The soybean Kunitz trypsin inhibitor (KTI) protein is responsible for the inferior nutritional quality of unheated or incompletely heated soybean meal. Ti locus controls presence or absence of Kunitz trypsin inhibitor protein. Genetic recombination or tight linkage between Ti locus and Satt228 marker that has been identified to be tightly linked to the Ti locus was detected for marker assisted selection (MAS) using two F2 populations of titi genotype in this study. Two F2 populations were developed from the cross of A29 (KTI protein present, TiTi genotype, AA genotype in Satt228 marker) x Gaechuck#1 and Gaechuck#2
(KTI protein absent, titi genotype, BB genotype in Satt228 marker). Among 31 F2 plants derived from A29 x Gaechuck#1, twenty nine F2 plants show BB genotype that indicates no recombination between Satt228 marker and Ti locus. Only 2 F2 plants show AA genotype that indicates recombination between Satt228 marker and Ti locus. Twenty eight F2 plants derived from A29 x Gaechuck#2 show BB genotype that indicates no recombination between Satt228 marker and Ti locus. Expected genetic ratio between Satt228 marker and Ti locus was 3.6 cM in F2 population.
Goami 2 is now well known as its extinguishing endosperm characteristics - it is far from the wild type, Ilpum, a premium taste Korean japonica cultivar. The endosperm of Goami 2 is high in fat, protein, and indigestible carbohydrate contents. One of the most extraordinary endosperm characteristic of Goami 2 is high level of amylose content, even though the hulled rice (brown rice) is totally opaque. There have been many studies to address the unique physico-chemical properties and possible usages as a healthy and functional food ingredient, especially, the high-amylose rice had a positive effect on lowering the blood glucose response in obesity and type 2 diabetes. Genetic analysis by using 44 SSR markers, crude linkage map (3~5 anchor markers per chromosome) was then constructed based on the genotypes detected among 112 F2 progenies derived from Goami 2 / Milyang 23 showed that major chromosomal regions on Chromosome 2 responsible for the variation of amylose contents. M2-53 on Chromosome 2 explains the highest variation and this region has not been reported as a putative QTL for amylose contents yet. More closely markers for application to breeding program can be developed using MutMap or Re-sequence methods.
Heading date in rice is a complex trait that is governed by multiple genes and environmental factors, such as day-length, temperature, and soil conditions. The genetic studies using DNA markers have facilitated the genetic dissection of heading date and many quantitative trait loci (QTLs) for heading date have been identified using several mapping population. In a previous study, a new quantitative trait loci (QTLs) for heading date have been identified using several mapping population. In a previous study, a new for heading date was detected near SSR marker RM215 on chromosome 9 using an advanced backcross line, WH29001, developed by introgressing chromosomal segments from an accession of Oryzaminuta (2n=48, BBCC, Acc. No.101141)into the O. sativa subsp. japonica cv. Hwaseongbyeo. The O. minuta allele of QTL contributed to an increase in heading date. To clarify whether dth9 could be dissected genetically, a high-resolution linkage mapping of dth9 was performed using alarge F2 population derived form the cross between one F4 plant which was homozygous for O.minuta in the target region RM5661-RM215 on chromosome9 and Hwaseongbyeo. Days to heading in the F2 population showed continuous variation rang form 102 to 113 days. The dth9 QTL further narrowed down at the interval between the SSR marker RM1553 and RM215 which was approximately 403kb in length based on the physical map of the region. The QTL for heading date(dth9) had not been detected in previous QTL studies between Oryza cultivars, indicating the existence of potentially novel alleles from O. minuta.