scholarly journals Quantifying the Yield Sensitivity of Modern Rice Varieties to Warming Temperatures: Evidence from the Philippines

2021 ◽  
Author(s):  
Ruixue Wang ◽  
Roderick M. Rejesus ◽  
Jesse B. Tack ◽  
Joseph V. Balagtas ◽  
Andy D. Nelson
Keyword(s):  
The Philippines ◽  
Rice Varieties ◽  
Yield Sensitivity

scholarly journals Reproductive, pathogenic and genotypic characterisation of five Meloidogyne graminicola populations from the Philippines on susceptible and resistant rice varieties

Nematology ◽  
2018 ◽  
Vol 20 (4) ◽  
pp. 299-318
Author(s):  
Ma. Teodora Nadong Cabasan ◽  
Arvind Kumar ◽  
Stéphane Bellafiore ◽  
Dirk De Waele
Keyword(s):  
Phenotypic Variability ◽  
The Philippines ◽  
Growth And Yield ◽  
Oryza Glaberrima ◽  
Rice Varieties ◽  
Single Nucleotide ◽  
Nematode Reproduction ◽  
Rdna Genes ◽  
Meloidogyne Graminicola ◽  
Disease Induction

Summary Five populations of Meloidogyne graminicola isolated from different rice-growing areas in the Philippines were characterised. The populations showed little phenotypic variability of second-stage juveniles and female perineal pattern. Differences in reproduction among M. graminicola populations were not observed on mature resistant Oryza glaberrima varieties ‘TOG5674’, ‘TOG5675’, ‘RAM131’ and ‘CG14’, or on susceptible O. sativa varieties ‘IR64’ and ‘UPLRi-5’. In all infected rice varieties, plant growth and yield-contributing traits showed no differences among the populations. A search on M. graminicola populations from the Philippines for single-nucleotide polymorphism on the sequences of Internal Transcribed Spacer (ITS) of rDNA genes and mtDNA indicated only few points of heteroplasmy. Nematode reproduction and disease induction of the five M. graminicola populations in the Philippines exerted the same level of aggressiveness and virulence. The absence of resistance-breaking populations of M. graminicola is important for the maintenance of durability of resistance to this important rice pathogen.

scholarly journals Breeding Temperate Japonica Rice Varieties Adaptable to Tropical Regions: Progress and Prospects

Agronomy ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 2253
Author(s):  
Myrish Pacleb ◽  
O-Young Jeong ◽  
Jeom-Sig Lee ◽  
Thelma Padolina ◽  
Rustum Braceros ◽  
...  
Keyword(s):  
The Philippines ◽  
Tropical Region ◽  
Japonica Rice ◽  
Rice Varieties ◽  
Temperate Japonica ◽  
Tropical Regions ◽  
Tropical Environments ◽  
Increasing Demand ◽  
Northeast Asian ◽  
The Tropics

Temperate japonica rice is mainly cultivated in temperate regions. Many temperate japonica varieties have a superior grain quality that is preferred in Northeast Asian countries such as Japan, Korea, and China. The changes in consumers’ preferences in Southeast Asia and Western countries has contributed to increasing the demand for temperate japonica. Most temperate japonica varieties developed in temperate regions typically exhibit extra-early flowering under the short-day conditions in the tropics, which usually results in severely reduced yields. Since 1992, we have been developing temperate japonica varieties that can adapt to tropical environments to meet the increasing demand for temperate japonica rice, having released six varieties in the Philippines. Especially, the yield of one of the temperate japonica varieties, Japonica 7, was comparable to the yields of leading indica varieties in the Philippines. Here, we discuss the current breeding initiatives and future plans for the development of tropical-region-bred temperate japonica rice.

scholarly journals The Green Revolution shaped the population structure of the rice pathogen Xanthomonas oryzae pv. oryzae

2019 ◽  
Vol 14 (2) ◽  
pp. 492-505 ◽  
Author(s):  
Ian Lorenzo Quibod ◽  
Genelou Atieza-Grande ◽  
Eula Gems Oreiro ◽  
Denice Palmos ◽  
Marian Hanna Nguyen ◽  
...  
Keyword(s):  
Population Structure ◽  
Plant Pathogens ◽  
Crop Improvement ◽  
Green Revolution ◽  
Agricultural Practices ◽  
The Philippines ◽  
Xanthomonas Oryzae ◽  
Rice Varieties ◽  
Evolutionary Trajectory ◽  
The Impact

Abstract The impact of modern agriculture on the evolutionary trajectory of plant pathogens is a central question for crop sustainability. The Green Revolution replaced traditional rice landraces with high-yielding varieties, creating a uniform selection pressure that allows measuring the effect of such intervention. In this study, we analyzed a unique historical pathogen record to assess the impact of a major resistance gene, Xa4, in the population structure of Xanthomonas oryzae pv. oryzae (Xoo) collected in the Philippines in a span of 40 years. After the deployment of Xa4 in the early 1960s, the emergence of virulent pathogen groups was associated with the increasing adoption of rice varieties carrying Xa4, which reached 80% of the total planted area. Whole genomes analysis of a representative sample suggested six major pathogen groups with distinctive signatures of selection in genes related to secretion system, cell-wall degradation, lipopolysaccharide production, and detoxification of host defense components. Association genetics also suggested that each population might evolve different mechanisms to adapt to Xa4. Interestingly, we found evidence of strong selective sweep affecting several populations in the mid-1980s, suggesting a major bottleneck that coincides with the peak of Xa4 deployment in the archipelago. Our study highlights how modern agricultural practices facilitate the adaptation of pathogens to overcome the effects of standard crop improvement efforts.

scholarly journals Molecular Detections and Resistance Response of Six Rice Varieties to Tungroviruses from South Sulawesi

2020 ◽  
Vol 24 (1) ◽  
pp. 89
Author(s):  
Saipul Abbas ◽  
Sri Sulandari ◽  
Sedyo Hartono ◽  
Y. Andi Trisyono
Keyword(s):  
Sequence Analysis ◽  
Plant Resistance ◽  
Molecular Detection ◽  
The Philippines ◽  
Rice Varieties ◽  
Resistance Response ◽  
South Sulawesi ◽  
Resistant Varieties ◽  
Moderately Resistant ◽  
Infected Sample

The suspected rice virus is found in the field, namely the tungrovirus which is transmitted by green leafhoppers (Nephotettix virescens). The study aimed to detect the tungrovirus molecularly and examine the resistance response of six rice varieties from the transmission of tungrovirus samples from South Sulawesi on a greenhouse scale. Based on the results of molecular detection with RTSV PCR of the double infected sample with DNA bands 1115 bp and RTBV of around 430 bp, Sidrap, and Maros samples were infected by 430 bp size RTBV, while Wajo sample was not detected by both viruses. The results of RTBV sequence analysis showed that the grouping of Sidrap was still one group with Maros and Pinrang samples and different from the group of samples from Malaysia, Thailand, and Philippines. While the grouping of RTSV shows that Pinrang samples are still one group with samples from Bali, Subang, and different from those of the Philippines, India, and Malaysia. The results of transmission in the greenhouse on six rice varieties (TN1, Ciherang, Mekongga, Tukad Unda, Inpari 36, Inpari 37) showed different plant resistance responses such as susceptible, moderately resistant, and resistant reactions based on the amount of disease intensity caused. Varieties that are classified as susceptible are TN1 and Ciherang varieties, moderately resistant, namely Mekongga and Tukad Unda varieties, and resistant varieties namely Inpari 36 and Inpari 37 varieties.

scholarly journals Productivity and Profitability of Aromatic Rice Production in the Philippines

2021 ◽  
Vol 8 (4) ◽  
pp. 209-221
Author(s):  
Jesusa C Beltran ◽  
Kristine Marie A Daplin ◽  
Rhemilyn Z Relado-Sevilla ◽  
Flordeliza H Bordey ◽  
Rowena G Manalili ◽  
...  
Keyword(s):  
Import Substitution ◽  
The Philippines ◽  
Rice Cultivation ◽  
Yield Enhancement ◽  
Aromatic Rice ◽  
Rice Varieties ◽  
Yield Level ◽  
Level Data ◽  
Baseline Information ◽  
Local Farmers

With the 2019 implementation of the Rice Tariffication Law (RTL), prices of ordinary white rice are expected to go down as a response to the influx of cheaper rice imports. This could put the local farmers at a disadvantage and could provoke them to reduce rice cultivation. Production of aromatic rice, a type of specialty rice with pandan-like scent induced by 2-acetyl-1-pyrroline (2AP) compound, could serve as a viable enterprise for the local farmers. Covering the provinces of Oriental Mindoro and Apayao, this study was conducted to produce baseline information and gain a comprehensive understanding of the production and potentials of aromatic rice. A survey was carried out to obtain 2017 cropping season farm-level data from 82 market-oriented farmer-respondents. Descriptive statistics and costs and returns structure were employed for data analysis. Results showed that venturing into aromatic rice cultivation can be a viable enterprise for the farmers as a coping mechanism with the ill effects of RTL. Yield level of modern aromatic rice varieties is at par with the national average. Aromatic rice cultivation also appeared to be profitable. Findings showed that the current local aromatic rice industry has high potential for expansion and opportunity for import substitution. Furthermore, top aromatic rice varieties in the country must be looked into to increase profitability. With these conclusions, strategies for yield enhancement, cost reduction, and premium quality preservation are recommended.

scholarly journals Dynamics of bacterial blight disease in resistant and susceptible rice varieties

2022 ◽  
Author(s):  
Jennifer T. Niones ◽  
Ryan T. Sharp ◽  
Dindo King M. Donayre ◽  
Eula Gems M. Oreiro ◽  
Alice E. Milne ◽  
...  
Keyword(s):  
Primary Infection ◽  
Bacterial Blight ◽  
Short Range ◽  
Disease Incidence ◽  
The Philippines ◽  
Resistant Variety ◽  
Rice Varieties ◽  
Infection Efficiency ◽  
Spatial Spread ◽  
Secondary Spread

AbstractBacterial blight (X. oryzae pv. oryzae) is a serious disease in rice across the world. To better control the disease, it is important to understand its epidemiology and how key aspects of this (e.g. infection efficiency, and spatial spread) change according to environment (e.g. local site conditions and season), management, and in particular, variety resistance. To explore this, we analysed data on the disease progress on resistant and susceptible varieties of rice grown at four sites in the Philippines across five seasons using a combination of mechanistic modelling and statistical analysis. Disease incidence was generally lower in the resistant variety. However, we found no evidence that the primary infection efficiency was lower in resistant varieties, suggesting that differences were largely due to reduced secondary spread. Despite secondary spread being attributed to splash dispersal which is exacerbated by wind and rain, the wetter sites of Pila and Victoria in south Luzon tended to have lower infection rates than the drier sites in central Luzon. Likewise, we found spread in the dry season can be substantial and should therefore not be ignored. In fact, we found site to be a greater determinant of the number of infection attempts suggesting that other environmental and management factors had greater effect on the disease than climate. Primary infection was characterised by spatially-random observations of disease incidence. As the season progressed, we observed an emerging short-range (1.6 m–4 m) spatial structure suggesting secondary spread was predominantly short-range, particularly where the resistant variety was grown.

scholarly journals Dynamic Insertion of Pot3 in AvrPib Prevailing in a Field Rice Blast Population in the Philippines Led to the High Virulence Frequency Against the Resistance Gene Pib in Rice

2019 ◽  
Vol 109 (5) ◽  
pp. 870-877 ◽  
Author(s):  
Toluwase Olukayode ◽  
Berlaine Quime ◽  
Yin-Chi Shen ◽  
Mary Jeannie Yanoria ◽  
Suobing Zhang ◽  
...  
Keyword(s):  
Resistance Gene ◽  
Rice Blast ◽  
Indica Rice ◽  
The Philippines ◽  
Avirulence Gene ◽  
Rice Varieties ◽  
Breeding Programs ◽  
Genome Wide ◽  
A Genome ◽  
Polymerase Chain

The Magnaporthe oryzae avirulence gene AvrPib is required for the resistance mediated by its cognate resistance gene Pib, which has been intensively used in indica rice breeding programs in many Asian countries. However, the sequence diversity of AvrPib among geographically distinct M. oryzae populations was recently shown to be increasing. Here, we selected a field population consisting of 248 rice blast isolates collected from a disease hotspot in Philippine for the analysis of AvrPib haplotypes and their pathogenicity against Pib. We found that all of the isolates were virulent to Pib and each of them contained an insertion of Pot3 transposon in AvrPib. Moreover, Pot3 insertion was detected in different genomic positions, resulting in three different AvrPib haplotypes, designated avrPib-H1 to H3. We further conducted a genome-wide Pot2 fingerprinting analysis by repetitive element palindromic polymerase chain reaction (PCR) and identified seven different lineages out of 47 representative isolates. The isolates belonging to the same lineage often had the same AvrPib haplotype. In contrast, the isolates having the same AvrPib haplotypes did not always belong to the same lineages. Both mating types MAT1-1 and MAT1-2 were identified in the population in Bohol and the latter appeared dominant. On the host side, we found that 32 of 52 released rice varieties in the Philippines contained Pib diagnosed by PCR gene-specific primers and DNA sequencing of gene amplicons, suggesting that it was widely incorporated in different rice varieties. Our study highlights the genetic dynamics of rice blast population at both the AvrPib locus and the genome-wide levels, providing insight into the mechanisms of the mutations in AvrPib leading to the breakdown of Pib-mediated resistance in rice.

Mining for Glyphosate-Resistant Genes in Rice Genotypes of the Philippines

2015 ◽  
Vol 16 (1) ◽  
Author(s):  
Alvin D. Palanog ◽  
Abie D. Rojo ◽  
Thea Mae Coleen B. Lanutan ◽  
Zayber B. Araya ◽  
Le-Ann G. Dogeno
Keyword(s):  
Survival Rate ◽  
Management Practices ◽  
Severity Index ◽  
The Philippines ◽  
Maturity Stage ◽  
Rice Varieties ◽  
Rice Plants ◽  
Lattice Design ◽  
Resistant Genes ◽  
Rice Genotypes

This study aimed to identify and characterize rice genotypes possibly possessing glyphosate-resistant genes, promoting the ability to withstand non-selective, systemic herbicides. The field establishment was based on alpha lattice design replicated into two with a plot size of 2 x 10 rows. All crop management practices followed the PalayCheck System®. At 14 DAT, the glyphosate-based herbicide (Round-up) was directly applied in rice plants. Survival and severity percentage were recorded from 4days to 20 days after herbicide application when the rice plants were observed reacting to the application while agronomic parameters were gathered at maturity stage. Out of one hundred rice genotypes, only 12 exhibited moderate to strong resistance to glyphosate-based herbicide while other genotypes stunted and wilted to death. The 12 genotypes are as follows: Kinastila, Binundor, Dinorado, Kalipao, Inanod, Camoros, Minondoc, Innano, Zambales, Maliket (Red), Kilay, and Simmaba. Among these twelve genotypes, Zambales is the most tolerant to glyphosate herbicide with highest survival rate and low severity index followed by Kalipao, Innaano and Kilay which have moderate survival rate and low severity rate. Identified resistant genotypes were agro-morphological characterized. Zambales genotype has the tallest plant height and highest spikelet number while the superior genotypes for the number of productive tillers, panicle length and spikelet fertility were Minondoc, Simmaba and Kinastila, respectively. These results show that the genotypes being tested have a wide variation in agro-morphological traits. Ultimately, 12 genotypes were identified as tolerant to glyphosate-based herbicide. Further evaluation and characterization are still required to verify the resistance of identified genotypes. These germplasms are promising materials for future breeding and research purposes in developing non-transgenic glyphosate-resistant rice varieties. Keywords-Genotypes, glyphosate resistance, morphological diversity, severity index, Philippines

Adoption and Spatial Diversity of Later Generation Modern Rice Varieties in the Philippines

2008 ◽  
Vol 100 (5) ◽  
pp. 1380-1389 ◽  
Author(s):  
C. C. Launio ◽  
G. O. Redondo ◽  
J. C. Beltran ◽  
Y. Morooka
Keyword(s):  
Spatial Diversity ◽  
The Philippines ◽  
Rice Varieties

Population sampling for planthoppers, leafhoppers (Hemiptera: Delphacidae & Cicadellidae) and their predators in flooded rice

1983 ◽  
Vol 73 (2) ◽  
pp. 345-355 ◽  
Author(s):  
T. J. Perfect ◽  
A. G. Cook ◽  
E. R. Ferrer
Keyword(s):  
Sampling Procedure ◽  
The Philippines ◽  
Population Estimates ◽  
Rice Varieties ◽  
Population Sampling ◽  
Flooded Rice ◽  
Suction Sampler ◽  
Sampling Procedures ◽  
Absolute Population

AbstractStudies on the precision levels and efficiencies of available insect suction samplers (D-Vac and FARMCOP) were undertaken in the Philippines to determine the best possible sampling procedure to derive absolute population estimates of delphacids, cicadellids and their predators in flooded rice. The D–Vac suction sampler when used in conjunction with an enclosure placed over the rice hill prior to sampling was found to be the most suitable. The sampling procedure adopted is described in detail, and sampling efficiencies for the D–Vac are given for nymphs and adults of the delphacids and cicadellids and their predators. These values could be used by other workers following the sampling procedures described here on modern rice varieties grown under flooded conditions to achieve absolute population estimates.

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