Rice (Oryza sativa L.) is an important agricultural commodity in Indonesia. The combination of stability analysis on yields was considered accurate in selecting superior genotypes. The objectives of this study were as follows: identify the effects of genotypes, the environment, and their interactions (GEIs) on the yields of Fe-tolerant rice; select superior genotypes (stable and high yields) under diverse environment conditions in Indonesia; and determine the mega-environments (MEs) and representative environments for Fe-tolerant rice development. Fifteen genotypes of Fe-tolerant rice were used for this study. Field experiments were conducted at six experimental fields in Indonesia using a randomized block design with two replications. A combined analysis of variance (ANOVA) was used to determine the effect of genotypes, the environment, and their interactions on Fe-tolerant rice yields. Parametric, non-parametric, AMMI (additive main effects and multiplicative interaction), GGE biplot, and SI (sustainability index) measurements were used to determine the superior genotypes. GGE biplot was also used to determine MEs and representative environments. The measurement results showed that genotypes, the environment, and their interactions significantly affected rice yields with contributions of 13.30%, 35.78%, and 50.92%, respectively. One superior Fe-tolerant rice genotype (stable and high yield) was selected based on all measurements, namely G4 (B14316E-KA-4). In this experiment, two MEs were generated. Lampung was identified as a representative environment for the development of superior genotypes. The results of this study can be used as a consideration in the release and development of new superior varieties of Fe-tolerant rice in Indonesia.

Iron (Fe) toxicity is a significant abiotic stress in swamp land. The study aimed to identify the candidate loci related to Fe toxicity tolerance through Genome-Wide Association Study (GWAS) approach. The study used 288 rice accessions consisting of 192 breeding lines and 50 local landraces, and custom-designed 384 rice SNPs-chips. A field evaluation was conducted in inland swamp for two season periods (2014 and 2015). Phenotypic data and association mapping were analyzed using XLSTAT and TASSEL 3.0. The candidate loci were analyzed by functional gene detection of the significant SNPs aligned to the Rice Annotation Project and the Institute for Genomic Research databases. Three linkage disequilibrium (LD) blocks were detected in the Fe tolerant population around the significant SNPs. The first LD block was mapped in chromosome 1 (the AtIRT gene and qFETOX1; qFETOX1-3 QTLs loci) resembled partitioning of Fe-toxicity tolerant mechanism. The second LD blocks located in chromosome 2 (qFE-TOX-2-1 and qFETOX-2 QTLs loci) and chromosome 3 (qFETOX-3 QTL, OsNAS1 and OsNAS2 loci), probably contributed to Fe exclusion mechanism. The third LD blocks located in chromosome 4 (OsFRO2 and qFETOX-4 QTL loci) and chromosome 7 (OsIRT2 and NAS3 loci). The third LD block found on tolerant genotypes both on vegetative and generative stages. This condition indicated that these loci were presumed playing a role for Fe toxicity tolerance in rice. Result of the study are beneficial for determining the strategy on developing Fe-toxicity tolerant rice for specific swamp land type through breeding programs.

Aims: Iron (Fe) toxicity is a major nutrient stress that severely limits lowland rice yield worldwide. While tolerant rice varieties have been identified, their specific physiological factors underlying the tolerance remain unclear. This study aims to clarify the physiological mechanisms that contribute to field-based Fe stress tolerance. Methods: Field trials were conducted at Fe-stressed alongside control sites in Indonesia. Three contrasting lowland Indica rice genotypes were used: Ciherang (sensitive), IR42 (tolerant), and a breeding line KA-28 (tolerant) derived from a cross between Ciherang and IR42. A hydroponic study was conducted to investigate responses of photosynthesis and gene expression. Results: In the field experiment, Ciherang exhibited the most severe leaf bronzing, biomass reduction, and > 50% yield loss, whereas IR42 and KA-28 maintained > 60% of control yield with milder symptoms. Sensitive Ciherang and tolerant KA-28 had similar shoot Fe concentrations (> 700 ppm), indicating that tolerance was due to a tissue-based mechanism rather than the exclusion of excess Fe at the root. The hydroponic study confirmed the “tissue-based” tolerance mechanism of KA-28 under Fe toxicity, with less impact of unit Fe on leaf symptoms compared to Ciherang. Reductions in photosynthetic rates and changes in a Fe-responsive vacuolar Fe transporter gene, OsVIT2 , per unit increase in Fe concentrations were more pronounced in Ciherang than in KA-28. Conclusions: These findings collectively suggest that the physiological insensitivity to increased Fe levels is the basis for the tissue-tolerance mechanism observed in KA-28 in the field. This study provides valuable insights for breeding Fe-tolerant rice varieties.

Background: This overview explores the use of entomopathogenic nematodes (EPNs), fungi (EPFs), bacteria (EPBs), and viruses (EPVs) as biological control strategies against the red palm weevil (RPW) (Rhynchophorus ferrugineus), a significant pest of date palms in Saudi Arabia. Laboratory and field studies have evaluated the efficacy of these pathogens, which employ different infection mechanisms to manage RPW populations. The review aims to provide insights into the pathogenicity and application methods of these microbial agents, supporting the development of sustainable integrated pest management strategies for date palm cultivation. Results: The results indicate that entomopathogenic nematodes (EPNs), fungi (EPFs), bacteria (EPBs), and viruses (EPVs) are effective microbial agents for controlling the red palm weevil (RPW), a significant pest of date palms in Saudi Arabia. Laboratory and field studies have demonstrated their efficacy, utilizing different infection mechanisms to manage RPW populations at various life stages. However, limitations exist, including a lack of comprehensive research on certain microbial pathogens and the need for further studies to optimize application methods and environmental adaptability. These gaps highlight the importance of this review in synthesizing findings and providing a solid foundation for future research on sustainable integrated pest management strategies for RPW control. Conclusion: This overview underscores the potential of entomopathogenic microorganisms as effective biocontrol agents against the red palm weevil, emphasizing their role in sustainable pest management strategies. Continued research is essential to address existing gaps and optimize the application of these microbial agents in date palm cultivation.

Resistance Spectrum of Double Haploid Lines Derivedfrom IR64 and Wild Rice Species, Oryza rufipogonContained the Blast Resistance QTL (Pir). Dwinita W.Utami, A. Dinar Ambarwati, Aniversari Apriana, AtmitriSisharmini, Ida Hanarida, Didier Tharreau, and Santosa.This study was initiated to determine the spectrum resistanceof the candidate durable blast resistance variety containedthe QTL (quantitative trait locus), Pir1 and 2. This QTLwas mapped on chromosome 2 detected using the advancedbackcross population (BC5) from the wild rice speciesOryza rufipogon to IR64. Pir (1 and 2) also establishedon double haploid (DH) population derived from the selectedlines of BC2F3 population, progenies from the sameparents. The DH lines were developed to speed up the fixationprocess of the recessive alleles in the selected lines.Near isogenic lines with different blast resistance genes andcombination were used in this study comparing to the DHpopulation on their resistance spectrum using the knownavr gene isolates both on green house and field screening.The determination of the resistance spectrum will useful onthe prediction of durability of blast resistance gene in DHpopulation. The results of spectrum resistance test in greenhouse and field showed that Pir1and Pir2 segregated on 1 : 1proportion related with specific respond to blast avr genePH14 and CM28 resistance. Pir1 was identic to Pi33 or Pi25and Pir2 to Pitq5 on spectrum resistance.

Rice is one of the main carbohydrate sources and is a suitable target for biofortification with an inexpensive and sustainable treatment to reduce iron (Fe) def