Transgressive segregation it is the formation of extreme phenotypes, or transgressive phenotypes, observed in segregated hybrid populations compared to phenotypes observed in the parental lines. Transgressive segregation was observed only for seed length based on combined data. Tamcot 22 is a high yielding, average quality cultivar, tam b. Identification of new qtls and mapbased cloning of candidate genes are the. China 2 department of plant genetics, breeding and biotechnology, faculty of horticulture and landscape architecture, warsaw. Composite interval mapping for tic revealed four qtls. Variation and transgressive segregation in the backcross. A table containing the chromosome and the beginning and end positions in bp on the chromosome for each gene call will be returned along with a text file that you can download to your computer from the download results button. Transgressive segregation has also been observed for verticillium wilt resistance in an f 2 resistant pima s7. Dunbar, the cultivated soybean, showed the highest phenotypic values for shoot and root traits in comparison to the wild soybean, pi 326582a. From a survey of 171 studies that report phenotypic variation in segregating hybrid populations, we show that transgression is the rule rather than the exception. Moreover, transgressive segregation was observed in the progenies for palmitic, stearic, oleic, and linoleic acid table 1.
The appearance of these trangressive extreme phenotypes can be either positive or negative in terms of fitness. Soybean oil with elevated oleic acid is desirable because this monounsaturated fatty acid improves the nutrition and oxidative. The first genome duplication occurred within the last 60 million years and the latter between. Transcriptomic analysis of transgressive segregants. Transgressive segregation describes the occurrence of novel phenotypes in hybrids with extreme trait values not observed in either parental species. They are the worlds foremost provider of vegetable protein and oil. If both parents favorable alleles come together, it will result in a hybrid. Highdensitymarker qtl mapping can serve as an effective strategy to identify novel genomic information to facilitate crop improvement. Mapping quantitative trait loci for tolerance to pythium. A simple pedigree and then pedigree plus backcross system was used that allowed us to look at the f 3 and bc 1f 2 generations following the cross of tamcot 22tam b 18233 elsu, 06 we 624tamcot 22, and tamcot 2204 sid 842. Pdf transgressive segregation of isoflavone contents.
The miracle crop soybeans are often called the miracle crop. Soybean is an excellent source of vegetable protein and edible oil. Improved cotyledonary node method using an alternative explant derived from mature seed for efficient. Improvement of soybean meal through identification of high protein qtl in lines with exotic pedigree materials and methods plant materials. The causal agent of the disease is a soilborne oomycete pathogen pythium irregulare, the most prevalent and aggressive species of pythium in north central united states. Genetic diversity patterns in japanese soybean cultivars. Transgressive segregation indicates that the qtl from n0610035 and n0610011 parents are different than those from the g033385 and g033621 parents figure 1.
The total soybean area harvested has increased from 54. Reducing levels of palmitic acid should enhance the nutritive value of soybean oil for human consumption. Detection of quantitative trait loci for seed size traits. The adaptability of soybean to grow at relatively high latitudes is attributed to natural variations in major genes and quantitative trait loci qtls that control flowering time and maturity. In china, the cultivated soybean was domesticated from wild soybean more than 5,000 years ago and underwent two rounds of whole genome duplication. If both parents favorable alleles come together, it will result in a. In the present study, most of the root traits showed a transgressive segregation pattern. In the same way, the term regression works oppositely. However, tomato introgression lines developed between cultivated and wild tomatoes showed both transgressive and continuous patterns 31. Minsoy pi 27890 and noir 1 pi 2906 soybean cultivars were propagated in the growth chamber.
This phenomenon is known as transgressive segregation. A previously experimentally untested prediction is that the amount of transgression increases with the genetic distance between hybridizing species. Ninety six rils were planted in kyoto, osaka and nagano in 2003 and in osaka and nagano in 2004. Correlation among seed size traits correlation coefficients among seed size traits were calculated for each season table 2. Both usually produce fertile hybrids, and there is no marked obstacle to gene exchange, although the sterility due to abnormal chromosome pairing has often been observed. Transgressive segregation of isoflavone contents under the control of four qtls in a cross between distantly related soybean varieties article pdf available in breeding science 603. Transgressive segregation implies that both parents carry genes for the trait of interest, but those genes are located at different loci, and alleles for resistance from both parents can end up together in some of the progeny plants leading to a higher level of resistance than in the parents. Phenotypic novelty in experimental hybrids is predicted by. Burton abstract variants preserved in this way form the basis for modern japan is ahistorical center of genetic diversityfor soybean glycine cultivar improvement. In this study, we investigated how the diurnal expression pattern of the e1 gene is related to photoperiodic length. In genetics, transgressive segregation is the formation of extreme phenotypes, or transgressive phenotypes, observed in segregated hybrid populations compared to phenotypes observed in the parental lines. Changes in genome content generated via segregation of non. The superior fiber properties of gossypium barbadense l. Diurnal expression pattern, allelic variation, and.
It exhibits prevalent transgressive segregation such that the recombinant offspring of two inbred varieties can exhibit phenotypes outside of the parental range. Hybrid offspring generally possess traits or characteristics seen in ancestral species, which are. Transgressive segregation, adaptation and speciation. Among the major problems with soybeans are their beany flavor, flatusproducing ability, oxidative and flavor instability, deficiency of sulfurcontaining essential amino acids, presence of antinutritional factors, and proneness to attacks by such production hazards as diseases, insects, and weeds. The opportunity to increase soybean yields is at the fingertips of every soybean farmer in illinois. Agrobacteriummediated transformation of soybean and. Glycine max, soybeans, field crops, oleic acid, gene segregation, genotype, transgressive segregation, fatty acid composition, alleles, plant genetic resources, crossing abstract. Genetic variants in root architecturerelated genes in a. Quantitative trait loci analysis of seed oil content and. For evaluation of transcriptional profiles in these cultivars during seed development, immature green seed tissue from early to midmaturation stages bolon et al. Crop science abstract transgressive segregation for. Understanding the genetic basis of protein and oil content will improve the breeding programs for soybean. Transgressive segregation study in f 3 population of four groundnut crosses shreya1, ainmisha2 and r.
We examined transgressive phenotypes of flowering time in rice, and revealed transgressive segregation in f2 populations derived from a cross between parents with similar proximal days to heading dth. Additional file 1, suggesting that comprehensive genetic recombination of alleles had occurred between parents. One of the overarching goals of soybean breeding is to develop lines that combine increased yield with improved quality characteristics. Improving soybean production on your farm requires a systematic approach. The development of the first major soybeanprocessing industry in decatur, illinois, usa in the early 1920s gave soybean cultivation a great impetus hymowitz 1990, and today soybean is a leading crop in.
Agrobacterium soybean 1 updated 032210 agrobacteriummediated transformation of soybean and recovery of transgenic soybean plants. Transgressive segregation for very low and high levels of. Genetic properties responsible for the transgressive. Here, we assess the frequency of transgressive segregation in hybrid populations, describe its genetic basis and discuss the factors that best predict its occurrence.
In this report we document the existence of numerous non. The soybean, even though known as a miracle crop, is far from perfect. Transgressive segregation produces hybrid progeny phenotypes that exceed the parental phenotypes. A similar segregation pattern was reported for maximum root length and lateral root number in soybean 38. Pythium root rot is one of the significant diseases of soybean glycine max l. Linkage analysis and genomewide association study gwas tools were combined to detect quantitative trait loci qtl that are associated with protein and oil content in soybean. Although four maturity genes, e1 to e4, in soybean have been successfully cloned, their functional mechanisms and the regulatory network of photoperiodic flowering remain to be elucidated. Identification of novel qtl governing root architectural. Genetic diversity patterns in japanese soybean cultivars based on coefficient of parentage xingliang zhou, thomas e. The broadsense heritability h2oftheoilandfattyacids.
Transgressive segregation appears to be ubiquitous in plant hybrids. Permanent link to transgressive segregation for yield traits in f2 and f3 generation of soybean glycine max l. Transformation of soybean and use of transgenic lines in. It begins with understanding the needs of the soybean, the environment it prefers, adopting the best agronomic practices and stacking technology to optimize yield. Evaluation of genetic diversity of soybean introductions.
United states agriculture of the national sclerotinia. Frontiers quantitative trait locus mapping of flowering. Transgressive segregation study in f population of four. Transgressive segregation for oleate content in three. The presence of transgressive segregants in backcross generations have also been reported for different characters in tomato franklin, 1987, grain sorghum rao et al. All the changes we see are horizontal rather than vertical. Glycine soja, the annual wild progenitor of cultivated soybean, is widely distributed among east asian countries. Transgressive segregation for palmitic acid in seed oil of. Unlike heterosis, extreme phenotypes caused by transgressive segregation are heritably stable. Transgressive segregation an overview sciencedirect topics. Transgressive segregation in biomass yield of the f2 individuals may be explained by a wide range of allele combinations caused by the high ploidy level and the large number of different alleles. The plant genome original research eqtl networks reveal.
The alteration of fatty acid profiles in soybean glycine max l. Transgressive segregation for yield traits in f 2 and f 3 generation of soybean. Soybean was introduced into the united states in the early 1800s and was grown as a minor forage crop for many years wilcox 1987. The bushy, green soybean plant is a legume related to peas, groundnuts peanuts and alfalfa. Use this tool to retrieve the sequence coordinates for a list of soybean gene calls. However, few studies have been conducted in soybean for the identification of quantitative trait loci qtl for. Only three of 1 studies failed to report extreme phenotypes for at least one character, and of 579 traits examined. Transgressive segregation for tic was detected in all the environments tested. Genetic diversity and its use in soybean abe jun hokkaido university introduction cultivated and wild soybeans form a primary gene pool hymowitz, 2004.
When the water level in the ocean basins is at a lower level than their capacity, the sea starts to expose the previously covered lands. Soybean meal is a highly demanded product worldwide see table 4. All traits were highly correlated p and its opportunities soybeans. Both f 2 plants and f 3 families were identified that were either homozygous or heterozygous for loci controlling palmitic acid. The good news is that deforestation rates in the brazilian amazon dropped by 70 percent between 2005 and 2014. However the backcross inbred lines bils showed a transgressive segregation pattern for all traits reported with a higher range of phenotypic variation than either of the parental lines. Transgressive segregation of isoflavone contents under the. Transgressive segregation in breeding of crop plants more.
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