crop in the Philippines because of its many uses and increasing demand from feed milling industries. However, the supply for this crop in the country, compared to other ASEAN countries, remains low and relatively less competitive. There are studies suggesting the need to review factors affecting agricultural supply in the Philippines to support policy initiatives, but only a few studies were conducted specifically targeting the cassava subsector. This study tried to address these gaps. Using time-series regression analysis, this study measured the extent of the effects of the price, area, agricultural R&D expenditure, tariff rate, and weather occurrences. Results from this study suggest that farm gate price as well as area, agricultural research and development spending, and tariff rate significantly determine supply. In contrast, extreme weather occurrences such as El Niño and La Niña have negative but insignificant effect on supply. In addition, this study has also proven that the identified determinants have long run relationship with cassava domestic supply, which suggests that cassava supply cannot readily adjust to changes in these determinants. These results provide insights into how each variable would affect supply, which have certain implications to policy such as the adoption of specific price policy intervention like price support schemes that safeguard farmers’ income against price fluctuations.

Keywords : time series analysis, short run, long run, supply response

Annals of Tropical Research 40(2):90-106(2018)

Determinants of corn farmers to adapt to climate change impacts in Sagbayan, Bohol, Philippines

Author(s): Zyra May H. Centino* and Arvin B. Vista2


The need to adapt to the negative impacts of climate change is urgent especially in the agriculture sector. However, there have been no published reports whether upland corn farmers are applying climate change adaptation strategies. This study sampled 91 upland corn farmers in Sagbayan, Bohol, Philippines to determine the factors affecting their decision to employ adaptations strategies. The adaptation strategies are those soil and water management and conservation techniques employed by farmers, which is modelled using binary logistic regression. The average age of the respondents was 56 years old. Respondents have been in corn production for an average period of 30 years. More than 50% of their annual household income comes from farming (PhP 25,393). Results showed that gender, farm income, total land used in farming and value of farm assets were the determinants of farmers’ use of adaptation strategies. Overall, corn farmers are knowledgeable of the impacts of climate change; however, employment of adaptation strategies is minimal. Hence, intervention should focus on programs that will increase probability of farmers employing adaptation strategies. Such programs may include farm-to-market roads to minimize post-harvest losses, setting of farmer field school and information drive.

Keywords : adaptation strategies, climate-induced impacts, upland corn farmers, soil and water conservation

Annals of Tropical Research 40(2):77-89(2018)

Potential of Seriales, Flacourtia jangomas (Lour.) Raeusch, fruit for wine production

Author(s): Lynette C. Cimafranca1* and Erlinda I. Dizon2


Flacourtia jangomas, locally known as seriales, is one of the indigenous tree species in the island of Leyte, Philippines that is neglected and underutilized. To maximize its utilization, the potential of the commodity for wine-making was explored using the Placket-Burman (PB) experiment, which was carried out to identify the most significant factors affecting the quality of the wine. There were seven variables (n=7) identified, namely; fermentation temperature, contact time, sugar level, dilution, microbial strain and two dummy variables with a total of eight runs. Results show that fermentation temperature, contact time, sugar level and microbial culture significantly affected the sensory quality of seriales wine.

Keywords : Seriales, Flacourtia jangomas, Plackett-Burman Design, Wine

Annals of Tropical Research 40(2):69-76(2018)

Selection of lactic acid bacteria for exopolysaccharide production

Author(s): Ivy C. Emnace1* and Erlinda I. Dizon2


An important source of natural alternative to commercial additives that are commonly extracted from plants and animals is the exopolysaccharide (EPS) produced by lactic acid bacteria (LAB). A screening for EPS production by Lactobacillus delbrueckii, Lactobacillus rhamnosus NBRC 3425 and Weisella paramesenteroides was conducted to identify which among these three LAB would produce the highest yield of EPS. The test organisms were grown in a Semi-defined Medium (SDM) of Sanchez et al (2006) with some modifications. EPS production was confirmed by the formation of precipitate after mixing the broth medium with 95% absolute ethanol. Results of total sugar analysis by phenol-sulfuric acid assay revealed that estimated EPS yield of L. rhamnosus NBRC 3425 was significantly higher at p<0.05 than those of W. paramesenteroides and L. delbrueckii ssp. lactis with values of 0.1355g/L, 0.0652g/L and 0.0544g/L, respectively even though their viable count did not differ significantly from each other. Correspondingly, the pH of L. rhamnosus NBRC 3425 media was also significantly higher (pH 4.03) than L. delbrueckii (pH 3.60) and W. paramesenteroides (pH 3.83).

Keywords : exopolysaccharide, lactic acid bacteria, phenol-sulfuric acid assay, Semi-defined medium (SDM), total sugar

Annals of Tropical Research 40(2):61-68(2018)

Occurrence and variation of calcium oxalate crystals in selected medicinal plant species

Author(s): Alyssa Faye Z. Capacio and Beatriz S. Belonias*


Calcium oxalate (CaOx) crystals are microscopic mineralized particles found in over 215 plant families of plants. In this study, the occurrence and variation of CaOx crystals in 15 different species of commonly used medicinal plants were investigated. Information on the type and other characteristics of CaOx crystals present in medicinal plants is important considering the potential health risks posed by these crystals to humans and other animals, aside from the fact that crystal characteristics are also valuable in the taxonomic identification of plant taxa. Results showed that eight of the 15 species, namely; Abelmoschus esculentus, Acalypha indica, Amaranthus viridis, Basella alba, Bixa orellana, Codiaeum variegatum, Ipomoea batatas, and Jatropha podagrica produced druses. Only four species formed raphides and these were Bougainvillea spectabilis, Cordyline fruticosa, Impatiens balsamina, and Rhoeo spathacea, although styloids were also observed in Cordyline fruticosa. Prismatic crystals and crystal sands were the least common, the former produced only in Chorchorus olitorius and Senna alata, and the latter only in Solanum melongena. The raphides of B. spectabilis were the longest at 175.81µm while the druses of B. orellana were the smallest having a mean diameter of 16.72µm. In terms of density, C. olitorius and S. alata had the highest number of crystals per unit leaf area.

Keywords : calcium oxalate crystals, raphides, druses, styloids, prismatic crystals, crystal sands, medicinal plants

Annals of Tropical Research 40(2):45-60(2018)

Chlorophyll content of Thalassia hemprichii (Ehrenberg) Ascherson leaves in some coastal areas of Cebu Island, Central Philippines

Author(s): Lorenzo C. Halasan* and Danilo T. Dy


Variations in the chlorophyll concentrations in seagrass leaves can be used to indicate biomass, productivity and overall ecosystem condition in coastal areas. In this study, we determined the chlorophyll content (ie chl a and b) of Thalassia hemprichii from selected coastal areas in Cebu Island, Central Philippines to determine if there were spatial variations between intertidal (0m) and subtidal (1.5m) sections, and in the five geographically separate coastal areas of the island. Pigment extraction was done using 95% acetone, the solution analyzed via spectrophotometry and quantified using the equation of Ritchie (2006). The values were statistically compared using nonparametric tests. Mean chlorophyll content and chlorophyll a/b ratio of T. hemprichii showed no significant variations between intertidal and subtidal sections: F(4,45)=27.75, p=0.192 for mean chlorophyll content and F(4,45)=18.28, p=0.116 for chlorophyll a/b ratio. However, there was significant difference between geographic areas (p=0.000). Although T. hemprichii tend to display a physiological response to shading and light limitation, the difference in depth (≈ 1.5m) between intertidal and subtidal sections did not produce a statistically meaningful difference. However, the significant differences between sites for the chlorophyll content and chlorophyll a/b ratio of T. hemprichii could guide future decision in seagrass transplantation of specific localities.

Keywords : chlorophyll a/b ratios, seagrass health, bioindicator of coastal pollution, spatial variation, Philippine reefs

Annals of Tropical Research 40(2):35-44(2018)

Courtship duet between the female and the male Aedes aegypti queenslandensis (Theobald) (Diptera: Culicidae) under laboratory conditions

Author(s): Elaisa Mae M. Jamora1*, Zaira Isabelle M. Gines1, Claude Ceniza2, Rommel G. Bacabac2
and Frances E. Edillo1


This study aimed to determine the wing beat frequencies and spherical spreading between the female and the male Aedes aegypti queenslandensis during courtship under laboratory conditions. The field-collected larvae and pupae were reared into adult mosquitoes and were morphologically identified. Male and female individuals were coupled. Second generation of live adult mosquitoes were tethered to a stainless wire in their upright position and flight tones produced by their wings were recorded using pressure-gradient microphones. Results showed that the fundamental wing beat frequencies of male mosquitoes (607-1,037Hz) were higher than those of the female (487-660Hz). The different distances between male and female mosquitoes did not influence their wing beat frequencies (p>0.05). Wing beat frequencies of male mosquitoes differed significantly when paired with the female, in all distances between them (p<0.05), whereas those of females, did not differ (p>0.05). Thus, the male Ae. aegypti queenslandensis adjusted and converged with the female’s flight tone. Convergence was restricted to the fundamental frequency for all distances except at the 19-cm distance between them, where convergence happened in the harmonics. Analysis on the spherical spreading on their wing beat frequencies did not differ significantly (p>0.05) in six locations of the microphones relative to the mosquitoes, thus, mosquitoes’ flight tone moved in a spherical manner and that courtship could happen in different directions. Results are relevant for mosquito control by developing an acoustical device to disrupt their courtship.

Keywords : Aedes aegypti queenslandensis, dengue, wing beat frequency, spherical spreading, phase difference

Annals of Tropical Research 40(2):15-34(2018)

Lead potential bioaccumulation in two species of commonly used medicinal plants in Leyte

Author(s): Honeylene V. Ongy* and Beatriz S. Belonias


Medicinal plants, especially those that are grown and cultivated in heavily polluted soils, are one source of lead toxicity in humans. This study assessed the Pb accumulation capacity of two commonly used medicinal plants, Artemisia vulgaris and Plectranthus amboinicus. Bioaccumulation factor, translocation factor and metal extraction ratio of each plant species were also determined. The plants were planted in pots in a controlled experiment and subjected to different concentrations of Pb (0–600ppm) for 4 weeks. Both plants showed no visual signs of Pb toxicity at the end of the study. The growth of A. vulgaris was not significantly affected by the different levels of Pb added to the soil. The increase in height of P. amboinicus was significantly affected by the Pb in the soil. The roots accumulated more Pb, followed by the leaves and the stems. Pb level in plant tissues increased with increased addition of Pb to the soil. Bioaccumulation factor (BAF) of A. vulgaris and P. amboinicus was above 1 which means these plants are accumulators of Pb. With a translocation factor (TF) > 1, A. vulgaris can effectively transfer Pb from the stems to the shoots while P. amboinicus cannot. Of the two plants, P. amboinicus was most effective in removing lead from the soil even at high concentrations (600ppm).

Keywords : bioaccumulation factor, metal extraction ratio, translocation factor, lead, medicinal plants

Annals of Tropical Research 40(2):1-14(2018)