Although much effort has been made to find agronomically important loci in the soybean plant, extensive linkage disequilibrium and genome duplication have limited efficient genome-wide linkage analyses that can identify important regulatory genes. In this respect, recombination block-based analysis of cultivated plant genomes is a potential critical step for molecular breeding and target locus screening. We propose a new three-step method of detecting recombination blocks and comparative genomics of bred cultivars. It utilizes typical reshuffling features of their genomes, which have been generated by the recombination processes of breeding ancestral genomes. To begin with, mutations were detected by comparing genomes to a reference genome. Next, sequence blocks were examined for likenesses and difference with respect to the reference genome. The boundaries between the blocks were taken as recombination sites. All recombination sites found in the cultivar set were used to split the genomes, and the resulting sequence fragments were named as core recombination blocks (CRBs). Finally, the genomes were compared at the CRB level, instead of at the sequence level. In the genomes of the five Korean soybean cultivars used, the CRB-based comparative genomics method produced long and distinct CRBs that are as large as 22.9 Mb. We also demonstrated efficiency in detecting functionally useful target loci by using indel markers, each of which represents a CRB. We further showed that the CRB method is generally applicable to both monocot and dicot crops, by analyzing publicly available genomes of 31 soybeans and 23 rice accessions.
Resequencing data is actively used for searching QTL or analyzing genetic diversity in the crops. However, the complexity of genome, caused by genome duplication, limits the utility of genome-wide association studies and linkage analyses to identify genes that regulate agronomically valuable traits. Here, we propose a comparative genomics approach based on core or common variation-based recombination blocks (CRB) using single nucleotide variation (SNV) density information. We found that the soybean genomes are assembled with long and distinct CRBs as large as 10Mb. CRB-based comparative genomics enabled us to accurately identify recombination blocks at the whole-chromosome level. We identified the Ih locus that determines the yellow hilum color in soybeans using CRB-based mapping with representative indel markers. These results suggest that the CRB-based comparison method is a promising platform for molecular breeding and map-based cloning.
This study was carried out to gain the basic informations about botanical characteristics of plant type and properties related to table quality for developing the new colored waxy corn hybrid. Materials used were produced by our laboratory in 2007 and their major traits were evaluated fro two years(2008 to 2009) at Corn Breeding Farm of Coll. of Agri. & Life in CNU. Items surveyed were major agricultural characteristics including ear length and traits related to edible. Botanical characteristics as a plant type and ear pattern of the developed waxy corn hybrids showed large ranges among them; stem height of CNU08H-h39 among used hybrids was the highest as 235.7cm, while CNUH08-15 was the lowest. Ear height of Daehackchal Gold 1 was the highest as 83.7cm and that of CNU08H-15 was the lowest among used hybrids. Ear length of CNU08H-h121 among used hybrids was the longest as 23.1cm, while that of CNU08H-71 was the smallest as 12.7cm. Kernel sugar content of the used hybrids appeared to be 16.1 to 13.0Brix(%). Especially, CNU08H-15, CNU08H-35 and CNU08H-h39 hybrids were highly appeared as 15 above. Pericarp thickness of check hybrid, Yeonongchal, was thicker as 46.0㎛, while that of CNU08H-39 compared to other hybrids showed the thinnest as 23.0㎛. From this study, we could obtain several superior colored hybrids with thinner pericarp and high sugar contents like CNU 08-39 and CNU 08-h121 hybrids. Accordingly, these hybrids will be apply as new developed variety through confirmed trials.
‘Taegang’ is a new six-rowed covered barley cultivar developed by the National Institute of Crop Science (NICS), R.D.A. This cultivar is developed from a cross between ‘Suwon287’ and ‘Olbori’ in 1992. An F8 selection was made at NCES in 2000 and it was te