No abstract

A quantitative trait locus (QTL) gw8.1 was detected in the population derived from a cross between the elite japonica cultivar, 'Hwaseong' and Oryza rufipogon (IRGC 105491). Near isogenic lines (NILs) harboring the O. rufipogon segment on chromosome 8 showed increased grain length and weight compared to those of the recurrent parent, Hwaseong. This QTL was mapped to a 175.3-kb region containing 28 genes, of which four were considered as candidates based on the presence of mutations in their coding regions and as per the RNA expression pattern during the inflorescence stage. Leaves and panicles obtained from plants harvested 5 days after heading showed differences in gene expression between Hwaseong and gw8.1-NILs. Most genes were upregulated in O. rufipogon and gw8.1-NIL than in Hwaseong. Scanning electron microscopy analysis of the lemma inner epidermal cells indicated that cell length was higher in gw8.1 NIL than in Hwaseong, indicating that gw8.1 might regulate cell elongation. Among the candidate genes, LOC_Os08g34380 encoding a putative receptor-like kinase and LOC_Os08g34550 encoding putative RING-H2 finger protein were considered as possible candidates based on their functional similarity.

No abstract

High-quality molecular markers are essential for marker-assisted selection to accelerate breeding progress. Compared with diploid species, recently diverged polyploid crop species tend to have highly similar homeologous subgenomes, which is expected to limit the development of broadly applicable locus-specific single-nucleotide polymorphism (SNP) assays. Furthermore, it is particularly challenging to make genome-wide marker sets for species that lack a reference genome. Here, we report the development of a genome-wide set of kompetitive allele specific PCR (KASP) markers for marker-assisted recurrent selection (MARS) in the tetraploid minor crop perilla. To find locus-specific SNP markers across the perilla genome, we used genotyping-by-sequencing (GBS) to construct linkage maps of two F2 populations. The two resulting high-resolution linkage maps comprised 2,326 and 2,454 SNP markers that spanned a total genetic distance of 2,133 cM across 16 linkage groups and 2,169 cM across 21 linkage groups, respectively. We then obtained a final genetic map consisting of 22 linkage groups with 1,123 common markers from the two genetic maps. We selected 96 genome-wide markers for MARS and confirmed the accuracy of markers in the two F2 populations using a high-throughput Fluidigm system. We confirmed that 91.8% of the SNP genotyping results from the Fluidigm assay were the same as the results obtained through GBS. These results provide a foundation for marker-assisted backcrossing and the development of new varieties of perilla.

This is an Open-Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.Plant Breed. Biotech. 2016 (February) 4(1):51~60 http://dx.ABSTRACT Grain size is one of the most important factors determining grain yield in rice breeding. In previous studies, we constructed high-density maps for two quantitative trait loci (QTL) for grain weight, tgw2 and gw9.1, using progeny derived from crosses between the japonica cultivar Hwaseong and Oryza grandiglumis, and Hwaseong and O. rufipogon (IRGC 105491), respectively. The wild alleles contributed an increase in grain weight at these two loci. We developed an F2 population (146 plants) by crossing two near isogenic lines (NILs) harboring tgw2 and gw9.1 to know how they interact in the near isogenic background. Simple sequence repeat markers tightly linked to two QTL were used to check the genotype of the F2 population. Based on the genotype at two loci, 146 F2 plants were classified into 9 groups with a combination of three genotypes at each two loci. Two gene interaction was not significant (P=0.99) in the F2. Homozygous plants with wild alleles at two loci showed significantly higher 1,000 grain weight than plants with a single QTL in the F2 and F3. These results indicate that two QTLs act additively in distinct or complementary pathways in controlling GW. Gene expression analysis was also performed to know the relationship of the gw9.1 QTL with three major grain size genes with Hwaseong and two NILs plants at the transcription level. The results from this study provide insight into grain size regulation in rice and are likely to be useful for marker aided selection for grain size.