Rice breeding was conducted for a long time during historical times and is an important job in Vietnam because rice is the major food for domestic consumption and export. In this review, we have provided a comprehensive insight into the importance of promising rice germplasm resources, breeding achievements, and breeding approaches as well as discussed challenges and perspectives of rice breeding in this country. With rice germplasm and wild rice relative resources with rich and various genetic diversity, their useful genes and traits have been exploited and integrated into commercial varieties as the final outputs of rice breeding programs. New achievements of the modern genetics era have been approached and effectively contributed to breeding activities in this country. Genome sequences, molecular breeding, and mutation are powerful tools and playing vital roles in developing new varieties with characteristics of interest that should be followed by the current market demands. In the last decades, there has been a plethora of newly generated varieties by Vietnamese scientists and rice breeders and approved by the state authorities. However, very few domestic mega varieties have prevailed over the imported varieties. Therefore, rice breeding in this country is faced with big challenges, including limitations of backgrounds, budgets, and even talents in basic research to compete with other rice-producing countries. The target goals and long-term approaches for rice breeding should be paid explicitly in priority to ensure national food security and the advantage and development of rice breeding in this country.

Salinity stress is one of the most severe constraints limiting rice production worldwide. Thus, the development of salt-tolerant rice promises to deal with increasing food demand due to climate change effects. This study investigated the salinity tolerance of mutant rice by evaluating phenotype and genotype, using forty-two simple sequence repeat (SSR) markers linked to the salinity tolerance Saltol quantitative trait locus (QTL) in ten cultivars and mutant lines. Results of phenotypic screening showed that the mutant line SKLo/BC15TB and cultivar BC15TB performed salt tolerance, while the mutant line Bao Thai/DT 84 and cultivar DT84DB were sensitive to salt stress. The markers RM 493, RM 562, RM 10748, RM 518, RM 237, and RM 20224 were the most polymorphic in salinity tolerance. Among them, RM 237, RM 10748, and RM 224 showed the highest polymorphism information (PIC = 0.58). This study reveals that the three markers are profitable for classification of salinity tolerance in both cultivar and mutant rice. The mutant line SKLo/BC15TB and cultivar BC15TB were found to be promising candidates for diversity analysis of salt-tolerant rice. Findings of this study are useful for developing new salinity-tolerant rice cultivars towards climate change.

Pinto peanut (Arachis pintoi Krapov. & W.C. Greg.) is an herbaceous perennial plant which belongs to the Leguminosae family. This plant is well known for its use as a cover crop, but little information is available on the allelopathic potential of this legume. Therefore, this study aimed to explore the allelopathic effects of A. pintoi under various screening conditions and to analyze its potential allelochemicals using gas chromatography–mass spectrometry (GC-MS). In laboratory bioassays, aqueous extracts of A. pintoi powder exerted the average inhibition of the growth of Echinochloa crus-galli (55.1%), Oryza sativa (77.1%), and Vigna radiata (60.1%), respectively, of which the root lengths of the tested plants were the most suppressed. In greenhouse experiments, E. crus-galli was inhibited by 63.4% at 200 g/m² of A. pintoi dried powder application. In field trials, A. pintoi also significantly reduced the growth of E. crus-galli and natural weeds. By incorporating a dose of 200 g/m², the average inhibition of E. crus-galli was 43.9%, the dry weight of natural paddy weeds was 43.1%, and rice yield was simultaneously increased by 35%. The growth inhibitions of weeds and tested plants were proportional to the doses of A. pintoi applied and varied with the tested plant species. Among three different solvent extracts (methanol, hexane, and ethyl acetate), the hexane extract exerted the highest suppression against the growth of E. crus-galli and L. sativa by IC₅₀ against root and shoot growth = 4.08 and 8.4 mg/mL and 1.7 and 1.54 mg/mL, respectively, followed by ethyl acetate extract, while the least effective was methanol extract. From those extracts, a total of 35 substances were detected by GC-MS analyses, including 14 newly identified constituents, such as phenolic acids, stearic acid, palmitic acid, fatty acids, pyranones, and benzofurans, which may be responsible for the herbicidal effects of A. pintoi. This study suggests that A. pintoi may be used as a source of bioherbicide to minimize the dependency on harmful synthetic herbicides and enhance rice yield.

The CONSTANS (CO) transcription factor plays a key role in regulating photoperiodic flowering by integrating environmental signals and activating downstream flowering genes. However, no comprehensive information on the CO transcription factor family has been reported in Amaranthus species. In this study, we performed a genome-wide identification, characterisation, and expression analysis of the CO gene family in six Amaranthus species, including A. hypochondriacus, A. palmeri, A. cruentus, A. hybridus, A. tuberculatus, and A. tricolor. A total of 12 to 13 CO genes were identified in each species, and their chromosomal positions, gene structures, and physicochemical properties were analysed. Phylogenetic analysis categorised these CO genes into three distinct groups, revealing evolutionary relationships with CO genes from Arabidopsis thaliana and sugar beet. Gene structure analysis showed considerable diversity in exon-intron organisation, indicating functional differentiation within the CO family. Additionally, transcriptome analysis using RNA-Seq data demonstrated tissue-specific and stress-induced expression patterns, particularly under drought and herbicide treatments. This study provides the first comprehensive insight into the CO transcription factor family in Amaranthus species, offering a foundation for future research on photoperiodic flowering regulation and stress-response mechanisms in these species.

Thaumatin-like proteins (TLPs), classified as pathogenesis-related protein 5 (PR-5), constitute an important component of plant defense systems. However, systematic information on the TLP family in sugar beet (Beta vulgaris) remains limited. In this study, a genome-wide investigation of TLP genes was conducted to clarify their genomic features, evolutionary relationships, and expression behavior under biotic stress. A total of 21 TLPs were identified in the sugar beet genome. These genes showed uneven chromosomal distribution and displayed marked variation in gene length, exon-intron organization, and protein physicochemical properties. Phylogenetic analysis of Arabidopsis PR-5 proteins classified the sugar beet members into multiple conserved groups, with consistent gene structure patterns within each group. Expression profiling under Sclerotinia sclerotiorum infection revealed that BvTLP09, BvTLP10, BvTLP12, BvTLP04, and BvTLP01 were strongly induced, whereas other PR-5 genes showed weak, unchanged, or reduced transcriptional responses. Reanalysis of RNA-seq data from beet cyst nematode infection further demonstrated distinct expression patterns between resistant and susceptible varieties at early and late infection stages, indicating dynamic and genotype-dependent regulation of PR-5 genes. This study expands current knowledge of the PR-5 gene family in sugar beet and provides a basis for future functional studies on their roles in pathogen-responsive pathways.