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September 2021 – Vol. 104 No. 3

Pummelo, ‚pomelo‛ or ‚shaddock‛, is a popular citrus variety widely grown and consumed in the country and has grown as an essential commodity in international markets. In this paper, Thrips hawaiiensis (Morgan) was the only species of thrips infesting ‚Magallanes‛ Pummelo (Citrus maxima Burm.). Significantly high population of Thrips hawaiiensis at the peak of flowering stage and fluctuated at petal and fruit developmental stages. Flowers including terminal shoots provided stable food sources for T. hawaiiensis.


Will patients benefit from the current Philippine Legislative Bill on Medical Cannabis? A Cost-Benefit Analysis
Emmanuel S. Baja, Paul Joseph B. Ramirez, Godofreda V. Dalmacion, and Zypher Jude G. Regencia

Received: July 09, 2020/ Revised: May 04, 2021/ Accepted: June 25, 2021

Philippine Congress is pushing House Bill (HB) 6517 to decriminalize medical cannabis use in the Philippines. This study aims to evaluate the cost and benefit that will likely result from the legalization of medical cannabis. Focus group discussions, key informant interviews, and review of secondary data were done with stakeholders to validate and localize the benefits and costs associated with the legalization of medical cannabis versus the current status quo. Cost-benefit analysis (CBA) was based on the requirements of HB 6517. Only direct effects on major stakeholders were covered in the final CBA. Results were expressed as Net Present Value (NPV) to society. Medical cannabis legalization in the Philippines will yield a positive NPV to society but will take approximately 14 years before benefits for both the government and patients can be realized. More than 90% of the total benefit goes to patients, and < 10% goes to the government. In terms of economic viability, NPV turns positive once benefits are realized. The return on investment will be at 60% by the 14th year of implementation, with a 10% projection of benefits going to the government in taxes and net income. Based on projected simulations, Filipino may benefit from the legalization of medical cannabis.

Genetic Diversity and Population Structure of Sugarcane (Saccharum officinarum L.) Collected from Seven Philippine Regions for Use as Breeding Stocks for Crop Improvement
Jan Leandro L. Acedera, Jhun Laurence S. Rasco, Jemimah C. Banganan, and Antonio G. Lalusin

Received: January 06, 2021/ Revised: May 26, 2021/ Accepted: August 08, 2021

Selection of parents for hybridization relies on the information on their genetic relationship and diversity which are essential in any breeding program. This study aimed to estimate the extent of genetic diversity and population structure of 76 sugarcane accessions from seven regions in the Philippines using 57 morphological characters and 50 microsatellite markers. The sugarcane collections exhibited moderate to high diversity with mean of H’ = 0.72 for qualitative and H’ = 0.75 for quantitative morphological characters, respectively. This is corroborated by the analysis of variance (ANOVA) of agronomic parameters, except for stalk length. Unweighted Pair Group Method with Arithmetic Mean (UPGMA) cluster analysis based on morphology subdivided the accessions into 31 clusters which reveal phenotypic variability among sugarcane samples. The fingerprints of the 76 accessions were also evaluated using 45 Saccharum-based genomic SSR and 5 EST-SSR primer pairs to measure genetic diversity and population structure. Based on UPGMA, a total of six clusters were generated with a 0.65 coefficient of dissimilarity, and the sugarcane accessions were further subdivided into five major sub-populations. Out of 50 markers used, 41 (82%) were found to be highly informative with a mean PIC value of 0.69. It was also expected that Saccharum-based genomic SSRs were more polymorphic (92%) compared to EST-SSRs (82%) since the latter preferably amplify in more conserved and expressed sequences in the genome. Out of 2,850 pairwise combinations based on the Jaccard coefficient index, large diverse parental combinations (genetic dissimilarity = 0.51 – 0.70) were observed, indicating substantial diversity from the existing breeding pool of IPB-UPLB for genetic improvement. Cluster analysis based on UPGMA, STRUCTURE analysis, and Principal Coordinate Analysis (PCoA) were predominantly consistent. However, no association was observed between the geographical origin and genetic distance of the genotypes based on molecular data. The results showed that accessions were grouped into five sub-populations and genetic differentiation within sub-population was higher (85%) as compared to between sub-population (15%) based on the analysis of molecular variance (AMOVA), suggesting an active exchange of genetic pool across provinces and regions of both Luzon and Visayas islands. The findings from this study will be useful for future breeding efforts by exploiting genetic variation existing in the current breeding population.

Identity and Population Density of Thrips hawaiiensis (Insecta: Thysanoptera) in Conventional “Magallanes” Pummelo Orchard in Carmen, Davao del Norte, Philippines
Roderick M. Granada, Flor A. Ceballo, and Pio A. Javier

Received: August 22, 2019/ Revised: August 20, 2021/ Accepted: August 26, 2021

A conventional “Magallanes” Pummelo orchard in Brgy. Minda, Carmen, Davao del Norte, Philippines was selected to assess thrips species composition, population density, and associated natural enemies. The insecticide treated pummelo orchard was situated adjacent to vast Cavendish banana plantations. Thrips were collected weekly from September 2017 to July 2018 from five different randomly selected flowering pummelo trees by destructive sampling and yellow sticky trap methods. Thrips were sorted and examined under the microscope. Findings of the study showed that Thrips hawaiiensis (Morgan), (Thripidae: Thripinae) was the only species of thrips infesting “Magallanes” pummelo. This constitutes the first report in this host variety. Thrips hawaiiensis population fluctuated within the six phenological stages of pummelo fruiting cycle but was significantly high at the peak of flowering stage. Population started to decline at petal fall and fruit development stages although the pummelo still produced small numbers of new terminal shoots. These shoots provided stable food source for remaining thrips larvae. Population was significantly low when the fruits are at harvestable stage (p < 0.01). Among the weather variables monitored temperature had very low coefficient value (r = 0.09) with a positive relationship to thrips population; however, together with rainfall and relative humidity, statistical significance value did not significantly (p > 0.05) influence thrips population. Furthermore, absence of parasitoids during the whole duration of the study may have been affected by the conventional pest management continuously being practiced by plantation owners of using broad spectrum insecticides that may have affected the non-target species in the area.

Efficacy Study of Selected Maize (Zea mays L.) Genotypes Against the Asian Corn Borer, Ostrinia furnacalis (Guenée)
Yoryncita C. Marfori, Merdelyn T. Caasi-Lit, and Tonette P. Laude

Received: March 11, 2020/ Revised: February 24, 2021/ Accepted: July 15, 2021

Laboratory and screen house studies were conducted to assess the efficacy of selected twenty-six maize varieties against Asian corn borer (ACB), Ostrinia furnacalis (Guenée). Hierarchical tree based on resistance parameters clearly revealed that the twenty-six maize varieties are best classified into three groups, viz. resistant, intermediate, and susceptible. In laboratory test, the varieties RCS2, RCS4, RCS5, ‘IPB Var13’, Bt2, Bt3, and Bt4 were consistently identified as highly resistant. Further examinations in stalk feeding assay showed that the resistant varieties had sharp decline in larval survival (LS) on the 2nd to the 5th day of larval feeding in stalk tissue. On the other hand, the susceptible varieties showed high LS across the 5-day feeding duration. This research highlighted that resistant maize varieties were mainly attacked below the ear nodes and internodes, with the most frequent observation on the 8th node below the ear node but had zero attack on the crucial ear node. Meanwhile, both the intermediate and the susceptible varieties were attacked on the ear node, with the feeding attacks distributed throughout the whole plant. This research provided further evidence that ACB resistance is available in Philippine native maize varieties. These experiments corroborate with previous results that transgenic maize expressing the Cry1Ab protein is lethal to ACB larvae. High resistance observed from the non-Bt ‘IPB Var13’ suggests that natural resistance is present. This research have presented that Bt varieties (Bt2, Bt3, Bt4) together with RCS2, RCS4 and ‘IPB Var13’ were the consistently resistant varieties in both laboratory and screen house assays. The plant resistance indices used in this study can effectively screen different varieties of maize in the Philippines. Further experimentations would be needed to determine the mechanism involved in the resistance and susceptibility of maize varieties infested with ACB.

Optimization of Ethanol Production from Enzymatically Saccharified Biomass of Acid-Pretreated Rice Straw
Muzammal Mateen Azhar, Qurban Ali, Arif Malik, Elham Khalili, Muhammad Arshad Javed, Shinawar Waseem Ali, and Muhammad Saleem Haidar

Received: January 10, 2021/ Revised: June 01, 2021/ Accepted: August 05, 2021

The substrate of rice (Oryza sativa) straw employed in this study was procured from local market and stored in polyethene bags until needed. The study was conducted to find out the effects of process optimization of ethanol production from enzymatically saccharified biomass of acid-pretreated rice straw. The results indicated that acid pretreatment has reduced lignin content about 50%. Resultantly, pretreatment raised cellulose contents up to 52% making it suitable for enzymatic saccharification. Optimization of saccharification illustrated that parameters such as biomass, enzyme concentration, temperature, incubation time and agitation indeed affected the action of cellulase on pretreated biomass releasing sugars up to 31.0 g/L. The results clearly indicate the need for optimization at every point in the ethanol production process for efficient use of resources and maximum yield without wastage. Among various operational modes of fermentation studied, such as batch, semi-continuous and continuous, the semi-continuous process gave better ethanol yield of 23.4 g/L. This implies potential use of the process in industrial grade ethanol production. Collectively, the study has shown that rice straw can serve as a lignocellulosic substrate, utilizing acid pretreatment for cellulose exposure and enzymatic saccharification to release fermentable sugars for production of ethanol.

Isolation and Characterization of the Total Protein in ’Lakatan’ Banana (Musa acuminata Colla) with Bioactive Peptides Exhibiting Antioxidative and Antihypertensive Activities
David Mangussad, Ana Teresa Sucgang, Mia Clare Marie Clemencia, Marlon Manalo, Lawrence Yves Uy, and Mary Ann Torio

Received: November 30, 2020/ Revised: August 13, 2021/ Accepted: August 16, 2021

Hypertension is leading cause of disease burden in developing countries. Leading factors are obesity, increased cholesterol levels, and long-term oxidative stress. Since commercially available drugs for cardiovascular diseases such as antioxidants and ACE receptor blockers are expensive, preventive cheaper alternatives derived from foods are sought after. Lakatan, one of the most abundant and cheap food sources in the Philippines has been proven to have antioxidant and antihypertensive properties but studies exploring the proteins and bioactive peptides responsible for its health benefits are very limited. In this study, proteins from Lakatan (Musa acuminata Colla) have been studied to understand the components of banana that gives its health benefits. In silico analysis was done to determine the presence of bioactive peptides. Results showed that a 14.697 kDa lectin may release antioxidative and antihypertensive peptides upon digestion. Isolation of the crude/total protein of “Lakatan” banana (Musa acuminata) flesh was done using 500 mM Tris-Cl, pH 8.0, 100 mM KCl, 2% polyvinylpolypyrrolidone (PVPP). The protein concentration of the crude/total protein was determined using Lowry assay and results showed a value equal to 0.865 mg/mL ± 0.052 mg/mL. The crude/total protein was subjected to proteolytic digestion using pepsin, trypsin, chymotrypsin, and thermolysin as enzymes for 3-, 12-, and 24 – hours digestion time. Using densitometric analysis, complete digestion has occurred after 24 hours of digestion time. The crude/total proteins and digests were subjected to antioxidative assay using 2,2-diphenyl1-picrylhydrazyl (DPPH) and spectrophotometric Angiotensin-Converting Enzyme (ACE) inhibition assay. Results of the DPPH assay showed the highest antioxidative activity of 54.00% from the undigested crude/total proteins. Among the different digests, the 12 h digest (38.60%) had the highest antioxidative activity. Results of the ACE assay showed the highest inhibition (43.03%) after 24 h digestion time. These study shows that Lakatan has the potential to be a cheap source of antioxidants and antihypertensive functional food which can be further explored for drug discovery and development.

Spectral Lights Based Treatment Enhanced Biomass Accumulation and Secondary Metabolites Production in Callus Culture of Citrus Reticulata
Faiza Anum, Naveed Iqbal Raja, Tahira Sultana, Abeer Kazmi, Amir Ali, Bushra Qayyum, Anza Afzal, Aneela Nijibat, and Zia-ur-Rehman Mashwani

Received: April 05, 2021/ Revised: July 27, 2021/ Accepted: July 29, 2021

Citrus reticulata is a common fruit, belongs to the family Rutaceae. It contains terpenes, phenolics, flavonoids, and vitamin C in conjugation with sugars, amino acids, minerals, organic acids and other biologically important compounds. Application of light elicitation strategies in in vitro plant cultures is acquiring more interest for their potential in feasible biomass accumulation and therapeutically important secondary metabolites production. The present study was designed to investigate the effects of different monochromatic lights (white, red, blue, green, and yellow) on the proliferation and secondary metabolites accumulation in callus cultures of Citrus reticulata raised in response to treatment with AgNPs and TDZ. Silver NPs were synthesized by using green method, followed by characterization of these NPs. Nucellus tissues obtained from seeds of C. reticulata and inoculated on MS medium supplemented with TDZ (1 mg/L) + AgNPs (20 ppm) for callus development. To examine the effects of different light spectrum, the developing calli was sub-cultured on similar media and incubated in growth chamber under five different light treatments (white, red, blue, green, and yellow). Total protein content, chlorophyll content, phenolic and flavonoid content, along with activity of antioxidant enzymes on all samples was also analyzed. Highest callus fresh weight (730.21 mg) was recorded in callus cultures proliferated under white light condition. Phytochemical analysis of callus cultures showed significantly higher values for TPC, TFC and antioxidant activity under red light. However, maximum production of anti-oxidative enzymes (SOD and POD) was recorded under blue light. White light is considered more favorable for accumulation of total protein content. To our knowledge, this is the first study on production of biomass and phytochemicals in response to different monochromatic lights in callus cultures of Citrus reticulata. The present research outcomes clearly exhibited the interest to apply monochromatic light as elicitor of in vitro callus cultures to promote the production of biomass and important bioactive metabolites.

Drift Reduction by Orienting Boom Sprayers’ Nozzles Against the Wind Direction
Medet İtmeÇ, Ali Bayat, and Ömer Barış ÖzlÜoymak

Received: December 14, 2020/ Revised: July 14, 2021/ Accepted: August 20, 2021

Wind drift is a very critical issue in pesticide applications. In recent experiments, the application of pesticides is focus on precision farming. In this study, a spraying system that could manipulate trajectories of droplets to decrease drift was tested in a wind tunnel. Three nozzles (XR11002, AIXR11002 and TTJ6011002) were used at three operating pressures (200 kPa, 300 kPa, 400 kPa), with four orientation angles of nozzles against wind direction (0°, 5°, 10°, 15°), and three wind velocities (1.5 m s-1, 2 m s-1 and 2.5 m s-1) with three repetitions. A statistical factorial CRD was used with Tukey Post Hoc Test to determine the significance of the differences between treatment means. The results from the experiment showed that the downwind drift as spray pattern displacements were significantly reduced in the angled position of the nozzles compared to the non-angled position. The highest downwind drift reductions were achieved with AIXR11002 (38.47%) under conditions of 200 kPa pressure, 2 m s-1 wind velocity and 15° orientation angle. and for TTJ6011002 (34.41%) under conditions of 200 kPa pressure, 1.5 m s-1 wind velocity and 15° orientation angle. Even the XR11002 nozzle, which had the highest drift potential among selected nozzles achieved about 22.56% downwind drift reduction at 200 kPa pressure, 2 m s-1 wind velocity and 10° orientation angle.

An Evaluation of the Hargreaves-Samani Method for Estimating Evapotranspiration Under Semi-Arid Conditions
Yusuf Aydin

Received: February 19, 2021/ Revised: August 31, 2021/ Accepted: September 02, 2021

It is suggested by the Food and Agriculture Organization of the United Nations (FAO) to use the FAO56-Penman-Monteith (FAO56-PM) model as the standard model in reference crop water consumption studies. However, the climate parameters required by the standard model cannot be fully and reliably obtained in under developed or developing countries. Hence, the Hargreaves-Samani (HS) equation is used as an alternative to the FAO56-PM model since it can be used for calculations with less climate data. In the present study, ETo-PM and ETo-HS values calculated at 8 provinces in Southeastern Turkey using the IAM-ETo software were evaluated and compared in order to examine whether the HS equation can be alternative to the FAO-PM equation or not. It was observed at the end of the study that the daily calculated ETo-HS values yielded 16% overestimation on average compared with ETo-PM. Statistically highest (RMSE: 1.32, MAE: 1.10, MR: 1.37, and PE: 36.86) and lowest (RMSE: 0.33, MAE: 0.24, MR: 0.96, and PE: 5.32) values were calculated for Batman and Mardin respectively. The mean values for the Southeastern Anatolia Region were calculated as RMSE: 0.64, MAE: 0.52, MR: 1.17, and PE: 16.04. It was identified in the light of these findings that the HS equation can be used as an alternative to FAO56-PM for the studied provinces.

Research Note

Effects of Copper Oxide (CUO) and Zinc Oxide (ZNO) Nano and Bulk Forms to Soil Fungal Community
Jonathan Jaime G. Guerrero, Teresita U. Dalisay, Nolissa D. Organo, and Ireneo B. Pangga

Received: July 17, 2019/ Revised: July 16, 2021/ Accepted: July 22, 2021

The effects of copper oxide (CuO) and zinc oxide (ZnO) in bulk and nano forms on soil fungal community was determined. Lipa clay loam soil collected from the University of the Philippines Los Baños were placed in polypropylene bags and amended with 300 mg/L of CuO or ZnO in either forms. Colony-forming units (CFU) as well as average well color development (AWCD), functional richness and stress index were determined on day 1, 8 and 15 via indirect viable plate count method and community – level physiological profiling (CLPP). Fungal isolates from the same soil samples were likewise identified and tested in vitro in terms of radial growth when treated with varying concentrations of the metal oxides. Results indicated no significant difference in CFU, AWCD, functional richness and stress index among treatments. In vitro, responses of fungal isolates differed. CuO was more toxic than ZnO. In both cases, the nature of the compound, not size, was the primary determinant of toxicity. It is recommended that the use of nanotechnology in agriculture be promoted with caution to limit the harmful effects to the soil microbiota and to the environment in general.

Epiphyte Identification on Commercially Grown Kappaphycus alvarezii in Eastern Samar, Philippines
Ma. Carla Angelica E. Deladia, Leni G. Yap-Dejeto, Kenneth Abuda, Rey Verona, and Margarita Dela Cruz

Received: May 03, 2020/ Revised: August 16, 2021/ Accepted: August 24, 2021

The decline in production and quality of Kappaphycus alvarezii is primarily associated with occurrence of “ice-ice” disease and epiphyte infestations. K. alvarezii var. tambalang (brown) in the nursery farms of Balangiga and Lawaan, E. Samar harbored such infestations. This study identified the dominant Epiphytic Filamentous Algae (EFA) on the seaweeds in these farms using microscopic morphological characteristics. Microscopic examinations revealed that the main epiphyte in the farms studied was Melanothamnus apiculatus (Hollenberg) Díaz-Tapia & Maggs (former: Neosiphonia apiculata (Hollenberg) Masuda et Kogame). The epiphytes observed have rhizoids separated from the pericentral cells, unicellular trichoblasts, globose cystocarp and tetrasporangia arranged in spiral series, with four pericentral cells and tapered apex with trichoblasts. Epiphyte percent cover was higher in Balangiga (17 ± 11.3%) than in Lawaan (3.6 ± 3.98%). The intensity of ice-ice disease remained low for both sites. The physico-chemical parameters measured, temperature, salinity, depth, turbidity and nutrients were within normal range; except for the recorded 19°C temperature in Balangiga which was below the range recommended for optimal growth of Kappaphycus. This may explain the higher epiphyte cover in Balangiga than in Lawaan.

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