In the coming decades, rice production needs to be carried out sustainably to keep the balance between profitability margins and essential resource input costs. Many fertilizers, such as N, depend primarily on fossil fuels, whereas P comes from rock phosphates. How long these reserves will last and sustain agriculture remains to be seen. Therefore, current agricultural food production under such conditions remains an enormous and colossal challenge. Researchers have been trying to identify nutrient use-efficient varieties over the past few decades with limited success. The concept of nutrient use efficiency is being revisited to understand the molecular genetic basis, while much of it is not entirely understood yet. However, significant achievements have recently been observed at the molecular level in nitrogen and phosphorus use efficiency. Breeding teams are trying to incorporate these valuable QTLs and genes into their rice breeding programs. In this review, we seek to identify the achievements and the progress made so far in the fields of genetics, molecular breeding and biotechnology, especially for nutrient use efficiency in rice.

The development of rice cultivars with nutrient use efficiency (NuUE) is highly crucial for sustaining global rice production in Asia and Africa. However, this requires a better understanding of the genetics of NuUE-related traits and their relationship to grain yield. In this study, simultaneous efforts were made to develop nutrient use efficient rice cultivars and to map quantitative trait loci (QTLs) governing NuUE-related traits in rice. A total of 230 BC₁F₅ introgression lines (ILs) were developed from a single early backcross population involving Weed Tolerant Rice 1, as the recipient parent, and Hao-an-nong, as the donor parent. The ILs were cultivated in field conditions with a different combination of fertilizer schedule under six nutrient conditions: minus nitrogen (–N), minus phosphorus (–P), (–NP), minus nitrogen phosphorus and potassium (–NPK), 75% of recommended nitrogen (75N), and NPK. Analysis of variance revealed that significant differences (p < 0.01) were noted among ILs and treatments for all traits. A high-density linkage map was constructed by using 704 high-quality single nucleotide polymorphism (SNP) markers. A total of 49 main-effect QTLs were identified on all chromosomes, except on chromosome 7, 11 and 12, which are showing 20.25% to 34.68% of phenotypic variation. With further analysis of these QTLs, we refined them to four top hotspot QTLs (QTL harbor-I to IV) located on chromosomes 3, 5, 9, and 11. However, we identified four novel putative QTLs for agronomic efficiency (AE) and 22 QTLs for partial factor productivity (PFP) under –P and 75N conditions. These interval regions of QTLs, several transporters and genes are located that were involved in nutrient uptake from soil to plant organs and tolerance to biotic and abiotic stresses. Further, the validation of these potential QTLs, genes may provide remarkable value for marker-aided selection and pyramiding of multiple QTLs, which would provide supporting evidence for the enhancement of grain yield and cloning of NuUE tolerance-responsive genes in rice.

Purpose: Sarangani, a province in Southern Philippines, is inhabited predominantly by tribal groups who depend on traditional rice farming for subsistence and livelihood. The purpose of this study is to identify current pressures to these upland communities and the interventions instituted to address them or mitigate their effects. Design/methodology/approach: This is an exploratory and cross-sectional research using the emic approach. Rapid rural appraisal techniques (i.e. focus group discussion, key informant interviews, community immersion and field observation) were concurrently undertaken in 15 farming villages in the Sarangani uplands. Findings: Results revealed that many upland families inhabited disaster-prone areas under conditions of hardship and abject poverty. Prevalent problems in these areas have largely arisen from the encroachment of modern agriculture, environmental degradation and changes in the socio-political and economic spheres. Consequently, food insecurity, cultural and genetic erosion and biodiversity losses have resulted in lowered Sarangani agro-ecosystem resilience. While policies and programs had been instituted to address these problems, positive results still remain to be realized. Social implications: Weak social networks in the Sarangani upland communities are attributable to their isolation and the disruptive influences of modernization. Agricultural modernization, in particular, caused the disintegration of community social structures and undermined overall well-being of the farmers. Sustainable strategies which harmonize modern and traditional systems of food production and environmental management are warranted to attain food security, environmental preservation and bio-cultural preservation. Originality/value: This study contributes to the present body of knowledge about threats to vulnerable agro-ecosystems inhabited mainly by indigenous tribes. And while only 15 farming villages were covered by the study, these results can serve as a microcosm of what is happening in traditional agro-ecosystems worldwide. The study is also expected to provide inputs to policymakers, which they can use in crafting policies to address problems in the Sarangani uplands.

The reliance on traditional or manual phenotyping creates significant operational bottlenecks in rice breeding due to its resource-intensive and time-consuming nature. This review focused on the significance of high-throughput phenotyping (HTP) as a promising technology that enables rapid, accurate, and non-destructive phenotyping of large populations. HTP has great potential to accelerate rice breeding by revolutionizing phenomics. This review examined the various applications of HTP in rice research, phenomics, and breeding. The use of HTP in rice has been substantiated through a range of cutting-edge technologies, such as drones, imaging systems, and sensor networks, that facilitate precise monitoring of key traits at various growth stages, assessment of responses to biotic and abiotic stresses, and the identification of genes or quantitative trait loci (QTLs) associated with essential characteristics. Also, this review discussed HTPs’ contributions to current rice breeding programs and documented notable challenges in scaling them. This review offers insights into optimizing HTP strategies to advance rice research, phenomics, and rice breeding.