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Landrace rice genotypes AG4 were evaluated inTri Ton, Tinh Bien, AnGiang Province with three replications in a field experiment during 2019 to 2020. The analysis revealed significant differences among the genotypes against all the characters studied. In general, phenotypic variance is higher than the corresponding genotypic variance for all the characters studied. AG4 rice is considered as the unique landrace varietal group because of its aroma and superior grain quality.To confirm the presence or absence of fragrance in AG 4,a set of 11 lines was phenotypedby using gas chromatographic separation to quantify 2AP content in milled rice samples. KOH tested and PCR method with two directives RM223 and FMU1-2 are recorded to select the lines with the best fragrance followed by line7, 10 ,14 and 20.The shape is determined by the length and width ratio.From shape evaluation, length and width ratio of AG4 are high. Level of chalkiness is. There are mostly low contents on AG4, when doing rice quality analysing. It is the evidence for the deliciousness on rice. Milling quality determines the final yield and fracture rate of milled rice. Recorded line 7 for high milling rate is over 50%. Protein content of rice varieties ranges from 6.9 to 8.6%. Lines 7 and 56 have the highest protein content (8.5-8.6%). Characters like number of panicles per plant, panicle weightg, number of grains per panicle, and grain yield recorded are high. Grain yield analysis revealed significant differences among lines. Selected AG4, lines number 7 can be used in breed selection program in the nearest future to provide the local need.

BackgroundOryza sativa L. contains two cultivated subspecies, indica and japonica, which are considered to be derived from wild rice relative, O. rufipogon. Although domestication cinario of O. sativa has been extensively studied, it is still inconclusive and contradictory. Moreover, it remains to be revealed why O. rufipogon had acquired wide range of genetic diversity to fit various habitat and life cycle of plant from annual to perennial.ResultsAlthough O. rufipogon distributes in southeast Asia from Indonesia to India, perennial wild rice strains were distributed in deep-water area of the Mekong Delta in Southern Vietnam. Some of wild rice strains collected in Dong Thap were heterologous in the length of intron 20 sequence of single-copy nuclear PolA1 gene, encoding for the largest subunit of RNA polymerase I. Thus, these wild rice strains were probably considered as interspecific hybrids, because the S-type (0.14 kb) intron 20 was found in O. rufipogon, O. glumaepatula, and O. barthii while L-type (1.5 kb) was shared by O. longistaminata and O. meridionalis. Therefore, we identified two wild rice strains that contained homologous L-type intron 20 of PolA1 gene in the CLRRI collection. These two strains, named as MD1 and MD2, had fertile spikelet with long anthers which were typical feature of African O. longistaminata. In addition, MD1 strain and O. longistaminata shared the same protein tag (Ptag) sequence, which was different to that of O. rufipogon and O. sativa. Interestingly, MD1 strain contained plastid DNA with a 69-bp deletion in ORF100 which was shared with indica and annual O. rufipogon, but not with japonica and perennial O. rufipogon. ConclusionWe have identified that MD strains found in the Mekong Delta were probably O. longistaminata-like cryptic species and contributed to enlarge genetic diversity of O. rufipogon, and is probably involved in the origin of O. rufipogon indica ancestor of as the maternal lineage.

Oryza rufipogon Griff. is a perennial species of wild rice widely distributed along the channels and rivers of the Mekong Delta, Vietnam. This study attempted to find centers of diversity among wild rice populations in this area and their inter‐relationships. The highest genetic diversity was found in the Dong Thap population and the lowest in the Can Tho population. Maternal diversity evaluated using chloroplast INDELs detected ten plastid types, five of which were novel relative to other Asian countries. The mitochondrial genome suggested two unique deletions. One 699‐bp deletion via short tandem repeats was accompanied by another deletion including orf153. All accessions carrying the mitochondrial type were found in a particular plastid type. This unique maternal lineage was confined to specific channels where it showed vigorous vegetative growth in comparison to upstream areas where various maternal lineages and maximum genetic diversity occurred. This area along the Mekong Delta is a center of not only nuclear but also maternal diversity.

Present study was performed to analysis both physical and chemical properties of rice germplasm and heritability for yield components in combinations. A total of 44 lines/varieties obtained from Cuu Long Rice Research Institute genebank, and 30 F1 generation combinations were evaluated. The results showed that the rice line IR79008-B-11-B-B-1 showed overall good physical characters (head rice, grain length, grain width, chalkiness). In terms of chemical characteristics, three varieties IR75499-73-1-B, OM6162, and OM4900 were found to have good amylose content, gel consistency, protein content, gelatinization temperature, and aroma. A very notable finding was that the cross between OM6162/SwarnaSub1 that low amylose content (20.2%), high gel consistency (78.2 mm), high protein content (8.1%), appropriate gelatinization temperature (scale 5), low chalkiness (level 0), high heritability (0.9) for grain yield trait/cluster, and (0.84) for the number of panicles/cluster. Moreover these characters consist of plant height, panicles lenght, number of panicles/cluster, number of filled grains/panicle, number of unfilled/panicle, and grain yield/ cluster showed moderate to high heritability of mean for combination OM6162/SwarnaSub1. The results suggest that the grain yield trait/cluster and the number of panicles/cluster are important yield contributing traits to rice breeders for selecting ideal combinations for higher yield and quality of next generations.

Soybean production in Vietnam has recently been threatened by the widespread dissemination of soybean rust (SBR) caused by the fungus Phakopsora pachyrhizi. Application of molecular breeding is considered as a feasible method to improve soybean rust resistance and minimize the adverse effects from overuse fungicides in this country. In this study, we have successfully applied molecular markers in a backcross breeding program to introgress the Rpp5 gene of SBR resistance into HL203, an elite Vietnamese soybean variety, from two donor lines of DT2000 and Stuart 99084B-28. The plants in BC4F1 generation had maximum contribution from the recurrent parents and retained SBR resistance gene.