LIST OF ARTICLES
Mussaenda ‘Dolores A. Ramirez’ is a hybrid variety named in honor of the National Scientist Dolores A. Ramirez for her outstanding contributions to the field of genetics. It is an outstanding selection with profuse inflorescence from a cross between M. ‘Maria Makiling’ x M. ‘Doña Trining’. Even during the dormant months, this mussaenda hybrid continues to bloom and does not tend to droop at the peak of flowering. The mussaenda hybrid variety is a part of the Outstanding Women Breeder Series from the UPLB.
Biology of Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae) on Rice and Different Corn Varieties
Anthony S. Agravante, Karen B. Alviar, Analiza Henedina M. Ramirez, and Sheryl A. Yap
Received: October 6, 2021/ Revised: October 10, 2022/ Accepted: October 26, 2022
Rice and corn are one of most important crops in the Philippines. Several insect pests contribute to the losses and low yield of these crops. The fall armyworm (FAW), Spodoptera frugiperda (J.E. Smith) was reported recently to cause economic damage to corn. Also, this insect consists of two genetically differentiated strains, the corn strain and the rice strain. This study was conducted under laboratory conditions to evaluate the biological parameters of FAW on rice and different corn varieties. Newly hatched larvae were fed open pollinated variety (OPV), traditional variety, Macho F1 (hybrid), NK 6410 (genetically modified organism), and rice variety, RC 226. Duration of larva, prepupal, pupal, and larva-adult period, pre-oviposition, oviposition, and post-oviposition period, number of egg mass, fecundity, sex ratio, and survivability of larva to adult of different crops were evaluated. The results showed that the duration of development from egg to adult in Macho F1 and NK 6410 with an average duration of 24.58 and 24.66 d was significantly shorter than on OPV, traditional variety and rice variety, RC 226. The number of eggs laid by females reared on Macho F1, NK 6410, and OPV, with a mean of 1125.60, 1176.80, and 1049.40, respectively, were significantly greater than the traditional variety, tinigib and rice RC 226. Different corn varieties and rice did not affect the male and female ratio, longevity, and survivability. The results of this study will provide insights into formulating management strategies for fall armyworm.
Susceptibility of Pre-adult Biological Stages of Mythimna separata (Walker) (Lepidoptera: Noctuidae) to Three Entomopathogenic Fungi (Hypocreales)
Melissa P. Montecalvo and Marcela M. Navasero
Received: August 16, 2022/ Revised: January 25, 2023/ Accepted: January 26, 2023
Armyworms are polyphagous insect pests of agricultural crops. Their population is usually managed below threshold level using insecticides. However, a single control measure is insufficient to attain a sustainable pest management. Hence, this research was conducted to assess the three species of entomopathogenic fungi as potential biological control agents against Mythimna separata (Walker) or paddy armyworm. Dose mortality assays were conducted to determine the pathogenicity of Beauveria bassiana (Bals.) Vuill., Metarhizium anisopliae (Metschn.) Sorokin, and Metarhizium rileyi (Farlow) Kepler, S.A. Rehner and Humber against various biological stages of M. separata including egg, 1st to 6th larval instars, prepupa, and pupa. These entomopathogenic fungi did not have ovicidal activity but affected the survivorship of the resulting neonates. Exposure of eggs to B. bassiana, M. anisopliae, and M. rileyi infected 64, 60, and 70% of the resulting neonates, respectively. Adult emergence was also reduced in fungal-treated (29% in B. bassiana, 10% in M. anisopliae, and 10% in M. rileyi) as compared with 64% in control. At 7 d after treatment, M. rileyi applied at 1 x 105 to 1 x 109 conidia/mL was the most pathogenic causing a mean larval mortality of up to 70% as compared to B. bassiana and M. anisopliae with less than 10% mortality. Among the larval instars, the 1st, 2nd, and 3rd were the most susceptible to fungal infection. Conidial concentrations (1 x 108 and 1 x 109 conidia/mL) induced the highest larval mortalities as compared to the lower conidial concentrations (1 x 105 and 1 x 107 conidia/mL) of the entomopathogenic fungi. The prepupal and pupal stages were also slightly susceptible to the entomopathogenic fungi. These findings showed the pathogenic effect of the entomopathogenic fungi particularly M. rileyi to M. separata.
The Use of Open Data Kit (ODK) in Characterizing the Cacao Industry Sites in Panay Island
Rhea J. Subong, Reynold D. Tan, and Christine Mae D. Hernando
Received: February 28, 2022/ Revised: September 23, 2022/ Accepted: October 5, 2022
Cacao is one of the world’s most valuable export commodities and cash crops. Western Visayas, along with the other regions of the Philippines, has committed to participate in national efforts to strengthen the production capacity of the cacao industry and address prospects and opportunities for the industry growth and development. This paper presents the results of a region-wide study that mapped out and assessed key cacao-producing areas in the Western Visayas, specifically Aklan, Antique, Capiz, and Iloilo. The study sought their current production levels, important agricultural properties of farming areas, production densities, and growth potentials. Geospatial data was generated, analyzed, and mapped using Open Data Kit (ODK), an electronic data management system. Findings revealed that cacao plantations are not evenly distributed in Panay Island. Most cacao farms are located in the Province of Iloilo; however, tree density was highest at farms in the Province of Capiz. The geophysical characteristics of most cocoa-producing areas were consistent with the geophysical elements mentioned in the literature. These findings can be used for science-based decisions for promoting the emerging cacao industry in Panay Island.
Evaluation of Some Toxic Trace Elements in Crocus sativus L. and Soil Using Neutron Activation Analysis Technique
Ehsan Taghizadeh Tousi
Received: July 15, 2020/ Revised: November 2, 2022/ Accepted: November 24, 2022
Neutron activation analysis was used in this research to measure the concentrations of aluminum (Al), bromine (Br), chlorine (Cl), mercury (Hg), arsenic (As), and thorium (Th) in soil and saffron plants as well as their contamination, enrichment, and translocation rates. The edible part of the saffron showed a higher Hg concentration than the WHO/FAO-permitted level in the urban area. The soil was not intoxicated and contaminated by Al, As, and Th except in the urban areas, which were slightly polluted by As. The calculated contamination degree and pollution load index indicated that the soil was almost uncontaminated. The enrichment factors (EF) showed minimal enrichment levels of Al and Th and low As contamination, which may still increase due to human activities in the environment. The tested elements’ translocation abilities were also evaluated by the paired t-test statistical method and indexes of translocation, and it was found that Al, As, and Th can quickly relocate into different soil depths. Saffron was also evaluated as a very poor absorber of the elements studied. While Cl and Th can easily move from the saffron’s corm to its aerial parts, Al and Hg merely translocate from the corm to the petal. It was also found that Al, Cl, and Th can move between the petals and the thread.
Spray Characterization of an Unmanned Aerial Vehicle for Agricultural Spraying
Eray Önler, Hasan Berk Özyurt, Mehmet Şener, Sezen Arat, Bülent Eker, and İlker Hüseyin Çelen
Received: January 14, 2022/ Revised: October 10, 2022/ Accepted: November 20, 2022
Sustainability and higher efficiency in crop production are possible with the use of new technologies. The use of unmanned aerial vehicles brings many advantages both in terms of monitoring agricultural areas and pesticide applications. This technology allows us to detect diseases and damages in an early manner and apply them in areas that are not accessible by conventional sprayers. However, a lack of knowledge on how to use UAVs and what parameters need to be considered prevent the widespread use of drone technology in agriculture. This study established parameters for spraying with clean water using a DJI Agras 14 MG-1P (RTK) Unmanned Aerial Vehicle. Droplet distribution and droplet analyses were examined in the studies carried out at different heights (1.5, 2.0, and 2.5 m) and flow rates (10, 15, 20, 25, and 30 L/ha). Droplets were analysed using DepositScan. Coefficients of variation of droplet distribution tend to decrease with the increasing spray rate. The trials with the closest values to uniformity are spraying applications made with a flight height of 2 m. When we evaluate pesticide efficacy according to the number of droplets per unit area, insecticides and all herbicides can be effective at applications with flight heights of 1.5 and 2 m and spray rate of 20 L/ha. While all spraying is done with flight heights of 1.5 and 2 m and spray rates of 25 L/ha, fungicides are ineffective when applied from 2.5 m height. As a result, this study found the measurements made at 2 m altitude and 20 L/ha spray rate have the highest coverage rate and lowest drift potential.
Effects of Drying Temperature and Tempering Duration on Hybrid Rice Seed Germination, Thin-Layer Drying Characteristics, and Power Requirement
Rina A. Bawar, Joanne P. Foliente, Kevin F. Yaptenco, and Mitchie Ann L. Cabiles
Received: June 29, 2022/ Revised: January 23, 2023/ Accepted: March 23, 2023
This study presents the results of thin-layer drying tests for hybrid rice seeds. The independent factors were drying air temperature (45, 55, and 65 °C) and tempering duration (1, 2, and 4 h), while the dependent parameters were seed germination and drying characteristics, including drying rate, total and effective drying operation times, and power requirement. Considering one hybrid and a 3 mo storage period after drying, results showed that samples continuously dried at 45 and 55 °C resulted in 91 and 86% germination percentages, respectively, which were above the acceptable Philippine national standard of at least 85%. However, when tempered for 2 or 4 h, even samples dried at 65°C resulted in more than 90% germination percentage. Tempered samples had an effective operation time of only 1 – 3 h, which was 50% less than those continuously dried (1.5 – 6 h of effective operation time). In effect, the total power used was halved by applying tempering. These results showed considerable advantages of tempering in terms of seed quality improvement and potential energy savings.
Grow-out Culture of Oyster Magallana bilineata (Röding, 1798) Using Pouches: A Comparison of Growth and Survival in the River and Earthen Pond
Ma. Junemie Hazel L. Lebata-Ramos, Ellen Flor D. Solis, and Mark Jude C. Almeida
Received: October 6, 2022/ Revised: December 21, 2022/ Accepted: January 30, 2023
Oysters are among the most in-demand aquaculture commodities in the Philippines and worldwide. With the decreasing culture area and the deteriorating water quality of oyster beds, there is a need to explore new culture sites and techniques to address the problems of dwindling stocks and the increasing demand for better quality oysters. This study compared the growth and survival of the oysters Magallana bilineata, the new accepted name of Crassostrea iredalei, cultured in an earthen pond and the river using pouches suspended from rafts. Mean growth rates of oysters in length and weight were significantly higher in those reared in the river (0.56 ± 0.02 cm mo-1; 10.27 ± 0.42 g mo-1) than those in the pond (0.41 ± 0.03 cm mo-1; 5.99 ± 0.22 g mo-1), but the meat yield of oysters reared in the river (25.96 ± 0.92%) was almost the same as in the pond (24.05 ± 1.41%). Likewise, the proximate composition was the same for oysters coming from the river and the pond, respectively — 58.04 ± 0.14% and 53.86 ± 0.38% crude protein, 7.00 ± 0.08% and 7.93 ± 0.38% crude fat, 24.68 ± 0.07% and 28.54 ± 0.74% nitrogen-free extract, and 10.27 ± 0.01% and 9.68 ± 0.01% ash. Oyster survival at harvest was significantly higher in the river (70.21 ± 2.84%) than in the pond (13.10 ± 1.57%). However, with some interventions, ponds may still be utilized for oyster culture despite the low survival results in this study. Extending oyster culture in these aquaculture facilities may serve as a basis for interventions to make the pond more habitable for oysters and may help boost production in the country.
Air and Air-Steam Gasification of Coconut Shell in a Fluidized Bed
Keynty Boy V. Magtoto, Rossana Marie C. Amongo, Sergio C. Capareda, and Ronaldo B. Saludes
Received: May 11, 2022/ Revised: January 24, 2023/ Accepted: January 30, 2023
Its abundance in tropical countries, high volatile combustible matter (83.51%), and energy content (18.68 MJ kg-1) make coconut shells a good biomass resource and a promising feedstock for gasification. In gasification, different mediums such as air, steam, oxygen, or their combinations can be used to react with the solid carbon and heavy hydrocarbons of biomass. Hence, the effects of using an air-steam mixture as a gasifying agent for the bench-scale fluidized bed gasification of coconut shells were studied. The steam-to-carbon ratio (SCR) was varied to evaluate its effect on the resulting syngas quality and gasification performance while the equivalence ratio was maintained at 0.25 and the bed temperature was kept at 700°C. Results revealed that the optimum SCR is 0.6, where peak values of hydrogen (H2) and methane (CH4) content, hydrogen-to-carbon monoxide ratio (H2/CO), higher heating value (HHV), cold gas efficiency (CGE) and carbon conversion efficiency (CCE) were observed. Furthermore, the use of the air-steam mixture (SCR 0.6) as a gasifying agent was compared with the conventional air gasification. Results showed a significant increase in syngas quality in terms of H2 content (4.70–5.82%), H2/CO (0.30–0.39), and CH4 content (3.53–4.38%). The syngas heating value and gasification performance revealed statistically similar improvement: HHV from 4.95 to 5.41 MJ Nm-3, CCE from 77.64 to 81.75%, and CGE from 47.99 to 51.01%. Moreover, air-steam gasification produced less CO2 (13.42 CO2mol kgbiomass-1) and had higher energy recovery (49.67%).
RESEARCH NOTE
Validation of Newly Designed SSR Markers for Nine Rice (Oryza sativa L.) Genotypes with Variable Heat Tolerance Responses Based on Agromorphic Data and Pollen Fertility Analysis
Monaliza B. Magat, Norvie L. Manigbas, and Jessica D. Rey
Received: March 4, 2021/ Revised: December 6, 2022/ Accepted: December 13, 2022
Rice is among the most valuable staple food crops in the world. However, several challenges greatly affect production, one of which is the threat imposed by heat stress. To address this, researchers are developing varieties that are tolerant to heat stress with the aid of genetic markers. In this study, eight rice genotypes, namely Dular, Nagina 22, NSIC Rc 222, Milyang 23, EL15, EL92, EL85, and IR52 were observed for agromorphic data, which included plant height, panicle length, filled and unfilled grains, and grain yield. Flower samples were collected to determine the effect of heat stress on pollen fertility. Molecular markers were designed via in silico analysis based on the nine QTL regions distributed among five chromosomes (1, 3, 4, 5, and 10). Out of the 90 newly developed markers, Markers 3066 and 2503 showed good potential as informative markers among heat tolerance classification. Results showed genotype-specific responses of varieties during heat stress and non-heat stress conditions. EL15 had the best agromorphic performance and appeared to be the best elite line. Identification of gene-specific SSR markers has proven to be effective in understanding heat tolerance for future marker-assisted selection.
M. ‘Teresita Lantin-Rosario’ and M. ‘Dolores A. Ramirez’ – New Varieties of Mussaenda
Gerlie P. Antesco, Jennelyn C. Bengoa, and Maria Luisa D. Guevarra
Received: July 22, 2022/ Revised: November 22, 2022/ Accepted: November 23, 2022
An outstanding selections of Mussaenda developed at the Institute of Plant Breeding (IPB), College of Agriculture and Food Science (CAFS), University of the Philippines Los Baños (UPLB) were registered to the National Seed Industry Council as new varieties. These are Mussaenda ‘Teresita Lantin-Rosario’ and Mussaenda ‘Dolores A. Ramirez’, named after an ornamental plant breeder and a National Scientist, respectively, in recognition of their significant contributions to the fields of genetics and plant breeding. Mussaenda ‘Teresita Lantin-Rosario’ is a hybrid and a progeny from a cross between M. ‘Maria Makiling’ and M. ‘Diwata’. The calyx lobes are all petaloid, numerous, and hairy. Petaloids are creamy white (157C) with visible midrib and pale yellow-green veins underneath, are ovate to suborbicular in shape, and are 5.0–9.3 x 3.7–7.5 cm in size. M. ‘Dolores A. Ramirez’ is also a hybrid from the cross M. ‘Maria Makiling x M. ‘Doña Trining’. The calyx lobes are all petaloid, two to three of which are more enlarged while the rest are partially expanded in a cluster, are elliptic-lanceolate to ovate-orbicular in shape, 4.5 ˗ 9.0 x 0.3 ˗ 6.2 cm in size, and are empire rose (48A) with prominent pinkish white veins above and orient pink (36D) below with a tinge of yellow-green (145A) towards the apex.
