The conventional soybean breeding program by single seed descent method required around 8 to 9 years to develop a cultivar. Through the advancement of breeding techniques, such as marker-assisted selection, required resources could be significantly saved, but the generation advancement step still slows down the entire soybean breeding program time course. In this study, 28 soybean varieties were tested to find the optimal speed breeding conditions for soybeans that could rapidly advance one generation with 2 light sources, 3 light conditions, and 2 planting densities. Plants were kept under short-day conditions (9 hours light/15 hours dark). We optimized the growth conditions for shortening the period of soybean generation progression based on speed breeding. The optimizing conditions are as follows. (1) Irradiation using LED light source for 9 hours, (2) 506 mmol/(m2∙s) of PPFD at 30 cm from the ground, (3) Planting density of 5 cm × 5 cm, (4) temperature of 25℃ ± 2℃ and (5) humidity of 50% ± 10%. If this condition is used, soybeans can be advanced by one generation within an average of 73 days. It is possible to advance five generations a year using only indoor speed-breeding system. Furthermore, if it includes the development of lines in the field, four generation per year, which is advance three generations using indoor speed-breeding system and one generation in the field, is allowed to increase soybean breeding speed with minimum input.
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The
objective
of this study was to develop high-throughput SNP or SNP-based markers by re-sequencing of two peanut cultivars, ‘K-Ol’ and ‘Pungan’. The whole genome re-sequencing for the two cultivars was performed to produce sequences of 35.3 × 109 bp with 350 × 106 reads and 32.0 × 109 bp with 318 × 106 reads, respectively. As compared with the peanut reference genome, the distribution of homozygous and heterozygous SNPs on each chromosome showed very similar patterns between ‘K-Ol’ and ‘Pungan’, and most of them were in intergenic-region regardless of the peanut cultivars and reference genome type. The SNPs identified between the two peanut cultivars were evenly distributed across chromosomes of peanut diploid A and B reference genomes. It indicated that these SNPs could be available to construct a genetic map using the segregating population derived from a cross between ‘K-Ol’ and ‘Pungan’. Total 61 CAPS marker were developed and tested for their availability. Of the CAPS markers, 60 CAPS markers produced normal PCR products and 18 out of them presented polymorphism among 6 peanut varieties. Results of the present study could provide useful genetic resources to facilitate marker-assisted selection for breeding programs as well as germplasm screening for peanut.
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