Download or read book Genetic Mapping of Quantitative Trait Loci for Slow rusting Traits in Wheat written by Yue Lu and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Wheat leaf rust, caused by Puccinia triticina, is an important fungal disease worldwide. Growing resistant cultivars is an effective practice to reduce the losses caused by the disease, and using slow-rusting resistance genes can improve the durability of rust resistance in the cultivars. CI13227 is a winter wheat line that shows a high level of slow-rusting resistance to leaf rust and has been studied extensively. In this research, two recombinant inbreed line (RIL) populations derived from CI13227 x Suwon (104 RILs) and CI13227 x Everest (184 RILs) and one doubled haploid (DH) population derived from CI13227 x Lakin with 181 lines were used to identify quantitative trait loci (QTLs) for slow leaf rusting resistance. Each population and its parents were evaluated for slow-rusting traits in two greenhouse experiments. A selected set of 384 simple sequence repeat markers (SSRs), single nucleotide polymorphism markers (SNPs) derived from genotyping-by-sequencing (GBS-SNPs) or 90K-SNP chip (90K-SNPs) were analyzed in the three populations. Six QTLs for slow-rusting resistance, QLr.hwwgru-2DS, QLr.hwwgru-7BL, QLr.hwwgru-7AL, QLr.hwwgru-3B_1, QLr.hwwgru-3B_2, and QLr.hwwgru-1D were detected in the three populations with three stable QTLs, QLr.hwwgru-2DS, QLr.hwwgru-7BL and QLr.hwwgru-7AL. These were detected and validated by Kompetitive Allele-Specific PCR (KASP) markers converted from GBS-SNPs and 90K-SNPs in at least two populations. Another three QTLs were detected only in a single population, and either showed a minor effect or came from the susceptible parents. The KASP markers tightly linked to QLr.hwwgru-2DS (IWB34642, IWB8545 and GBS_snpj2228), QLr.hwwgru-7BL (GBS_snp1637 and IWB24039) and QLr.hwwgru-7AL (IWB73053 and IWB42182) are ready to be used in marker-assisted selection (MAS) to transfer these QTLs into wheat varieties to improve slow-rusting resistance in wheat.

Download or read book Quantitative Trait Loci Mapping of Rust Resistance and Agronomic Traits in the Doubled Haploid Spring Wheat Population HYAYT12 10 GP146 written by Izabela L. Ciechanowska and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Marker-assisted selection requires the identification of molecular markers associated with major genes and quantitative trait loci (QTL) using linkage analysis. In this study, we used 167 doubled haploid (DH) lines derived from two unregistered spring wheat (Triticum aestivum L.) parental lines that belong to the Canada Western Special Purpose (CWSP) class to map QTLs associated with five traits using inclusive composite interval mapping (ICIM). Using ICIM, least square means phenotype data across 3-4 environments, and a genetic map of 2,676 SNPs out of the wheat 90K SNP array, we identified ten QTLs associated with maturity (4A and 5B), plant lodging (4B, 5A, 5D, and 7D), grain yield (2D), leaf rust (4A) and stem rust (1A and 2B). Each QTL individually accounted for 6.0-22.3% of the phenotypic variance and together accounted for 8.6-38.2% of each trait. QTLs identified for rusts using ICIM had a minor effect (6.0-9.0%) or a major effect (22.3%). Our major effect QTL at 22.3% was discovered on chromosome 2B and contributed to stem rust response. Its physical location has been associated with disease response in previous studies. Results from this study provide additional valuable information to wheat researchers, in particular that the area on chromosome 2B should be considered for future analyses.

Download or read book Stripe Rust written by Xianming Chen and published by Springer. This book was released on 2017-07-11 with total page 723 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book comprehensively introduces stripe rust disease, its development and its integral control. Covering the biology, genetics, genome, and functional genomics of the pathogen, it also discusses host and non-host resistance, their interactions and the epidemiology of the disease. It is intended for scientists, postgraduates and undergraduate studying stripe rust, plant pathology, crop breeding, crop protection and agricultural science, but is also a valuable reference book for consultants and administrators in agricultural businesses and education.

Download or read book Inheritance and Quantitative Trait Loci Analysis of Leaf Rust Resistance in Wheat written by Julia Xiuling Zhang and published by . This book was released on 2007 with total page 226 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Genetic Analyses of Wheat and Molecular Marker Assisted Breeding Volume 2 written by Jichun Tian and published by Springer. This book was released on 2015-11-25 with total page 338 pages. Available in PDF, EPUB and Kindle. Book excerpt: While focusing on various interactions between trait genes/QTL and dynamic expressions of conditional QTL genes, this book also discusses aspects of molecular marker-assisted breeding, and applications of molecular markers associated with yield, quality, physiology and disease resistance in wheat. It covers QTL studies in wheat breeding and presents the available information on wheat MAS breeding. This volume provides a wealth of novel information, a wide range of applications and deep insights into crop genetics and molecular breeding, which is valuable not only for plant breeders but also for academic faculties, senior researchers and advanced graduate students who are involved in plant breeding and genetics. Dr. Jichun Tian is a professor at the Department of Agronomy, Shandong Agricultural University, Tai’an, China.

Download or read book Identification and Mapping of Genes Controlling Several Traits of Wheat Using Restriction Fragment Length Polymorphism RFLP Markers written by Zhengqiang Ma and published by . This book was released on 1994 with total page 270 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Breeding Strategies for Resistance to the Rusts of Wheat written by International Maize and Wheat Improvement Center and published by CIMMYT. This book was released on 1988 with total page 164 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book QTL Mapping of Stem Rust Resistance Loci in Durum Wheat Populations written by Shitaye Homma Megerssa and published by . This book was released on 2021 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Stem rust caused by Puccinia graminis f. sp. tritici Eriks. & Henn is the most destructive disease of durum and common wheat. The main focus of this study is to identify loci associated with stem rust resistance in durum wheat using association mapping and linkage mapping. A panel of 283 lines and 224 recombinant inbred lines (RILs) from a cross between 'Reichenbachii' and 'DAKIYE' developed by the durum wheat breeding program of the International Maize and Wheat Improvement Center (CIMMYT) were used for the study. The panel was evaluated against races TTKSK, TKTTF, JRCQC and TTRTF at the seedling stage and TKTTF and JRCQC in the field in Ethiopia from 2018 to 2019 for two seasons. The same panel was evaluated against bulk of multiple stem rust races prevalent in Ethiopia and Kenya from 2018 to 2019 in five environments. Genome-wide association study (GWAS) was conducted using 26,439 single nucleotide polymorphism (SNP) markers for seedling response (280 lines) and field response (283 lines) to stem rust. The RILs along with the two parents were evaluated for response to bulk of multiple stem rust races in Ethiopia and Kenya for two seasons from 2019 to 2020. Linkage analyses were conducted using 843 SNP markers for 175 lines. For GWAS of seedling response, a mixed linear model (MLM) identified 17 quantitative trait loci (QTL) of which eight were putatively novel while FarmCPU identified 20 QTL and 12 were likely novel. For field resistance to races TKTTF and JRCQC, MLM detected 19 QTL of which 12 were likely novel while FarmCPU detected 16 QTL and seven were putatively novel. For resistance to multiple Pgt races in East Africa, 160 significant marker-trait associations (MTAs) grouped into 42 QTL were identified using MLM and FarmCPU and 21 QTL were likely novel. From previously reported Sr genes, the regions of Sr7a, Sr8a, Sr8155B1, Sr11, Sr12, alleles of Sr13, Sr17, Sr22/Sr25, and Sr49 were identified. For the biparental population, composite interval mapping (CIM) identified three QTL on chromosomes 3B (QSr.cnl-3B), 4B (QSr.cnl-4B) and 7B (QSr.cnl-7B). These three QTL contributed by the resistant parent explained 4.7% to 15.3% of the phenotypic variation and all match previously reported loci. Lines with multiple-race stem rust resistance can be used as parents in durum wheat resistance breeding to stem rust and markers identified in the GWAS can be used in marker-assisted selection (MAS) once validated in a different population. Further study on the validation of allele specific markers and allelism tests in the Sr13 region of chromosome 6A is needed. Future evaluation of large numbers of durum wheat lines and searching for durable adult plant resistance gene is crucial in resistance breeding of durum wheat.

Download or read book Genetic Linkage Map Construction and Identification of Quantitative Trait Loci QTLs Determining Post anthesis Drought Tolerance and Other Agronomic Traits in Bread Wheat written by Khalil Zaynali Nezhad and published by . This book was released on 2010 with total page 267 pages. Available in PDF, EPUB and Kindle. Book excerpt: Two bread wheat (T. aestivum L.) accessions were selected as parental lines. Population genotyping was conducted on 143 F2 plants and phenotyping was carried out on 133 F2:3 families. The molecular genetic linkage map was constructed including 293 loci associated to 19 wheat chromosomes. There are 76 new loci compared to the ITMI map. The analysis revealed eight QTLs for days to flowering and seven QTLs for plant height. Five QTLs for spike length were identified. The QTL for seed length on chromosome 5B was mapped for all trait measurements under both conditions. The present study revealed four and six QTLs for thousand-grain weight under control and stress conditions, respectively. Only one QTL on chromosome 4BL was common for both conditions. Five QTLs for thousand-grain weight were found to be specific to stress condition on chromosomes 1B, 4AL, 7AS, and 7DS. Identifying QTLs for thousand-grain weight under post-anthesis drought stress on chromosomes 7DS, 7AS, and 4AL and considering the known reciprocal translocation of 4AL/7BS in wheat, revealed the importance of the chromosomes from the homoeologous group 7 of Triticeae.

Download or read book Genetics and quantitative trait loci mapping of septoria tritici blotch resistance agronomic and quality traits in wheat written by Vibin Eranezhath Harilal and published by . This book was released on 2011 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Quantitative Trait Loci Mapping of Yield Its Related Traits and Spike Morphology Factors in Winter Wheat Triticum Aestivum L written by Robert Christopher Gaynor and published by . This book was released on 2011 with total page 170 pages. Available in PDF, EPUB and Kindle. Book excerpt: Increasing grain yield in wheat (Triticum aestivum L.) is a challenging task, because yield is a complex trait controlled by many genes and highly influenced by environmental factors. The genetic control of yield components and other traits associated with yield may be less complex and thus more manageable for breeding. This study seeks to identify quantitative trait loci (QTLs) for these traits. Two new genetic linkage maps were constructed from recombinant inbred lines (RILs) derived from crosses between the Oregon soft white winter wheat variety Tubbs and a Western European hard red winter wheat variety, Einstein. A third linkage map was constructed from RILs from a cross with Tubbs and a Western European experimental hard red winter wheat line. A combination of Diversity Arrays Technology (DArT), Simple Sequence Repeat (SSR), orw5, and B1 markers were used to construct genetic linkage maps. Two replications of the RIL populations were grown in yield trial sized plots at Corvallis, OR and Pendleton, OR in 2009. The RILs were evaluated for grain yield, spikes per m2, fertile spikelets per spike, sterile spikelets per spike, seeds per spike, seeds per fertile spikelet, average seed weight, growing degree days (GDD) to flowering, GDD to physiological maturity, GDD of grain fill, plant height, test weight, and percent grain protein. Composite interval mapping (CIM) detected 146 QTLs for these traits spread across all chromosomes except for 6D. Thirty six percent of all of the QTLs detected were in close proximity to four loci: Rht-B1, Rht-D1, B1, and Xgwm372. The use of factor analysis to aid in QTL mapping for correlated traits related to spike morphology was explored. Quantitative trait loci mapping of factor scores for these traits potentially showed an increase in statistical power to detect QTLs and a decrease in the probability of type I error over mapping the traits individually.

Download or read book Molecular Characterization of Durable Yellow and Leaf Rust Resistance in Two Wheat Populations written by Bhoja Basnet and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Wheat (Triticum aestivum L.) is one of the most important food crops, comprising the largest source of daily calorie and protein intake of human beings worldwide. Among the several diseases of wheat, Yellow Rust (YR; caused by Puccinia striiformis Westend. f. sp. tritici) and Leaf Rust (LR; caused by Puccinia triticina Erikss. & Henn.) have always been major production constraints since the domestication of wheat. For the last few decades, scientists have invested large efforts to identify, characterize and utilize Adult Plant Resistance (APR), a.k.a. slow rusting resistance, in wheat germplasm to promote durability of resistance against rust. The objectives of this study were to 1) understand the genetics of APR to YR and/or LR present in two potential wheat lines 'Quaiu 3' and 'TAM 111', and 2) map the putative Quantitative Trait Loci (QTL) associated with YR and LR resistance using DNA-based molecular markers. Two Recombinant Inbred Line (RIL) populations were subjected to YR and LR disease evaluation experiments in multiple years and locations. Visual evaluation of Disease severity (DS) and Infection Type (IT) score in both RIL populations showed that APR to YR and LR were highly heritable quantitative traits with significant correlation among experiments. In spring wheat population, composite interval mapping consistently detected four and three large effect QTL for YR and LR resistance, respectively. Among those QTLs, 1B, 3B and 1D QTL were found to be associated with previously characterized genes Lr46/Yr29, Sr2/Yr30 and Lr42, respectively. However, QTLs QYr.tam-3D and QYr.tam-2D were potentially novel. The largest YR QTL QYr.tam-2D was located on long arm of chromosome 2D explaining about 48 to 61% of the total phenotypic variation. Similarly, in winter wheat population, apart from three environment-specific QTL on chromosomes 1A, 2A and 7D, the QTL on chromosome 2B (QYr.tam-2B) was found to express consistently in multiple environments explaining about 23 to 63% of total phenotypic variation. This study has further elucidated the inheritance mechanism of APR to YR and LR present in two different wheat lines, Quaiu 3 and TAM 111, and resulted in the successful mapping and characterization of the genetic loci associated with corresponding disease resistance traits. These findings should be very useful to isolate the novel APR genes and/or directly use in wheat breeding programs to enhance durable rust resistance in diverse wheat germplasm and cultivars in the future.

Download or read book Quantitative Trait Loci Analysis in Animals written by Joel Ira Weller and published by CABI. This book was released on 2009 with total page 288 pages. Available in PDF, EPUB and Kindle. Book excerpt: Quantitative Trait Loci (QTL) is a topic of major agricultural significance for efficient livestock production. This book covers various statistical methods that have been used or proposed for detection and analysis of QTL and marker-and gene-assisted selection in animal genetics and breeding.

Download or read book Quantitative Trait Locus Mapping of Agronomic Physiological and End use Quality Traits of Common Wheat T Aestivum written by Junli Zhang (Doctoral student) and published by . This book was released on 2013 with total page 416 pages. Available in PDF, EPUB and Kindle. Book excerpt: Grain yield (GY) is always the first priority in wheat (Triticum aestivum L.) breeding; however, progress in improvement of this trait is hampered due to quantitative inheritance, low heritability, and confounding environmental effects. Thanks to the advancements of high throughput genotyping and phenotyping technologies, both molecular markers and physiological traits are now promising indirect selection tools in breeding for this trait and other traits. Besides grain yield, grain quality is another important respect in wheat breeding, and one of the quality traits is the Hagberg falling number (FN), which is commonly used in grain grading. The FN test has a genetic component but is also strongly influenced by environmental conditions during the reproductive growth stage, including excessive moisture, extreme temperature, and biotic and abiotic stresses. The objective of the current studies was to identify potential genomic regions and molecular markers that influence GY, three important physiological traits (canopy temperature, CT; chlorophyll content index, CCI; flag leaf senescence, FLS) that could impact grain yield during heat and moisture stress, and FN by QTL mapping approaches. A winter wheat population of 159 recombinant inbred lines (RILs) from the cross of ID0444 and Rio Blanco were used to map QTL for GY, CT, CCI and FLS, and a total of 110 hard white spring (HWS) wheat accessions from the National Small Grain Collection (NSGC) were used in genome-wide association mapping of FN. GY was evaluated under three field conditions, rainfed, terminal drought (water stress applied after anthesis), and fully irrigated, with a total of six location-year environments. QTL mapping was conducted for main effect (G) of GY, and the genotype x environment interaction (GEI) effect of GY. A total of 17 QTL were associated with G and 13 QTL associated with GEI, and nine of 13 QTL for GEI were mapped in the flanking chromosomal regions of QTL for GEI. One QTL, Q.Gy.ui-1B.2 found on chromosome 1B, was associated with GY in all six individual environments. Significant QTL x environment interaction (QEI), QTL x QTL interaction (QQI) and QTL x QTL x environment (QQEI) were also identified. The present study showed that the QEI and QQI were as important as the QTL main effect of GY, and they should be taken into consideration in future QTL studies and marker-assisted selection (MAS). The three physiological traits, CT, CCI and FLS, which have been reported to be closely related to grain yield of wheat in diverse environments, were evaluated in two terminal drought and one rainfed environments in southeastern Idaho. Correlation results showed that CT and FLS were highly correlated with GY but the relationship between CCI and GY varied among the three environments. FLS was closely related to heading date (HD) and its effect on grain yield might be determined by HD in the RIL population used in the study. Stepwise multiple regression showed that CT and FLS could predict grain yield effectively and could be used as indirect selection criteria in wheat breeding. A total of 27 main effect QTL (M-QTL) were identified on 12 chromosomes, explaining 5 to 14% of phenotypic variation. Seven epistatic QTL (E-QTL) were identified for FLS and CCI and these could explain 9-25% of the phenotypic variation, but most of them did not have a main effect. Most of the QTL were reported for the first time. FN tests were conducted using grain flour samples from the 110 HWS wheat accessions grown in five environments. A total of 1,740 SNP markers were used to detect SNP-FN associations using both general linear model (GLM) and mixed linear model (MLM). A total of 13 QTL located in nine chromosomal regions were identified in both GLM and MLM approaches. These new QTL have the potential to increase the selection efficiency for wheat breeding, and can be further explored to identify candidate genes.

Download or read book Identification of Quantitative Trait Loci Underlying Kernel Extra softness and Related Traits by Linkage and Association Mapping in Wheat Triticum Aestivum L written by Guomei Wang and published by . This book was released on 2011 with total page 160 pages. Available in PDF, EPUB and Kindle. Book excerpt: Kernel hardness (KHA) is a major factor determining break flour yield (BFY) and end-use quality of common wheat (Triticum aestivum L.). Within the soft wheat class, genotypes with consistently softer grains than common soft wheat are considered to be 'extra-soft'. In addition, 'extra-soft' wheats have greater BFY than common soft wheat lines. In order to better understand this interrelationship, a set of 164 F6-recombinant inbred lines (RILs) developed from a soft x 'extra-soft' wheat cross was evaluated for KHA, BFY, and other related traits in six field environments. The estimates of broad-sense heritability for KHA and BFY ranged from 0.84 to 0.96 and 0.56 to 0.76, respectively. Significant environmental effects and genotype by environment interactions were detected for all traits evaluated. A comprehensive genetic linkage map was created with 650 molecular markers based on this mapping population. Three chromosome translocations, 1BL. 1RS, 2N^S-2AS. 2AL and 5B:7B, were identified during linkage analysis. A total of 47 quantitative trait loci (QTL) were identified for nine traits including KHA, BFY, bran yield (BRN), unground middling yield (MID), plant height (PHT), days to heading (HDD), thousand-kernel weight (TKW), grain protein content (GPC), and test weight (TWT). The number of QTL per trait ranged from three for MID to nine for GPC. The phenotypic variance explained by individual QTL ranged from 5.8 to 47.6%. Among five QTL identified for KHA, the two most important QTL were located on chromosomes 4DS (Xbarc1118-Rht-D1 interval) and 4BS (Xwmc617-Rht-B1 interval), indicating that the 'extra-soft' characteristic was not controlled by the 5DS Hardness (Ha) locus which encodes the two puroindoline genes pinA and pinB. The co-location of QTL for KHA, BFY, BRN, and MID on 4DS suggested that genetic factors affecting KHA may have a pleiotropic effect on BFY. Two co-located QTL for TWT, TKW and PHT were detected on 4DS and 4BS, and a QTL for HDD was detected on 4DS, indicating that these QTL may represent the consequence of the semi-dwarfing green-revolution genes Rht-D1 and Rht-B1 located on 4DS and 4BS, respectively. Additional analysis suggested that the QTL for KHA on 4DS and 4BS are the effects of genes linked to Rht-D1 and Rht-B1, rather than pleiotropic effects of these genes. Some coincident QTL for the traits that were evaluated represent the interrelationships of phenotypic traits, where both KHA and BFY were associated with HDD and TWT based on path coefficient analysis. Association mapping can be an effective means for identifying, validating, and fine mapping genes and QTL in crop plants. To test this approach, a set of 94 diverse elite wheat lines was phenotyped for five important traits and genotyped with 487 molecular markers. In this study, the marker-trait association analysis showed that the gene pinB (Ha locus) was significantly associated with KHA as it is known to define the difference between soft and hard wheat classes. Additionally, the significant associations of marker XwPt-7187 with KHA, XwPt-1250 and XwPt-4628 with TWT, and Xgwm512 with PHT mark the first report of such associations in these genomic regions. This study, aiming at the genetic dissection of wheat kernel extra-softness and related traits, enhanced our understanding of both genetic control of and environmental effects on these important traits. Path coefficient analysis showed the promise of an alternative phenotypic selection approach that is more cost effective than direct measurement of kernel quality. Three chromosome translocations were discovered and their approximate chromosome break points were located. Numerous QTL were identified for these important traits. The major QTL can serve as a start point for fine mapping that eventually lead to the cloning of the QTL through map-based or candidate gene approach. Association mapping, as an alternate approach and complementary tool to QTL mapping, was demonstrated feasible in wheat for identification of marker-trait associations and cross validation of QTL or genes identified from bi-parent mapping populations.

Download or read book Quantitative Trait Loci written by Nicola J. Camp and published by Boom Koninklijke Uitgevers. This book was released on 2002-04-26 with total page 376 pages. Available in PDF, EPUB and Kindle. Book excerpt: In Quantitative Trait Loci: Methods and Protocols, a panel of highly experienced statistical geneticists demonstrate in a step-by-step fashion how to successfully analyze quantitative trait data using a variety of methods and software for the detection and fine mapping of quantitative trait loci (QTL). Writing for the nonmathematician, these experts guide the investigator from the design stage of a project onwards, providing detailed explanations of how best to proceed with each specific analysis, to find and use appropriate software, and to interpret results. Worked examples, citations to key papers, and variations in method ease the way to understanding and successful studies. Among the cutting-edge techniques presented are QTDT methods, variance components methods, and the Markov Chain Monte Carlo method for joint linkage and segregation analysis.

Download or read book Genetics of Resistance to Leaf and Stripe Rust Diseases in the Spring Wheat Amadina written by Peter Michael Bulli Nyori and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In this research, a recombinant inbred line (RIL) population derived from cross between a leaf rust- and stripe rust-susceptible spring wheat 'Avocet S' and a slow leaf- and stripe-rusting resistant spring wheat 'Amadina' was used to postulate and map leaf rust seedling resistance genes, identify quantitative trait loci (QTL) for slow-rusting resistance against leaf and stripe rust, and study slow leaf-rusting components, latent period and infection frequency. Two known Lr genes (Lr23, and Lr26) were identified to be present in 'Amadina' through gene postulation, pedigree, cytogenetic, and polymerase chain reaction analyses. One unknown gene associated with seedling resistance was also mapped on chromosome 1BL. In greenhouse experiment, it was estimated that at least five genes conditioning final disease severity (FS) and latent period (LP), and four genes conditioning infection frequency (IF), segregated in the population. Correlations between LP and FS, and LP and IF were moderately negative, and that between IF and FS was moderately positive, indicating inter-dependence of the traits. Two QTL on chromosomes 1BL and 6BL were associated with LP and FS, and three QTL on chromosomes 1BL, 6BL and 2DS were associated with IF. Segregation of the RIL population in field experiment indicated that there were at least four and three adult plant resistance (APR) genes involved in resistance for leaf and stripe rust. Six QTL on chromosomes 3AL, 4AL, 1BL, 5BL, and 7BL were associated with APR for leaf rust, and seven QTL on chromosome 4AL, 5AL, 1BL, 2BL, 4BL, 5BL, 2DL, and 4D were associated with APR for stripe rust. Our results indicated that the major portion of genetic variability for slow-rusting resistance was additive gene action, and, to some extent, epistasis. In this research, we also explored the utility of remote sensing and geographic information systems (GIS) and analytical operations to discriminate leaf rust pustules from other parts of leaf and to accurately determine pustule size in 'Amadina' and 'Avocet S'.