[Show abstract][Hide abstract] ABSTRACT: Previously we reported the identification of seven quantitative trait loci (QTLs) associated with the rice yield measuring five parameters including panicles per plant (PPP), spikelets per panicle (SPP), seed set percentage (SSP), 1000-grain weight (TGW) and yield in 2012. Here we report the analysis of QTLs using the same trait parameters data of the mapping population in 2013 for detecting highly conserved QTL markers. A total of 6 QTLs were identified from chromosomes 1, 7, 8, 10, 11, and 12, which were contrasted with our previous results (chromosomes 1, 2, 4, 5, 6, 8, and 11). In this comparison, three QTLs from chromosome 1, 8, and 11 were only found to be associated with the components of yield over two consecutive years indicating high sensitivity of QTL markers to the environment. Of those three QTLs, SPP-associated marker RM12285 was found to be dominantly expressed by real-time PCR (qPCR). In addition, compared to our previous report the numbers of mapping population and markers were significantly increased for higher resolution markers from 70 to 120, and from 143 to 217, respectively. We also found that the parameter SPP was dominantly correlated with the rice yield. Furthermore, the double haploid (DH) population facilitated to analyze the epistatic effects for yield and yield components in rice. Taken together, combining multiple mapping population data over years possibly enables narrowing down to the highly conserved QTL markers against diverse environmental fluctuation caused by such as drought and high temperature. Thus, these data would be critically exploited to improve for the crop breeding strategy.
[Show abstract][Hide abstract] ABSTRACT: Two genetic linkage maps, constructed by DH and RILs populations derived from the same parents, were carried out for the identification and comparison of QTLs controlling yield traits across different years in rice (Oryza sativa L.). A total of 194 SSR and STS markers were used in two maps, of which 114 markers were same. The distribution of Samgang allele was higher in RILs population than it in DH population. Comparing with DH population, RILs population has more lines with higher yield and wider phenotypic transgressive segression for yield traits. Although most of QTLs for the same trait were different in two populations across different years, 8 QTLs (including gwp11.1, spp5.1, spp10.1, spp11.2, ssr1.1, ssr11.1, tgw9.1 and tgw11.1) were detected over 2 yr. It is important to note that ppp10.1, spp10.1 and tgw9.1 were identified in two populations, while spp10.1 and tgw9.1 were simultaneity observed across different years. Epistatic effects were more important than additive effects for PPP, SPP, yield in DH population and TGW, yield in RILs population. Epistatic effects of DH and RILs populations were different on the same genetic background in the present study, which illuminated the QE interaction played an important role on epistatic effect. Identification and comparison of QTLs for yield traits in DH and RILs populations should provide various and more precise information. The QTLs identified in present study would be valuable in marker-assisted selection program for improving rice yield.
Journal of Integrative Agriculture. 02/2013; 12(2):198–208.
[Show abstract][Hide abstract] ABSTRACT: The importance of genetic stability and bio-safety in the environment has recently been recognized for many (genetically modified) GM plants. This study evaluated the GM safety of transgenic rice and its environmental variance. Data on agronomic characters and principal component were collected for vitamin A-enriched GM rice and four check cultivars in a large GM field trial during 2009-2011. The cultivation environment was a large GM field and a greenhouse. In this experiment, there was no significant difference between the agronomic characters of the GM rice and those of a donor plant, 'Nagdong'. In terms of grain characteristics, the appearance and physicochemical characteristics of the GM rice and those of the donor plant were similar. However, the grain of the GM rice developed a white core and a white belly when planted in the greenhouse. The type and distribution of dominant weed species were not different in the GM rice and the 'Nagdong'. In addition, gene flow was not detected in the dominant weed species based on PCR analysis.
[Show abstract][Hide abstract] ABSTRACT: This study was carried out to investigate the agronomic traits, comparison of weed characteristics and possibility of gene flow in 'vitamin A enforced GM rice' and the donor plant, 'Nagdong'. The GM rice was not significantly different agronomic traits compared to the donor plant, Nagdong. Weed population changes were investigated in the cultivation of the GM rice and the donor plant, Nagdong. Dominant weed species and their dry matter did not show the difference between GM rice and the donor plant, Nagdong in macro-GM crop field. Dominant weed species with the GM rice and the donor plant, Nagdong were Monochoria vaginalis, followed by Eleocharis kuroguwai, Echinochloa crus-galli and Lindernia procumbens. The detection of gene from the GM rice was done using PCR, gene flow can't be detected by weed species. Results of this study on the agronomic traits, weed characteristics and possibility of gene flow has elucidated that GM rice might not be different from the donor plant, Nagdong.
[Show abstract][Hide abstract] ABSTRACT: This study was carried out to facilitate the functional analysis of rice genes. Some 297 insertion plants (1.7%) of the entire lines with the endogenous retrotransposon Tos17 were produced. Phenotypes of these plants in the S 2 generation were observed in the field according to different leaf types. Rolling leaf mutants showed thinner sclerenchymatous cells, defective arrangement of vascular bundles, and well-formed bulliform cells as compared to the parental cultivar. Two new copies of Tos17 were detected in the rolling leaf type. In the new leaf type, the copy number and activation of Tos12, 15 did not appear as 'Ilpum'. Flanking sequence tag (FST) analysis of Tos17 in the rolling leaf mutant indicated that new copies of Tos17 were transposed on chromosomes 11 and 12. Annotated homologues of the tagging genes on chromosome 11 were arabinoxylan rabinofuranohydrolase isoenzyme AXAH-I and II. The tagging gene in chromosome 12 was highly correlated with 6 kinds of genes including a transcript regulated factor and a rough sheath 2-like protein. This rolling leaf and flanking sequence data will stimulate the functional analysis of rice genes.
American Journal of Plant Sciences 01/2011; 2:56-62.
[Show abstract][Hide abstract] ABSTRACT: Rice lipid content as one of important ingredients of functional food and industrial products has become an entirely new target
in the rice breeding programs worldwide. A genetic linkage map spanning 12 rice chromosomes with an average interval of 10.51
cM between markers was created using 172 DNA markers, which intended to elucidate genetic basis of lipid content in brown
rice by QTL detection. Eight QTLs related to lipid content with LOD from 2.52 to 7.86 were mapped on chromosome1, 2, 3, 5,
6, 7 and 9 using a doubled haploid (DH) population from a cross of ‘Samgang/Nagdong’ with field experiments for five years.
Two QTLs of qLC5.1 and qLC6.1 in the intervals 5014-5024 and 6011-RM19696 were repeatedly detected over four years at average LOD scores of 4.85 and 4.21,
respectively. Five of eight QTLs tend to increase the lipid content from ‘Samgang’ alleles. Epistatic and environmental effects
played important roles and explained 42.20% of phenotype variations. Three QTLs of qLC6.1, qLC7.1 and qLC9.1 collectively explained much than 27% of phenotype variations and increased 0.25% of lipid content and, showed much than 85%
of selection efficiency for the lines with high lipid contents in the F7 population from a cross of ‘Samgang/Nagdong’. Thus
it provides the sufficient possibility to realize QTLs pyramiding and to promote process of rice breeding.
KeywordsLipid content–QTLs–MAS–Brown rice
[Show abstract][Hide abstract] ABSTRACT: This study was carried out to develop new cultivars using the generation of transformed rice by PCR analysis with DNA marker in each generation . In the previous study, we successfully developed the transgenic rice plants over-expressing the Arabidopsis antiporter CAX 1 (accession no. U57411) gene. The calcium concentration in brown rice of transgenic plants was higher than that of donor plants, Iipum, and was selected 3 lines out of 25 lines at cultured GMO field. The major agronomic traits such as culm length, panicle length and panicle number of 3 lines at transgenic plants were similar to wild type. Also these lines appeared to have disease resistance to rice blast, cold resistance as compared with donor types. The grain shape was similar to donor plant, however, the 1000 grain weight of brown rice was different from transgenic plants. These finding would be used for basic data of new variety registration.
Korean Journal of Plant Resources. 01/2008; 21(5).
[Show abstract][Hide abstract] ABSTRACT: Previously, we made a chimeric Arabidopsis thaliana vacuolar transporter CAX2B [a variant of N-terminus truncated form of CAX2 (sCAX2) containing the "B" domain from CAX1] that has enhanced calcium (Ca(2+)) substrate specificity and lost the manganese (Mn(2+)) transport capability of sCAX2. Here, we demonstrate that potato (Solanum tuberosum L.) tubers expressing the CAX2B contain 50-65% more calcium (Ca(2+)) than wild-type tubers. Moreover, expression of CAX2B in potatoes did not show any significant increase of the four metals tested, particularly manganese (Mn(2+)). The CAX2B-expressing potatoes have normally undergone the tuber/plant/tuber cycle for three generations; the trait appeared stable through the successive generations and showed no deleterious alternations on plant growth and development. These results demonstrate the enhanced substrate specificity of CAX2B in potato. Therefore, CAX2B can be a valuable tool for Ca(2+) nutrient enrichment of potatoes with reduced accumulation of undesirable metals.
[Show abstract][Hide abstract] ABSTRACT: Seed shattering is an important factor causing loss of grain yield before and during rice harvest. In the present study, the
quantitative trait loci regarding shattering scale, breaking tensile strength (BTS) and abscission layer (AL), the parameters
evaluating seed shattering habit by hand gripping, a digital force gauge and observation on AL, respectively, were identified
by using an doubled haploid line (DHL) population from a cross between a loose-shattering type Tongil variety, ‘Samgang’, and a moderately difficult shattering japonica variety, ‘Nagdong’. Eight QTLs consisted in four QTLs for shattering scale, two QTLs for AL, each one QTL for pulling and
bending strength were detected on six chromosomes, respectively. Among them, Qss1 with flanking markers RM6696 and RM476 explained
31% of phenotype variation in shattering scale. Furthermore, two new QTLs controlling shattering habit, Qss5-2 and Qal5-1,
were located on chromosome 5 at the interval 5028–5037 and 5021-RM289. They explained 10% and 12% of phenotype variations,
respectively. A total of eleven digenic epistatic loci were identified for four parameters. The identification of QTLs affecting
seed shattering habits is favorable to thoroughly dissect the genetic mechanism of the shattering habit and to apply for marker-assisted
selection in rice breeding system of specific regions.
KeywordsRice-Shattering scale-Pulling and bending strength-Abscission layer-QTLs
[Show abstract][Hide abstract] ABSTRACT: Two genetic linkage maps based on doubled haploid (DH) and recombinant inbred lines (RILs) populations, derived from the same
indica-japonica cross ‘Samgang × Nagdong’, were constructed to analyze the quantitative trait loci (QTLs) affecting agronomic traits in rice.
The segregations of agronomic traits in RILs population showed larger variations than those in DH population. A total of 10
and 12 QTLs were identified on six chromosomes using DH population and seven chromosomes using RILs population, respectively.
Three stable QTLs including pl9.1, ph1.1, and gwp11.1 were detected through different years. The percentages of phenotypic variation explained by individual QTLs ranged from 8
to 18% in the DH population and 9 to 33% in the RILs population. Twenty-three epistatic QTLs were identified in the DH population,
while 21 epistatic QTLs were detected in the RILs population. Epistatic interactions played an important role in controlling
the agronomic traits genetically. Four significant main-effect QTLs were involved in the digenic interactions. Significant
interactions between QTLs and environments (QE) were identified in two populations. The QTLs affecting grain weight per panicle
(GWP) were more sensitive to the environmental changes. The comparison and QTLs analysis between two populations across different
years should help rice breeders to comprehend the genetic mechanisms of quantitative traits and improve breeding programs
in marker-assisted selection (MAS).
Key wordsagronomic traits–epistatic QTLs–QE interactions–QTLs