Obreht Dragana, Faculty of Sciences, Department of Biology and ...

UDC 575: 633.11 Original scientific paper

MARKER ASSISTED SELECTION IN BMQ RELATED BREEDING PROGRAMS Dragana OBREHT 1, Borislav KOBILJSKI 2, Mihajla ĐAN 1 and Ljiljana VAPA 1 1

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Faculty of Sciences, Novi Sad, Serbia Institute of Field and Vegetable Crops, Novi Sad, Serbia

Obreht D., B. Kobiljski, M. Đana and Lj. Vapa (2008): Marker assisted selection in BQM related breeding programs. – Genetika, Vol. 40, No. 1, 39-49. Implementation of marker assisted selection (MAS) in bread making quality (BMQ) oriented breeding programs could allow genetic potential assessment of genotypes prior to their phenotypic evaluation. The mechanisms underlying some quality traits in wheat are now understood. This knowledge, coupled with the availability of the DNA sequences of the genes encoding gluten proteins and the wide application of the PCR, has enabled the design of diagnostic DNA markers for these quality traits. Bread wheat breeding programs developed in Institute of Field and Vegetable Crops, Novi Sad have originated a wide range of quality cultivars with strong flours and hard grain texture. During twenty years, in the process of bread-making quality prediction, composition of HMW glutenin subunits were analysed beside standard technological parameters. However, in order to improve our breeding strategies new generations of PCR-based BMQ related markers were included in selection programs. This paper provides an overview of diagnostic DNA ______________________________

Corresponding author: Obreht Dragana, Faculty of Sciences, Department of Biology and Ecology,Trg D. Obradovica 2., 210000 Novi Sad,Phone: 021 485 2656,E-mail: [email protected]

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markers that are currently in use in foreign and domestic wheat selection programs. Key word: wheat, quality, MAS INTRODUCTION Wheat is one of the major food crops utilised worldwide. Modern cultivars of bread wheat (Triticum aestivum L.) and durum wheat (Triticum turgidum var. durum) are the result of extensive selection by breeders to meet the agronomic and quality requirements. The processing and end-use characteristics of the grain are under genetic and environmental control. For bread wheat, BMQ tests typically measure flour yield, protein concentration and composition, kernel texture, and dough mixing properties, and may also measure properties of baked goods such as loaf volume and crumb structure (BEASLEY et al., 2002). Gluten is a polymeric protein network and a main source of the viscoelastic properties in dough (BELDEROK, 2000). The major gluten fractions are glutenin proteins composed of high molecular weight glutenin subunits (HMW GS) and low molecular weight glutenin subunits (LMW GS). These subunits provide a structural backbone to the gluten macropolymer through formation of disulfide bonds (LINDSAY et al., 2000). Endosperm texture, that is whether the kernel is “hard” or “soft”, is the primary means of classifying wheat for commercial usage. The main effect of hardness on bread making qualities is attributed to higher starch damage during milling. This damage increases both water absorption and hydrolysis of starch into fermentable sugars that contribute to loaf volume (BELDEROK, 2000). Soft wheat kernels fracture more easily and produce finer-textured flours with less starch damage. Hard wheat produce coarser textured flours with higher levels of starch damage. Hard wheat is better suited for bread making, while soft wheat are preferred for cookies, cakes and pastries. In the past, selection of breeding lines with enhanced performance has relied on the direct measurement of the traits of interest. The scoring of most traits, however, requires laboratory testing or bioassay. In such cases, the availability of markers, that represent an indirect indicator of the trait of interest and that can be scored with relative ease, are of significant value to wheat breeders. Markers may be linked (i.e. have a probability of being co-inherited with the trait of interest) or diagnostic (also known as perfect) if the marker is directly associated with the gene that influences the trait. There are several types of markers used by plant breeders. A small number of morphological characteristics are linked to specific traits. Biochemical markers have found wide application in wheat breeding with the earlier observations that wheat endosperm storage proteins (prolamins), that may be prepared using a simple alcohol extraction, are extremely polymorphic between wheat lines (PAYNE, 1987). A small number of diagnostic antibody markers linked to wheat quality are available and these offer the advantage of being applicable in a simple, high throughput format such as the enzyme-linked immunosorbent assay (ELISA). A DNA marker may be defined as an assay for the detection of

D.OBREHT et al.: MAS IN WHEAT BMQ BREEDING

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polymorphism in DNA sequence between samples. A number of different DNA marker systems have been described most of which now rely on the sensitivity and specificity of the polymerase chain reaction (PCR). DNA markers offer the advantages of being applicable to any developmental stage and any tissue of the plant, and of producing results that are independent of environmental conditions. The main aim of presented paper is an overview of diagnostic DNA markers that are currently in use in foreign and domestic wheat BMQ oriented selection programs. Marker assisted selection for BMQ improvement based on composition of wheat endosperm proteins – biochemical and molecular diagnostic markers Electrophoretic analyses of seed storage proteins – HMW GS and LMW GS have proven to be very useful in evaluation and characterization of wheat quality. It was shown that up to 60-65% of variability in bread making quality can be accounted for by differences in HMW glutenin composition (PAYNE, 1987). HMW GS are encoded by homologous Glu-1 loci located on long arms of group 1 chromosomes in cultivated bread and durum wheats. High dough strength is used as a predictor of good quality bread wheat and it has been attributed largely to the type of allele present at the Glu-D1 locus, where the Glu-D1d allele (HMW GS 5+10) is most favourable. Contribution of Glu-A1 coded HMW GS to BMQ variation was minor and always was observed in synergic effect with Glu-D1 coded subunit 5+10 (GRAYBOSH et al., 1994; DENCIC and VAPA, 1996). Recently, it has been observed that Glu-B1 alleles also could enhance dough strength and BMQ (BUTOW et al., 2003). In Novi Sad wheat breeding program relationship between different Glu-1 loci or different Glu-1 allelic composition and quality parameters has been widely investigated (VAPA et al., 1995; OBREHT et al., 2002; VAPA et al., 2004) and obtained results have been incorporated in selection programs. Sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDSPAGE) is an efficient method for profiling HMW GS in wheat (Fig. 1), but in some cases difficulties arises when different subunits of the same mobility cannot be discriminated on the gel (BUTOW et al., 2003). In the case of alleles of the GluB1-encoded subunit Bx7 only small and unclear differences in electrophoretic mobility exists between subunit Bx7 and Bx7*. To overcome this problem a PCR marker, originally designed to discriminate Glu-1 Bx7 and Glu-1 Bx17 (MA et al., 2003), was used to differentiate two allelic variants of Bx7 HMW GS, i.e. Bx7* and Bx7oe (Fig. 2). Importance of this findings was confirmed by strong association between lines with an over expression of Bx7oe and high dough strength (BUTOW et al., 2003, DAVIDOVIC et al., 2004).

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Figure 1. SDS-PAGE electrophoregram of HMW GS

Figure 2. PCR assay for detection of two allelic variants of Bx7 HMW GS

The low molecular weight glutenin subunits (LMW GS) are encoded by loci consisting of multiple tightly linked genes, designated Glu-A3, -B3 and -D3 located on the short arms of group 1 chromosomes (SINGH and SHEPHERD, 1988). Whereas the HMW GS appear to contribute mainly to dough strength, the LMW GS are thought to play a major role in determining extensibility and to a lesser degree strength, both directly and via their interaction with the HMW GS (GUPTA et al., 1995; LUO et al., 2001). Based on analysis of extracts from the polymeric fraction of wheat gluten by SDS-PAGE, the LMW GS were divided into B-, Cand D-types, although it is now clear that only the B-type subunits represent true LMW GS. LMW GS alleles may be scored using SDS-PAGE (SINGH and SHEPHERD, 1988), although this is not straight forward due to the complexity of the banding patterns observed and the overlap of mobilities of the LMW GS and the gliadins. For these reasons, the study of the functionality of the LMW GS and the effect of allelic has received far less attention than that of the HMW GS. ZHANG et al. (2004) sequenced i-type LMW GS genes from cultivars containing each of seven different Glu- A3 alleles and developed a dominant marker set for identification of each allele Glu-A3a-g. Similar marker sets are not currently available for the identification of alleles of Glu-B3 and Glu-D3, although ZHANG et al. (2004) reported the development and application of gamma-gliadin markers that could be used to trace linked Glu-A3, -B3 and -D3 LMW GS alleles.


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Diagnostic DNA markers for detection of 1BL/1RS wheat-rye translocation The introduction of rye translocations into wheat lines has been used to introgress various yield and disease attributes. Translocations involving the short arm of chromosome 1 of rye, 1RS, significantly influence wheat variety performance, because 1RS carries resistance genes to disease-causing organisms and insects. Depending on the wheat genotype into which it is introduced, 1RS may also directly increase yield or serve as a selectable marker for higher-yield genes on translocations. Conversely, depending on the wheat genotype, 1RS chromatin can negatively impact wheat end-product quality and efforts to breed for quality (GRAYBOSH, 2001). For example, lines and varieties with 1RS sometimes have reduced flour yield or flour which produces undesirable ‘sticky dough’. Selection for or against the presence of rye chromatin may be accomplished using different marker systems to detect the presence of rye repetitive DNA sequences (JAVORNIK et al., 1991). A co-dominant DNA marker was developed for the specific detection of the common 1BL/1RS wheat-rye translocation using multiplexed PCR amplification of a chromosome 1B encoded LMW-glutenin gene and a chromosome 1R encoded u-secalin gene (de FROIDMONT, 1998). In addition, dominant DNA marker specific for Gli-B1 gamma-gliadin pseudogene (Fig. 3) was developed by DEVOS et al. (1995) and was useful for detecting the presence of the 1B/1R wheat-rye translocation in Novi Sad wheat breeding program (OBREHT, 2005).

Figure 3. Agarose gel electrophoresis of dominant marker specific for Gli-B1 gammagliadin pseudogene. N stands for “null” allele and points to the presence of 1BL/1RS translocation

Marker systems for endosperm texture detection Wheat hardness is mainly controlled by the Ha locus on the 5DS and is inherited as a single factor. Measurements of hardness indicative of end-use properties are generally made by near-infrared reflectance (NIR) spectrometry or particle size in milling fractions. Puroindoline a and b proteins, coded by Pina-D1 and Pinb-D1 loci, represent the molecular basis for grain hardness (GAUTIER et al., 1994). The presence or absence of the Pina-D1 gene, which is highly conserved in sequence between cultivars may be determined using gene-specific PCR and serves

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as a simple assay for discriminating Pina-D1 alleles a and b (GAUTIER et al., 1994). The SNPs underlying the Pinb-D1a and b alleles have been scored using allele-specific PCR (GIROUX and MORRIS, 1997), and the Pinb-D1c allele by cleavage of the amplified Pinb gene with PvuII (LILLEMO and MORRIS, 2000), and any single nucleotide polymorphism (SNP) scoring system would be suitable for the discrimination of any of the Pinb alleles. All hard wheat cultivars could be explained by mutations in either puroindoline a or b. Only one mutation at the Pina-D1 was found, while in hexaploid wheat cultivars eight different point mutations were reported at the PinbD1 (GIROUX and MORRIS, 1997; LILLEMO and MORRIS, 2000). Since the endosperm texture is the primary means of classifying wheat for commercial usage, knowledge of Pin loci diversity in breeding germ plasm is very important. Relationship between different allelic composition at Pin-D1 loci and quality parameters has been widely investigated. Survey of the allelic variability at Pin-D1 loci in 96 Serbian hexaploid cultivars revealed presence of two alleles at each of the analysed loci (Fig. 4). According to puroindoline profiles analysed cultivars could be divided in three groups: hard, semi-hard and soft (OBREHT et al. 2004).

Figure 4. Agarose gel electrophoresis of PCR amplified puroindoline a and b obtained by: a) Pina-D1 gene specific primers, b) Pinb-D1 SNP Gly-46 specific reverse primer c) Pinb-D1 SNP Ser-46 specific reverse primer

Application of genomic microsatellites as marker system in wheat BMQ breeding Bread wheat quality traits such as protein content, composition and strength are generally controlled by groups of multiple genes and these regions of the genome are called quantitative trait loci (QTL). These traits are often influenced by environmental factors and exhibit high genotype–environment interaction. The genetic basis for most of these traits is not well elucidated. It is clear that other non-gluten factors such as amylase activity, grain hardness (HOGG et al., 2005) and other minor prolamine-like proteins may account for a substantial unexplained variation in BMQ parameters. Currently, the most common method for QTLs mapping involves generating populations derived from single crosses and estimating recombination frequencies between marker loci and the genes of


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interest. Despite the widespread use of such QTL analysis approach, marker application is being impeded through the lack of information on the polymorphism and marker trait associations in genetic material relevant to most breeding programs worldwide. After QTLs detection phase, the next step towards genetic profiling of complex traits is assessment of the allelic variation at candidate region loci. Marker-trait association studies are considered as a feasible strategy for the molecular basis elucidation of complex traits in wheat breeding (KOBILJSKI et al., 2005; BRESEGHELLO and SORRELLS, 2006). Microsatellite markers, also termed simple sequence repeats (SSRs), which are chromosome-specific and evenly distributed along chromosomes (RODER et al., 1998), are ideally suited for tagging complex traits, for markerassisted selection (RODER et al., 2002; OBREHT et al., 2005) and to assess genetic diversity in wheat (KOBILJSKI et al., 2002; TANURDZIC et al., 2004). A large number of wheat microsatellite markers currently available make it feasible to detect and map QTLs in a wheat population, even from a cross between two wheat cultivars. Several studies have found evidence of the importance of chromosome 3A in wheat. QTLs were detected for quality related traits (GROSS et al., 2002) and for yield related traits (CAMPBELL et al., 2003). LAW et al. (2005) reported two highly significant QTLs for the BMQ parameters, namely loaf volume and Hagberg falling number (HFN). It was proposed that a single gene Lvl 1, located on the 3AL chromosome, was responsible for variation in baking quality performance. The second detected QTL, also located on 3A chromosome, could be a single gene controlling HFN. Following this idea, OBREHT et al. (2006) have exploited the potential uses of microsatellite markers in bread-making quality evaluation in a sample of 69 wheat genotypes that were genotyped with 3 microsatellites. Specific SSR alleles were tested for association with bread-making related parameters. The association study approach, which implies statistical analysis of marker and phenotypic data, showed significant association of specific allele at the GWM674 locus with Hagberg falling number in wheat. CONCLUSION All known types of markers for the prediction of wheat quality are a useful addition to the range of tools available to wheat breeding programs. In selecting the most appropriate molecular marker various factors must be considered including: the ease of use, the cost in time and resources, the type of data produced, the statistical tools available for analysis of the data, the ability to make valid comparisons among existing studies and the existence of a suitable context in which the results can be meaningfully interpreted. Marker technology has progressed to the point where the major practical limitation to implementation in plant breeding is the handling of large populations enough to identify target recombinants at the many loci we can now screen. Irrespective of improvements in marker technology, critical minimum population sizes are necessary to ensure with

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a high degree of certainty that a target genotype is present in a breeding population. Diagnostic DNA markers are very useful, especially for early generation screening of wheat lines. The availability of even a comprehensive range of such markers will, however, not replace the use of traditional wheat quality testing procedures for later generation screening and cultivar evaluation due to the highly complex (multigenic) nature of quality traits and the requirement to determine the influence of environment on final performance of wheat lines. Received January 18h, 2008 Accepted March 04th, 2008

REFERENCES BEASLEY, H.L., S. UTAYAKUMARAN, F.L.S TODDARD, S.J. PARTRIDGE, L. DAQIQ, P. CHONG

and F. BEKES (2002): Synergistic and additive effects of three high molecular weight glutenin subunit loci. II. Effects on wheat dough functionality and end-use quality. Cereal Chem. 79:301-307. BELDEROK, B. (2000): Developments in bread-making processes. 4. Survey of gluten proteins and wheat starches. Plant Foods for Human Nutrition 55: 30-39. BRESEGHELLO, F. and M.E. SORRELLS (2006): Association analysis as a strategy for improvement quantitative traits in plants. Crop Sci. 46: 1323 – 1330. BUTOW, B.J., W.MA, K.R.GALE, G.B. CORNISH, L.RAMPLING, O.LARROQUE, M.K. MORELL and F.BEKES (2003): Molecular discrimination of Bx7 alleles demonstrates that a highly expressed highmolecular-weight glutenin allele has a major impact on wheat flour dough strength. Theor. Appl. Genet. 107: 1524-1532. CAMPBELL, B.T., P.S.BAENZIGER, K.S.GILL, K.M.ESKRIDGE, H.BUDAK, M.ERAYMAN, I.DWEIKAT AND Y.YEN (2003): Identification of QTLs and environmental interactions associated with agronomic traits on chromosome 3A of wheat. Crop Sci. 43: 1493-1505. DAVIDOVIC, M., D .OBREHT, B.KOBILJSKI, and LJ. VAPA (2004): Marker assisted selection of Glu-B1 HMW glutenins in wheat. Proceedings of XXXIV Annual Meeting of ESNA (European Society for New Methods in Agricultural Research, Novi Sad, Serbia and Montenegro: 235 – 238. DEBUSTOS, A., P.RUBIO, C.SOLER, P.GARCIA and N.JOUVE (2001): Marker assisted selection to improve HMW-glutenin in wheat. Euphytica 119: 69-73. DEFROIDMONT, D. (1998): A co-dominant marker for the 1BL/1RS wheat-rye translocation via multiplex PCR. J. Cereal Sci. 27: 229-232. DENČIĆ, S. and LJ.VAPA (1996): Effect of intra and inter-allelic variation in Glu-A1 and Glu-D1 loci on bread-making quality in wheat. Cereal Res.Commun. 24: 317-322. DEVOS, K. M., G. J BRYAN., A. J.COLLINS, P.STEPHENSON

and DM..GALE (1995): Application of two microsatellite sequences in wheat storage proteins as molecular markers. Theor. Appl. Genet. 90: 247-252. GAUTIER, M.F., M.E.ALEMAN, A.GUIRAO, D. MARION and P.JOUDRIER (1994): Triticum aestivum puroindolines, two basic cysteine-rich seed proteins: cDNA sequence and developmental gene expression. Plant Mol. Biol. 25: 43-57.


47

GIROUX, M.J.

and C.F. MORRIS (1998): Grain wheat hardness results from highly conserved mutations in the friabilin components puroindoline a and b. Proc. Natl. Acad. Sci. 95: 6262-6266. GRAYBOSCH, R.A. (2001): Uneasy unions: Quality effect of rye chromatin transfers to wheat. J. Cereal Sci. 33: 3-16. GRAYBOSCH, R.A., PETERSON C.J., LEE J.H. and SHELTON D.R. (1994): Effect of glutenin protein polymorphism on breadmaking quality of winter wheats. Crop Sci. 34: 628-635. GROSS, C., G.GAY, M.R. PERRETANT, L.GERVAIS, M.BERNARD, F. DEDRYVER

and G.CHARMET (2002): Study of the relationship between pre-harvest sprouting and grain colour by quantitative trait loci analysis in white x red grain bread-wheat cross. Theor. Appl. Genet. 104: 39-47. GUPTA, R.B., S.Y. POPINEAU, J. LEFEBVRE, M.CORNEC, G.J. LAWRENCE and F.MACRITCHIE (1995): Biochemical basis of flour properties in bread wheats. II. Changes in polymeric protein formation and dough/gluten properties associated with the loss of low Mr or high Mr glutenin subunits. J. Cereal Sci. 21: 103-116. HOGG, A.C., B.BEECHER, J.M. MATRIN, F. MEYER, L.TALBERT, S.LANNING and M.J. GIROUX (2005): Hard wheat milling and bread baking traits affected by the seed-specific overexpression of puroindolines. Crop Sci. 45: 871-878. JAVORNIK, B., T.SINKOVIĆ, LJ.VAPA, R.M., D.KOEBNER and W.J. ROGERS (1991): A comparison of methods for identifying and surveying the presence of 1BL.1RS translocations in bread wheat. Euphytica 54 : 45-53. KOBILJSKI, B., S.QUARRIE, S.DENČIĆ, J KIRBY and M.IVEGES (2002): Genetic diversity of the Novi Sad wheat core collection revealed by microsatellites. Cell. & Mol. Bio. Lett. 7: 685-694. KOBILJSKI, B., S.DENČIĆ, N.HRISTOV, N. MLADENOV, S.QUARRIE, P.STEPHENSON and J.KIRBY (2005): The potential of microsatellites for marker-assisted breeding for improved grain yield in wheat. Proc. 7th Inter. Wheat Conf., Mar Del Plata, Argentina. pp.100. LAW, C.N., D.G. BHANDARI, S.E. SALMON, P.W. GREENWELL, I.M.FOOT, S.P. CAUVAIN, E.J. SAYERS and A.J. WORLAND (2005) :Novel genes on chromosome 3A influencing bread-making quality in wheat, including a new gene for loaf volume, Lvl 1. J. Cereal Sci. 41: 317-326. LILLEMO, M. and C. F. MORRIS (2000): A leucine to proline mutation in puroindoline b is frequently present in hard wheats from Northern Europe. Theor. Appl. Genet. 100: 1100-1107. LINDSAY, M. P., L.TAMAS, R.APPELS and J. H. SKERRITT (2000): Direct evidence that the number and location of cysteine residues affect glutenin polymer structure. J.Cereal Sci. 31: 321-333. LUO, C., W.B.GRIFFIN, G.BRANLARD and D.L. MCNEIL (2001): Comparison of a low- and high-molecularweight wheat glutenin allele effects on flour quality. Theor. Appl. Genet. 102: 1088-1098. MA, W., W.ZHANG and K.R. GALE (2003): Miltiplex-PCR typing of high molecular weight glutenin alleles in wheat. Euphytica, 134: 51-60. MARTIN, J.M., R.C.FROHBERG, C.F. MORRIS, L.E. TALBERT and M.J. GIROUX (2001): Milling and bread making traits associated with puroindoline sequence type in hard red spring wheat. Crop Sci., 41: 228-234 PAYNE P .I. (1987): Genetic of wheat storage proteins and the effect of allelic variation on bread-making quality. Ann. Rev. Plant Physiol. 38: 141-153. OBREHT, D. (2005): Genetička evaluacija komponenti tehnološkog kvaliteta pšenice primenom molekularnih markera. Doktorska disertacija, Univerzitet u Novom Sadu, Prirodnomatematički fakultet.

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and M. DAVIDOVIĆ (2002): HMW glutenin diversity in hexaploid wheats. Proc. 4th International Symposium Young people and multidisciplinary research, Romania, 507-515. OBREHT, D., S.DENCIC, M.DAVIDOVIĆ and LJ. VAPA (2004): Allelic variability at the Pina-D1 and the Pinb-D1 loci in Serbian hexaploid wheat cultivars. Proceedings of XXXIV Annual Meeting of ESNA (European Society for New Methods in Agricultural Research, Novi Sad, Serbia and Montenegro: 278 – 281. OBREHT, D., B.KOBILJSKI, S.DENCIC, M.DJAN and LJ. VAPA (2006): Potential uses of microsatellites in Marker-Assisted Selection for Improved Bread-Making Quality in Wheat. Cereal Res. Commun. 34: 895-902. RODER, M.S., V.KORZUN, K.WENDEHAKE, J.PLASCHKE, M-H.TIXIER, P.LEROY and M.W. GANAL (1998): A microsatellite map of wheat. Genetics 149: 2007-2023. OBREHT, D, LJ.VAPA

RODER, M.S., W K.ENDEHAKE, V.KORZUN, G.BREDEMEIJER, D.LABORIE, L.BERTRAND, P.ISAAC, S.RENDELL, S.JACKSON, J.COOKE R., B.VOSMAN

and M.W. GANAL (2002): Construction and analysis of a microsatellite-based database of European wheat varieties. Theor. Appl. Genet. 106: 67-73. SHING, N.K. and K.W. SHEPERD (1988: Linkage mapping of genes controlling endosperm storage proteins in wheat. 1. Genes on the short arms of group-1 chromosomes. Theor. Appl. Genet. 75: 628-641. TANURDZIC, M., D.OBREHT, LJ.VAPA and M. DAVIDOVIC (2004): Polyglutamine-encoding microsatellite contributes to LMW GS diversity in Triticum monococcum. Cereal Res. Commun. 32: 301308. VAPA, LJ., S.DENČIĆ, E.ŠOLTES-RAK and S.KEVREŠAN (1995): Genetic variation in Glu-1 loci and breadmaking quality in wheat. Cereal Res. Commun. 23: 161-166. VAPA, LJ., D.OBREHT, M.DJAN, D.KAČAVENDA and B. KOBILJSKI (2004): Korelacija tehnoloških pokazatelja kvaliteta hleba i Glu-1 kvalitetne vrednosti pšenice. Zbornik radova PMF, serija za biologiju 33: 66-73. ZHANG, W., M.C. GIANIBELLI, L.RAMPLING and GALE (2004): Characterisation and marker development for low molecular weight K.R. glutenin genes from Glu-A3 alleles of bread wheat (Triticum aestivum L.). Theor. Appl. Genet. 108: 1409-1419.

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MARKER ASISTIRANA SELEKCIJA U OPLEMENJIVANJU PŠENICE NA KVALITET Dragana OBREHT 1, Borislav KOBILJSKI 2, Mihajla ĐAN 1 i Ljiljana VAPA 1 1

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Prirodno-matematički fakultet, Novi Sad Institut za ratarstvo i povrtarstvo, Novi Sad Izvod

Implementacija marker asistirane selekcije (MAS) u oplemenjivačke programe omogućava procenu genetičkog potencijala genotipa bez potrebe za predhodnom fenotipskom evaluacijom. Mehanizami koji čine biohemijsku bazu tehnološkog kvaliteta pšenice danas su dobro proučeni. Pored toga, naučnoj javnosti su dostupni podaci o DNK sekvencama gena koji kodiraju funkcionalne proteine glutena, kao i tehnike PCR-zasnovanih markera. Sve ovo omogućava razvijanje serije dijagnostičkih DNK markera za polje proučavanja tehnološkog kvaliteta pšenice. Rezultat oplemenjvačkih programa pšenice Instituta za ratarstvo i povrtarstvo u Novom Sadu je veliki broj visoko kvalitetnih sorti namenjenih proizvodnji hleba. Tokom posledjih dvadeset godina u programima oplemenjivanja na kvalitet pored praćenja osnovnih komponenti tehnološkog kvaliteta korišteni su i podaci o kompoziciji glutenina velike molekulske mase (HMW GS). U cilju unapredjenja domaćih oplemenjivačkih strategija razvija se i primena različitih PCR-zasnovanih markera. Cilj ovog rada je pregled tipova dijagnostičkih markera koji se trenutno koriste u inostranim i domaćim selekcionim programima.

Primljeno 18. I. 2008. Odobreno 04. III. 2008.