[Show abstract][Hide abstract] ABSTRACT: Upland cotton (Gossypium hirsutum L.) accounts for about 95% of world cotton production. Improving Upland cotton cultivars has been the focus of world-wide cotton breeding programs. Negative correlation between yield and fiber quality is an obstacle for cotton improvement. Random-mating provides a potential methodology to break this correlation. The suite of fiber quality traits that affect the yarn quality includes the length, strength, maturity, fineness, elongation, uniformity and color. Identification of stable fiber quantitative trait loci (QTL) in Upland cotton is essential in order to improve cotton cultivars with superior quality using marker-assisted selection (MAS) strategy.
[Show abstract][Hide abstract] ABSTRACT: Acetolactate synthase (ALS) is responsible for a rate-limiting step in the synthesis of essential branched-chain amino acids. Resistance to ALS-inhibiting herbicides, such as trifloxysulfuron sodium (Envoke®), can be due to mutations in the target gene itself. Alternatively, plants may exhibit herbicide tolerance through reduced uptake and translocation or increased metabolism of the herbicide. The diverse family of cytochrome P450 proteins has been suggested to be a source of novel herbicide metabolism in both weed and crop plants. In this study we generated a mapping population between resistant and susceptible cotton (Gossypium hirsutum L.) cultivars. We found that both cultivars possess identical and sensitive ALS sequences; however, the segregation of resistance in the F2 progeny was consistent with a single dominant gene. Here we report the closely linked genetic markers and approximate physical location on chromosome 20 of the source of Envoke herbicide susceptibility in the cotton cultivar Paymaster HS26. There are no P450 proteins in the corresponding region of the G. raimondii Ulbr. genome, suggesting that an uncharacterized molecular mechanism is responsible for Envoke herbicide tolerance in G. hirsutum. Identification of this genetic mechanism will provide new opportunities for exploiting sulfonylurea herbicides for management of both weeds and crop plants.
[Show abstract][Hide abstract] ABSTRACT: The untapped potential of the beneficial alleles from Gossypium barbadense L. has not been well utilized in G. hirsutum L. (often referred to as Upland cotton) breeding programs. This is primarily due to genomic incompatibility and technical challenges associated with conventional methods of interspecific introgression. In this study, we used a hypoaneuploid-based chromosome substitution line as a means for systematically introgressing G. barbadense doubled-haploid line '3-79' germplasm into a common Upland genetic background, inbred 'Texas marker-1' ('TM-1'). We reported on the chromosomal effects, lint percentage, boll weight, seedcotton yield and lint yield in chromosome substitution CS-B (G. barbadense L.) lines. Using an additive-dominance genetic model, we studied the interaction of alleles located on two alien substituted chromosomes versus one alien substituted chromosome using a partial diallel mating design of selected CS-B lines (CS-B05sh, CS-B06, CS-B09, CS-B10, CS-B12, CS-B17 and CS-B18). Among these parents, CS-B09 and CS-B10 were reported for the first time. The donor parent 3-79, had the lowest additive effect for all of the agronomic traits. All of the CS-B lines had significant additive effects with boll weight and lint percentage. CS-B10 had the highest additive effects for lint percentage, and seedcotton and lint yield among all of the lines showing a transgressive genetic mode of inheritance for these traits. CS-B09 had greater additive genetic effects on lint yield, while CS-B06, CS-B10 and CS-B17 had superior additive genetic effects on both lint and seedcotton yield compared to TM-1 parent. The 3-79 line had the highest dominance effects for boll weight (0.513 g) and CS-B10 had the lowest dominance effect for boll weight (-0.702). Some major antagonistic genetic effects for the agronomic traits were present with most of the substituted chromosomes and chromosome arms, a finding suggested their recalcitrance to conventional breeding efforts. The results revealed that the substituted chromosomes and arms of 3-79 carried some cryptic beneficial alleles with potential to improve agronomic traits including yield, whose effects were masked at the whole genome level in 3-79.
Theoretical and Applied Genetics 09/2012; · 3.51 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Genetic expression of a trait is complicated and it is usually associated with many genes including their interactions (epistasis) and genotype-by-environment interactions. Genetic mapping currently focuses primarily on additive models or marginal genetic effects due to the complexity of epistatic effects. Thus, there exists a need to appropriately identify favorable epistatic effects for important biological traits. Several multifactor dimensionality reduction (MDR) based methods are important resources to identify high-order gene–gene interactions. These methods are mainly focused on human genetic studies. Many traits in plant systems are not only quantitatively inherited but also are often measured in repeated field plots under multiple environments. In this study, we proposed a mixed model based MDR approach, which is suitable for inclusion of various fixed and random effects. This approach was used to analyze a cotton data set that included eight agronomic and fiber traits and 20 DNA markers. The results revealed high order epistatic effects were detected for most of these traits using this modified MDR approach.
[Show abstract][Hide abstract] ABSTRACT: Genetic data collected from various plant breeding and genetic studies may not be replicated in field designs although field variation is always present. In this study, we addressed this problem using spring wheat (Triticum aestivum L.) trial data collected from two locations. There were no intralocation replications and an extended additive-dominance (AD) model was used to account for field variation. We numerically evaluated the data from simulations and estimated the variance components. For demonstration purposes we also analyzed three agronomic traits from the actual spring wheat data set. Results showed that these data could be effectively analyzed using an extended AD model, which was more comparable to a conventional AD model. Actual data analysis revealed that grain yield was significantly influenced by systematic field variation. Additive effects were significant for all traits and dominance effects were significant for plant height and time-to-flowering. Genetic effects were predicted and used to demonstrate that most spring wheat lines developed by the South Dakota State University breeding program (SD lines) exhibited good general combining ability effects for yield improvement. Thus, this study provides a general framework to appropriately analyze data in situations where field crop data are collected from non-replicated designs.
[Show abstract][Hide abstract] ABSTRACT: Cotton (Gossypium hirsutum L) cultivars highly resistant to the southern root-knot nematode (RKN) [Meloidogyne incognita (Kofoid and White) Chitwood] are not available. Resistant germplasm lines are available; however, the difficulty of selecting
true breeding lines has hindered applied breeding and no highly resistant cultivars are available to growers. Recently, molecular
markers on chromosomes 11 and 14 have been associated with RKN resistance, thus opening the way for marker assisted selection
(MAS) in applied breeding. Our study aimed to determine the utility of these markers for MAS. Cross one was RKN resistant
germplasm M240 RNR × the susceptible cultivar, FM966 and is representative of the initial cross a breeder would make to develop
a RKN resistant cultivar. Cross two consists of Clevewilt 6 × Mexico Wild (PI563649), which are the two lines originally used
to develop the first highly RKN resistant germplasm. Mexico Wild is photoperiodic. We phenotyped the F2 of cross one for gall index and number of RKN eggs per plant and genotyped each plant for CIR 316 (chromosome 11) and BNL
3661 (chromosome 14). From this, we verified that MAS was effective, and the QTL on chromosome 14 was primarily associated
with a dominant RKN resistance gene affecting reproduction. In the first F2 population of cross two, we used MAS to identify 11 plants homozygous for the markers on chromosomes 11 and 14, and which
also flowered in long days. Progeny of these 11 plants were phenotyped for RKN gall index and egg number and confirmed as
RKN highly resistant plants. Generally about 7–10 generations of RKN phenotyping and progeny testing were required to develop
the original RKN highly resistant germplasms. Our results show that commercial breeders should be able to use the markers
in MAS to rapidly develop RKN resistant cultivars.
[Show abstract][Hide abstract] ABSTRACT: Efficient construction of large-scale linkage maps is highly desired in current gene mapping projects. To evaluate the performance of available approaches in the literature, four published methods, the insertion (IN), seriation (SER), neighbor mapping (NM), and unidirectional growth (UG) were compared on the basis of simulated F(2) data with various population sizes, interferences, missing genotype rates, and mis-genotyping rates. Simulation results showed that the IN method outperformed, or at least was comparable to, the other three methods. These algorithms were also applied to a real data set and results showed that the linkage order obtained by the IN algorithm was superior to the other methods. Thus, this study suggests that the IN method should be used when constructing large-scale linkage maps.
Theoretical and Applied Genetics 05/2011; 123(4):649-55. · 3.51 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Genetic diversity is the foundation of any crop improvement program, but the most cultivated Upland cotton [Gossypium hirsutum L., 2n = 52, genomic formula 2(AD)(1)] has a very narrow gene pool resulting from its evolutionary origin and domestication history. Cultivars of this cotton species (G. hirsutum L.) are prized for their combination of exceptional yield, other agronomic traits, and good fiber properties, whereas the other cultivated 52-chromosome species, G. barbadense L. [2n = 52, genomic formula 2(AD)(2)], is widely regarded as having the opposite attributes. It has exceptionally good fiber qualities, but generally lower yield and less desirable agronomic traits. Breeders have long aspired to combine the best attributes of G. hirsutum and G. barbadense, but have had limited success. F(1) hybrids are readily created and largely fertile, so the limited success may be due to cryptic biological and technical challenges associated with the conventional methods of interspecific introgression. We have developed a complementary alternative approach for introgression based on chromosome substitution line, followed by increasingly sophisticated genetic analyses of chromosome-derived families to describe the inheritance and breeding values of the chromosome substitution lines. Here, we analyze fiber quality traits of progeny families from a partial diallel crossing scheme among selected chromosome substitution lines (CS-B lines). The results provide a more detailed and precise QTL dissection of fiber traits, and an opportunity to examine allelic interaction effects between two substituted chromosomes versus one substituted chromosome. This approach creates new germplasm based on pair wise combinations of quasi-isogenic chromosome substitutions. The relative genetic simplicity of two-chromosome interactions departs significantly from complex or RIL-based populations, in which huge numbers of loci are segregating in all 26 chromosome pairs. Data were analyzed according to the ADAA genetic model, which revealed significant additive, dominance, and additive-by-additive epistasis effects on all of the fiber quality traits associated with the substituted chromosome or chromosome arm of CS-B lines. Fiber of line 3-79, the donor parent for the substituted chromosomes, had the highest Upper Half Mean length (UHM), uniformity ratio, strength, elongation, and lowest micronaire among all parents and hybrids. CS-B16 and CS-B25 had significant additive effects for all fiber traits. Assuming a uniform genetic background of the CS-B lines, the comparative analysis of the double-heterozygous hybrid combinations (CS-B × CS-B) versus their respective single heterozygous combinations (CS-B × TM-1) demonstrated that interspecific epistatic effects between the genes in the chromosomes played a major role in most of the fiber quality traits. Results showed that fiber of several hybrids including CS-B16 × CS-B22Lo, CS-B16 × CS-B25 and CS-B16 × TM-1 had significantly greater dominance effects for elongation and hybrid CS-B16 × CS-B17 had higher fiber strength than their parental lines. Multiple antagonistic genetic effects were also present for fiber quality traits associated with most of the substituted chromosomes and chromosome arms. Results from this study highlight the vital importance of epistasis in fiber quality traits and detected novel effects of some cryptic beneficial alleles affecting fiber quality on the 3-79 chromosomes, whose effects were not detected in the 3-79 parental lines.
Theoretical and Applied Genetics 02/2011; 122(7):1351-61. · 3.51 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The identification of molecular markers that are closely linked to gene(s) in Gossypium barbadense L. accession GB713 that confer a high level of resistance to reniform nematode (RN), Rotylenchulus reniformis Linford & Oliveira, would be very useful in cotton breeding programs. Our objectives were to determine the inheritance of RN resistance in the accession GB713, to identify SSR markers linked with RN resistance QTLs, and to map these linked markers to specific chromosomes. We grew and scored plants for RN reproduction in the P(1), P(2), F(1), F(2), BC(1)P(1), and BC(1)P(2) generations from the cross of GB713 × Acala Nem-X. The generation means analysis using the six generations indicated that one or more genes were involved in the RN resistance of GB713. The interspecific F(2) population of 300 plants was genotyped with SSR molecular markers that covered most of the chromosomes of Upland cotton (G. hirsutum L.). Results showed two QTLs on chromosome 21 and one QTL on chromosome 18. One QTL on chromosome 21 was at map position 168.6 (LOD 28.0) flanked by SSR markers, BNL 1551_162 and GH 132_199 at positions 154.2 and 177.3, respectively. A second QTL on chromosome 21 was at map position 182.7 (LOD 24.6) flanked by SSR markers BNL 4011_155 and BNL 3279_106 at positions 180.6 and 184.5, respectively. Our chromosome 21 map had 61 SSR markers covering 219 cM. One QTL with smaller genetic effects was localized to chromosome 18 at map position 39.6 (LOD 4.0) and flanked by SSR markers BNL 1721_178 and BNL 569_131 at positions 27.6 and 42.9, respectively. The two QTLs on chromosome 21 had significant additive and dominance effects, which were about equal for each QTL. The QTL on chromosome 18 showed larger additive than dominance effects. Following the precedent set by the naming of the G. longicalyx Hutchinson & Lee and G. aridum [(Rose & Standley) Skovsted] sources of resistance, we suggest the usage of Ren (barb1) and Ren (barb2) to designate these QTLs on chromosome 21 and Ren (barb3) on chromosome 18.
Theoretical and Applied Genetics 02/2011; 122(2):271-80. · 3.51 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Molecular markers closely linked to genes that confer a high level of resistance to root-knot nematode (RKN) [Meloidogyne incognita (Kofoid & White) Chitwood] in cotton (Gossypium hirsutum L.) germplasm derived from Auburn 623 RNR would greatly facilitate cotton breeding programs. Our objectives were to identify simple sequence repeat (SSR) markers linked to RKN resistance quantitative trait loci (QTL) and map these markers to specific chromosomes. We developed three recombinant inbred line (RIL) populations by single seed descent from the crosses of RKN-resistant parents M-240 RNR (M240), developed from the Auburn 623 RNR source, moderately resistant Clevewilt 6 (CLW6), one of the parents of Auburn 623 RNR, and susceptible parent Stoneville 213 (ST213). These crosses were CLW6 × ST213, M240 × CLW6, and M240 × ST213. RILs from these populations were grown under greenhouse conditions, inoculated with RKN eggs, scored for root gall index, eggs plant(-1), and eggs g(-1) root. Plants were also genotyped with SSR markers. Results indicated that a minimum of two major genes were involved in the RKN resistance of M240. One gene was localized to chromosome 11 and linked to the marker CIR 316-201. This CIR 316-201 allele was also present in CLW6 but not in Mexico Wild (MW) (PI593649), both of which are parents of Auburn 623 RNR. A second RKN resistance gene was localized to the short arm of chromosome 14 and was linked to the SSR markers BNL3545-118 and BNL3661-185. These two marker alleles were not present in CLW6 but were present in MW. Our data also suggest that the chromosome 11 resistance QTL primarily affects root galling while the QTL on chromosome 14 mediates reduced RKN egg production. The SSRs identified in this study should be useful to select plants with high levels of RKN resistance in segregating populations derived from Auburn 623 RNR.
Theoretical and Applied Genetics 11/2010; 121(7):1323-37. · 3.51 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Determination of chromosomes or chromosome arms with desirable genes in different inbred lines and/or crosses should provide useful genetic information for crop improvement. In this study, we applied a modified additive-dominance model to analyze a data set of 13 cotton chromosome substitution lines and their recurrent parent TM-1, five commercial cultivars, and their 70 F(2) hybrids. The chromosome additive and dominance variance components for eight agronomic and fiber traits were determined. On average, each chromosome or chromosome arm was associated with 6.5 traits in terms of additive and/or dominance effects. The chromosomes or chromosome arms, which contributed significant additive variances for the traits investigated, included 2, 16, 18, 25, 5sh (short arm), 14sh, 15sh, 22sh, and 22Lo (long arm). Chromosome additive effects were also predicted in this study. The results showed that CS-B 25 was favorably associated with several fiber traits, while FM966 was favorably associated with both yield and fiber traits with alleles on multiple chromosomes or chromosome arms. Thus, this study should provide valuable genetic information on pure line development for several improved traits such as yield and fiber quality.
[Show abstract][Hide abstract] ABSTRACT: Seed from upland cotton, Gossypium hirsutum L., provides a desirable and important nutrition profile. In this study, several seed traits (protein content, oil content, seed hull fiber content, seed index, seed volume, embryo percentage) for F(3) hybrids of 13 cotton chromosome substitution lines crossed with five elite cultivars over four environments were evaluated. Oil and protein were expressed both as percentage of total seed weight and as an index which is the grams of product/100 seeds. An additive and dominance (AD) genetic model with cytoplasmic effects was designed, assessed by simulations, and employed to analyze these seed traits. Simulated results showed that this model was sufficient for analyzing the data structure with F(3) and parents in multiple environments without replications. Significant cytoplasmic effects were detected for seed oil content, oil index, seed index, seed volume, and seed embryo percentage. Additive effects were significant for protein content, fiber content, protein index, oil index, fiber index, seed index, seed volume, and embryo percentage. Dominance effects were significant for oil content, oil index, seed index, and seed volume. Cytoplasmic and additive effects for parents and dominance effects in homozygous and heterozygous forms were predicted. Favorable genetic effects were predicted in this study and the results provided evidence that these seed traits can be genetically improved. In addition, chromosome associations with AD effects were detected and discussed in this study.
Theoretical and Applied Genetics 05/2010; 120(7):1473-83. · 3.51 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: We recently released a set of 17 chromosome substitution (CS-B) lines (2n = 52) that contain Gossypium barbadense L. doubled-haploid line '3-79' germplasm systematically introgressed into the Upland inbred 'TM-1' of G. hirsutum (L.). TM-1 yields much more than 3-79, but cotton from the latter has superior fiber properties. To explore the use of these quasi-isogenic lines in studying gene interactions, we created a partial diallel among six CS-B lines and the inbred TM-1, and characterized their descendents for lint percentage, boll weight, seedcotton yield and lint yield across four environments. Phenotypic data on the traits were analyzed according to the ADAA genetic model to detect significant additive, dominance, and additive-by-additive epistasis effects at the chromosome and chromosome-by-chromosome levels of CS-B lines. For example, line 3-79 had the lowest boll weight, seedcotton yield and lint yield, but CS-B22Lo homozygous dominance genetic effects on seedcotton and lint yield were nearly four times those of TM-1, and its hybrids with TM-1 had the highest additive-by-additive epistatic effects on seedcotton and lint yield. CS-B14sh, 17, 22Lo and 25 produced positive homozygous dominance effects on lint yield, whereas doubly heterozygous combinations of CS-B14sh with CS-B17, 22Lo and 25 produced negative dominance effects, suggesting that epistatic effects between genes in these chromosomes strongly affect lint yield. The results underscore the opportunities to systematically identify genomic regions harboring genes that impart agronomically significant effects via epistatic interactions. The chromosome-by-chromosome approach significantly complements other strategies to detect and quantify epistatic interaction effects, and the quasi-isogenic nature of families and lines from CS-B intermatings will facilitate high-resolution localization, development of markers for selection and map-assisted identification of genes involved in strong epistatic effects.
Theoretical and Applied Genetics 04/2010; 120(6):1193-205. · 3.51 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: This research detected QTL or molecular markers associated with yield, fiber, and seed traits within multiple fuzz and fiber loci genetic backgrounds. Two F₂ populations from crosses of MD17, a fuzzless-lintless line containing three fuzzless loci, N ₁ , n ₂ and a postulated n ₃ , with line 181, fuzzless-linted and with FM966, a fuzzy-linted cultivar, were used. QTL explaining 68.3 (population with FM966) to 87.1% (population with 181) of the phenotypic variation for lint percentage and 62.8% (population with 181) for lint index were detected in the vicinity of BNL3482-138 on chromosome 26. Single marker regression analyses indicated STV79-108, on the long arm of chromosome 12 had significant association with lint percentage (R ² 26.7%), lint index (R ² 30.6%), embryo protein percentage (R ² 15.4%) and micronaire (R ² 20.0%). Two-locus epistatic interactions were also observed. Results from this research will facilitate further understanding the complex mechanisms of yield, fiber, and seed traits of cotton.
[Show abstract][Hide abstract] ABSTRACT: With 5 tables As new technology in the textile industry demands higher quality fibres, improving cotton fibre quality has become increasingly important. Twelve cotton lines selected from different breeding programmes with diverse fibre characteristics were used for this study. These lines and their F₂ hybrids were grown at the Mississippi State University research farm in three environments. Agronomic and fibre traits were measured and analysed by the additive-dominance genetic model. Significant additive effects were detected for all traits except seed cotton yield and fibre elongation. Dominance effects were significant for all traits. All MD lines and CS-B16 showed positive additive effects for lint percentage (LP), indicating that these lines can be used as general combiners to improve LP. MD90ne was a good general combiner for cotton yield. MD51ne, MD52ne, MD90ne and three derived day-neutral lines were associated with increased additive effects for fibre strength. Some F₂ hybrids with positive middle-parent heterosis for both yield and fibre quality were identified. This study revealed that these genetic lines can be used for inbred line and/or hybrid development.
[Show abstract][Hide abstract] ABSTRACT: Selecting high yielding upland cotton, Gossypium hirsutum L. lines with improved fiber quality is a primary breeding goal. A diverse set of ten cultivars and one breeding line were crossed in a half diallel. Parents and F₂ hybrids were grown in three environments at Mississippi State, MS. Ten agronomic and fiber traits were analyzed by a mixed linear model approach based on the additive-dominance genetic model. Variance component, genetic effects and genetic correlations were calculated. 'Acala Ultima' was a desirable general combiner for fiber length, uniformity, strength, micronaire, lint percentage, and boll weight. 'FiberMax 966' was a desirable general combiner for fiber length, uniformity, strength, and all agronomic traits. 'Tamcot Pyramid' and M240 were poor general combiners for both fiber and agronomic traits. 'Coker 315' was a good general combiner for fiber length, uniformity, micronaire, boll weight, boll number, and yield. Heterozygous dominance effects were associated with several crosses, which suggest their use as hybrids.
[Show abstract][Hide abstract] ABSTRACT: Investigation of cotton nutritional components is important because its seeds provide a useful nutritional profile and can possibly serve as a biofuel resource. In this study, five cultivars, 13 cotton chromosome substitution (CS-B) lines, their donor parent, '3-79', and their recurrent parent, 'TM-1', were evaluated for seed traits over four environments. A mixed linear model approach with the jackknife method was employed to estimate variance components and to predict genotypic effects for each seed trait. Genotypic effects were more important than genotype by environment interaction for all seed traits. Chromosome associations with these seed traits were detected using the comparative method by comparing the differences between each CS-B line and TM-1. For example, chromosome 4 of 3-79 in TM-1 background was associated with reduced seed index (SI), embryo percentage, protein percentage while associated with increased seed oil percentage and seed fiber percentage. Other chromosome associations with these seed traits were also observed in this study. SI was highly correlated with three seed index traits: seed protein index, seed oil index (OI), and seed fiber index. Lint percentage, boll number, and lint yield were positively correlated with protein percentage while negatively correlated with SI and OI. SI and seed fiber content exhibited negative correlations with micronaire but positive correlations with fiber length and strength. Results suggested that agronomic traits and seed nutrition components can be improved simultaneously.
[Show abstract][Hide abstract] ABSTRACT: A combination of previously mapped and unmapped non-redundant SSR loci, using 381 primer pairs were chromosomally and sub-chromosomally localized by deficiency analysis of two sets of quasi-isogenic interspecific Gossypium hirsutum L. hypoaneuploid F₁ hybrids involving Gossypium barbadense L. and Gossypium tomentosum (Nuttall ex Seemann). Polymorphisms were detected for 369 SSR primer pairs. A total of 318 SSR loci were rendered deficient by the available hypoaneuploid stocks, which included primary monosomics (2n = 51), monotelodisomics and duplication-deficient (segmental trisomic-monosomic) (2n = 52) types. Chromosomal associations were newly determined for 123 SSR loci, of which 90, 106 and 73 were polymorphic in G. tomentosum, G. barbadense, and both sets, respectively. The deficiency tests independently confirmed the recent identifications of linkage groups (LG) A01, A02, A03 and D08 to be chromosome (Chr)-13, Chr-8, Chr-11 and Chr-19, respectively, and collectively delimited LG D02 and D03 to Chr-21 and 24, and their homeologs to Chr-8 and 11. Segmental homeology was detected between Chr-2 and Chr-17 loci, adding to evidence of segmental homeology between Chr-2 and 3 versus Chr-14 and 17. The 318 non-redundant SSR loci localized in this study will enhance the construction of linkage maps and QTL identification in molecular marker assisted selection since the confirmed and newly discovered SSR loci can serve as anchor loci for their respective chromosomes.