Identification of quantitative trait loci for bruchid (<Emphasis Type="Italic">Callosobruchus maculatus</Emphasis>) resistance in black gram [<Emphasis Type="Italic">Vigna mungo</Emphasis> (L.) Hepper]

An inter-subspecific mapping population was generated by crossing V. mungo var. mungo (cv. TU 94-2, bruchid susceptible) and V. mungo var. silvestris (bruchid resistant). About 37.8% of the bruchid completed their lifecycle on seeds of V. mungo var. silvestris compared with 100% on the susceptible variety TU 94-2. The total developmental period of C. maculatus on Vigna mungo var. silvestris was considerably extended (88 days as compared with 34 days on TU 94-2). A genetic linkage map constructed using recombinant inbred lines (RILs) in F₉ generation with 428 markers [86 random amplified polymorphic DNA (RAPD), 47 simple sequence repeat (SSR), 41 inter-SSR (ISSR), 254 amplified fragment length polymorphism (AFLP)] was used for QTL detection. One hundred four individuals were used for detection of QTLs associated with bruchid resistance. The RILs exhibited a high level of variation in percentage adult emergence (0–100%) and developmental period (0–105 days). Two QTLs, Cmrae1.1 and Cmrae1.2, were identified for percentage adult emergence, on linkage group (LG) 3 and 4, respectively. For developmental period, six QTLs were identified, with two QTLs (Cmrdp1.1 and Cmrdp1.2) on LG 1, three QTLs (Cmrdp1.3, Cmrdp1.4, and Cmrdp1.5) on LG 2, and one QTL (Cmrdp1.6) on LG 10.     

Inheritance of Resistance to Yellow Mosaic Virus in some Vigna Species

Inheritance of resistance to Yellow Mosaic Virus (YMV) was studied in crosses of mungbean, black-gram and their interspecific crosses with Vigna sub-lobata. Resistance to YMV was recessive in the three Vigna species. The segregation ratios in F₂ and back crosses indicated that the resistance was digenic recessive in the crosses of mungbean and in interspecific crosses of mungbean with blackgram and Vigna subiobata but YMV resistance was monogenic recessive in blackgram crosses.     

Inheritance and molecular tagging of MYMIV resistance gene in blackgram (Vigna mungo L. Hepper)

Yellow Mosaic disease (YMD) is one of the most destructive diseases of blackgram (Vigna mungo) causing heavy yield losses every year. Mungbean Yellow Mosaic India Virus (MYMIV) is one of the YMD causing begomoviruses prevalent in the major blackgram growing area (northern and central part) of India. Inheritance of MYMIV resistance gene was studied in blackgram using F₁, F₂ and F_2:3 derived from cross DPU 88-31(resistant)× AKU 9904 (susceptible). The results of genetic analysis showed that a single dominant gene controls the MYMIV resistance in blackgram genotype DPU 88-31. The F₂ population from the same cross was also used to tag and map the MYMIV resistance gene using SSR markers. Out of 361 markers, 31 were found polymorphic between the parents. However, marker CEDG 180 was found to be linked with resistance gene following the bulked segregant analysis. This marker was mapped in the F₂ mapping population of 168 individuals at a map distance of 12.9 cm. The validation of this marker in nine resistant and seven susceptible genotypes has suggested its use in marker assisted breeding for developing MYMIV resistant genotypes in blackgram.     

Development of a SCAR marker linked with a MYMV resistance gene in mungbean (Vigna radiata L. Wilczek)

Yellow mosaic disease (YMD) caused by mungbean yellow mosaic virus (MYMV) is the most important disease of mungbean, causing great yield loss. The present investigation was carried out to study the inheritance and identify molecular markers linked with MYMV resistance gene by using F₁, F₂ and 167 F_2 : 8 recombinant inbred lines (RILs) developed from the cross ‘TM‐99‐37’ (resistant) × Mulmarada (susceptible). The F₁ was susceptible, F₂ segregated in 3S:1R phenotypic ratio and RILs segregated in 1S:1R ratio in the field screening indicating that the MYMV resistance gene is governed by a single recessive gene. Of the 140 RAPD primers, 45 primers showing polymorphism in parents were screened using bulked segregant analysis. Three primers amplified specific polymorphic fragments viz. OPB‐07_600, OPC‐06₁₇₅₀ and OPB‐12₈₂₀. The marker OPB‐07₆₀₀ was more closely linked (6.8 cM) with a MYMV resistance gene as compared to OPC‐06₁₇₅₀ (22.8 cM) and OPB‐12₈₂₀ (25.2 cM). The resistance‐specific fragment OPB‐07₆₀₀ was cloned, sequenced and converted into a sequence‐characterized amplified region (SCAR) marker and validated in twenty genotypes with different genetic backgrounds.     

Development of RAPD and ISSR derived SCAR markers linked to <Emphasis Type="Italic">Xca1Bo</Emphasis> gene conferring resistance to black rot disease in cauliflower (<Emphasis Type="Italic">Brassica oleracea</Emphasis> var. <Emphasis Type="Italic">botrytis</Emphasis> L.)

Black rot caused by Xanthomonas campestris pv. campestris (Xcc) (Pam.) is the most devastating disease of cauliflower (Brassica oleracea var. botrytis L.; 2n = 2x = 18), taking a heavy toll of the crop. In this study, a random amplified polymorphic DNA (RAPD) and inter simple sequence repeat (ISSR) derived sequence characterized amplified region (SCAR) markers linked to the black rot resistance locus Xca1bo were developed and evaluated as a screening tool for resistance. The RAPD marker OPO-04₈₃₃ and ISSR marker ISSR-11₆₃₅ were identified as closely linked at 1.6 cM distance to the black rot resistance locus Xca1bo. Both the markers OPO-04₈₃₃ and ISSR-11₆₃₅ were cloned, sequenced and converted into SCAR markers and validated in 17 cauliflower breeding lines having different genetic backgrounds. These SCAR markers (ScOPO-04₈₃₃ and ScPKPS-11₆₃₅) amplified common locus and showed 100% accuracy in differentiating resistant and susceptible plants of cauliflower breeding lines. The SCAR markers ScOPO-04₈₃₃ and ScPKPS-11₆₃₅ are the first genetic markers found to be linked to the black rot resistance locus Xca1bo in cauliflower. These markers will be very useful in black rot resistance marker assisted breeding.     

Effect of thidiazuron (TDZ) on in vitro regeneration of blackgram (Vigna mungo L.) embryonic axes

Regeneration has been achieved in blackgram (Vigna mungo) using thidiazuron (TDZ) in the culture medium. The explanted cotyledon with wounded embryonic axes produced the highest number (9.75–10.45) of healthy, elongated shoots when cultured on shoot bud regeneration medium (SRI) composed of 2 μM BAP, 2 μM KIN, 2 μM TDZ, and 0.5 μM NAA followed by multiple shoot regeneration (SRII) medium containing 2 μM BAP, 2 μM KIN, and multiple shoot elongation (SE) medium (0.5 μM of BAP + 0.5 μM of KIN). The presence of TDZ in combination with BAP and NAA in the SRI medium for one sub-culture cycle (10–14 days) significantly increases formation of multiple shoot buds per explant. Independent, healthy shoots obtained were selected for both in vitro rooting and grafting. Establishment of plantlets in the soil was highest (80–100%) in the case of in vitro rooted compared to grafted shoots (40%). The protocol appears to be competent to Agrobacterium-meditated transformation with ‘gus’ as a reporter gene. PCR analysis of the T₀ and T₁ progenies showed the presence and transmission of the transgene. We document here the regeneration and transformation of blackgram using cotyledons with wounded embryonic axes and the protocol appears to be suitable for genetic transformation of blackgram.     

Genetic relationship in Vigna mungo (L.) Hepper and V. radiata (L.) R. Wilczek based on morphological traits and SDS-PAGE

Thirty seven diverse genotypes of Vigna mungo and three of V. radiataresembling to V. mungo for seed characters were studied to determine the extent of genetic variation based on morphological characters. In addition, 4black seeded genotypes in each species and8 green seeded V. radiata genotypes were included for SDS-PAGE analysis. Seed proteins were analyzed through slab type SDS-PAGE. High variance was observed for plant height, days to flowering, days to maturity, number of branches/plant, number of pods/plant, pod length, seeds per pod,biomass yield/plant, grain yield/plant and harvest index (%) during 2 consecutive years. First four components of PCA with eigenvalues >1 contributed 78.7 and79.1% of the total variance amongst 40genotypes during 1998 and 1999. The populations with high PC₁ values were expected to be high yielding characterised by earlyness, high seed weight and harvest index, all traits strictly related to reproductive phase. Four clusters of genotypes were observed during both the years and genetic diversity was in association for both the years. Based on SDS-PAGE, specific bands were suggested to be used for identifying Vigna radiatafrom mixed germplasm with Vigna mungo. The SDS-PAGE proved to be a powerful tool for differentiating Vigna radiata and Vigna mungo, whereas a low level inter-specific genetic diversity was observed and no clear differentiation was observed both for agronomic characteristics and for geographical origin. This revised version was published online in July 2006 with corrections to the Cover Date.     

Development of SCAR markers linked to the Ns locus in potato

A random amplified polymorphic DNA marker OPG17₄₅₀ linked to the Ns gene that confers resistance of potato to potato virus S (PVS), was used to develop sequence‐characterized amplified region (SCAR) markers. After cloning and sequencing of OPG17₄₅₀ new polymerase chain reaction (PCR) primers were designed to generate dominant (SCG17₃₂₁) and codominant (SCG17₄₄₈) markers. For SCG17₄₄₈, polymorphism between susceptible and resistant genotypes was recovered after digestion of the marker with the restriction enzyme Muni. In addition to the band corresponding to ‘susceptible’ allele that does not contain the Muni cleavage site, two bands of approximately 251 bp and 197 bp were observed in the resistant genotypes. The usefulness of these SCAR markers was verified in diploid potatoes possessing the Ns locus from clone G‐LKS 678147/60, and in tetraploid potatoes derived from G‐LKS 678147/60 and from clone MPI 65118/3.     

Introgression of productivity and other desirable traits from ricebean (Vigna umbellata) into black gram (Vigna mungo)

Crosses were performed to introgress genes for productivity and other desirable traits from ricebean (Vigna umbellata) into black gram (Vigna mungo). Crossability was very poor in black gram × ricebean crosses, and only two to nine true hybrid plants were obtained. Plant fertility was very poor in initial generations, but was improved gradually from F₂ onwards. Twenty‐four uniform progenies, bulked in F₇, were evaluated for yield potential. The percentage increase/decrease in yield ranged from ?35.48 to 50.31 over the check cultivar (‘Mash338’, female parent). All the progenies were found resistant to Mungbean yellow mosaic virus, Cercospora leaf spot and Bacterial leaf spot diseases. Overall, it was found that desirable traits such as high pod number, seed weight, productivity and resistance to diseases have been introgressed successfully into black gram from ricebean. A derivative line, KUG114, recorded yield superiority of 39.45% over the check cultivar ‘Mash338’ on the average of 14 multilocation research trials. It was released under the name ‘Mash114’ for cultivation in the Punjab state.     

Identification and characterization of RAPD and SCAR markers linked to anthracnose resistance gene in sorghum [Sorghum bicolor (L.) Moench]

Anthracnose, one of the destructive foliar diseases of sorghum growing in warm humid regions, is incited by the fungus Colletotrichum graminicola.The inheritance of anthracnose resistance was studied using the parental cultivars of Sorghum bicolor (L.) Moench, HC 136 (susceptible to anthracnose) and G 73 (anthracnose resistant). The F₁ and F₂ plants were inoculated with the local isolates of C. graminicola cultures. The F₂ plants showed a segregation ratio of 3 (susceptible): 1(resistant) indicating that the locus for resistance to anthracnose in sorghum accession G 73 segregates as a recessive trait in a cross to susceptible cultivar HC 136. RAPD (random amplified polymorphic DNA) marker OPJ 01₁₄₃₇ was identified as marker closely linked to anthracnose resistance gene in sorghum by bulked segregant analysis of HC 136 × G73 derived recombinant inbred lines (RILs) of sorghum. A total of 84 random decamer primers were used to screen polymorphism among the parental genotypes. Among these, only 24 primers were polymorphic. On bulked segregant analysis, primer OPJ 01 amplified a 1437 bp fragment only in resistant parent G 73 and resistant bulk. The marker OPJ 01₁₄₃₇ was cloned and sequenced. The sequence of RAPD marker OPJ 01₁₄₃₇ was used to generate specific markers called sequence characterized amplified regions (SCARs). A pair of SCAR markers SCJ 01-1 and SCJ 01-2 was developed using Mac Vector program. SCAR amplification of resistant and susceptible parents along with their respective bulks and RILs confirmed that SCAR marker SCJ 01 is at the same loci as that of RAPD marker OPJ 01₁₄₃₇ and hence, is linked to anthracnose resistance gene. Resistant parent G 73 and resistant bulk amplified single specific band on PCR amplification using SCAR primer pairs. The RAPD marker OPJ 01₁₄₃₇ was mapped at a distance of 3.26 cM apart from the locus governing anthracnose resistance on the sorghum genetic map by the segregation analysis of the RILs. Using BLAST program, it was found that the marker showed 100 per cent alignment with the contig{_}3966 located on the longer arm of chromosome 8 of sorghum genome. Therefore, these identified RAPD and SCAR markers can be used in the resistance-breeding program of sorghum anthracnose by marker-assisted selection.An erratum to this article can be found at     

Identification of a molecular marker linked to an Agropyron elongatum-derived gene Lr19 for leaf rust resistance in wheat

The leaf rust resistance gene Lr19, transferred from Agropyron elongatum into wheat (Triticum aestivum L.) imparts resistance to all pathotypes of leaf rust (Puccinia recondita f.sp. tritici) in South‐east Asia. A segregating F₂ population from a cross between the leaf rust resistant parent ‘HW 2046’ carrying Lr19 and a susceptible parent ‘Agra Local’ was screened in the phytotron against a virulent pathotype 77‐5 of leaf rust with the objective of identifying the molecular markers linked to Lr19. The gene was first tagged with a randomly amplified polymorphic DNA (RAPD) marker S73₇₂₈. The RAPD marker linked to the gene Lr19 which mapped at 6.4 ± 0.035 cM distance, was converted to a sequence characterized amplified region (SCAR) marker. The SCAR marker (SCS73₇₁₉) was specific to Lr19 and was not amplified in the near‐isogenic lines (NILs) carrying other equally effective alien genes Lr9, Lr28 and Lr32 enabling breeders to pyramid Lr19 with these genes.     

Genetic analysis of gene‐specific resistance to mungbean yellow mosaic virus in mungbean (Vigna radiata)

Six intervarietal crosses involving two resistant and three susceptible genotypes of mungbean were attempted with the objectives to determine the mode of inheritance of gene‐specific Mungbean Yellow Mosaic Virus (MYMV) resistance. An infector row technique along with artificial inoculation was used for evaluating parents, F₁, F₂ and F₃ plants for MYMV resistance. Disease scoring for MYMV indicated that F₁s were highly susceptible as were the susceptible parents while resistant parent exhibited resistant reaction. The F₂ progeny segregated in the ratio of 9 S:3 MS:3 MR:1 R suggesting that the resistance was governed by digenic recessive genes (r_m1 and r_m2). When one gene (r_m1) was present in the homozygous recessive condition in different plants, it conferred moderately susceptible (MS) reaction, whereas when other gene (r_m2) was in homozygous condition, moderately resistant (MR) reaction was obvious. When both genes (r_m1 and r_m2) were present together in the homozygous recessive condition, resistant reaction (R) was observed. The F₂ segregation explained on the basis of phenotypic expression was further confirmed by F₃ segregation.     

Development of cleaved amplified polymorphic sequence (CAPS) markers linked to a green rice leafhopper resistance gene, Grh3(t)

The chromosomal location of the resistance gene for green rice leafhopper (GRLH), an injurious insect for rice, has been determined and RFLP markers closely linked to this gene have been identified. The susceptible japonica rice variety ‘Nipponbare’ was crossed with a resistant japonica rice line ‘Aichi42’, in which green rice leaf hopper resistance had been introduced from an indica variety ‘Rantaj‐emas2’, and the 100 F₂ plants obtained were used for linkage analysis. The green rice leafhopper resistance gene, Grh3(t), was mapped between RFLP markers C288B and C133A on chromosome 6 and co‐segregated with C81. Of the RFLP markers tightly linked to Grh3(t), C81 was converted to a SCAR marker and C133A to a cleaved amplified polymorphic sequence marker that could distinguish the heterozygous genotype to establish an effective marker‐aided selection system for the GRLH resistance gene.     

Identification, characterisation, and chromosome locations of rye and wheat specific ISSR and SCAR markers useful for breeding purposes

Rye (Secale cereale L. and S. strictum) offers potential to increase the genetic variability and to introduce desirable characters for wheat improvements. Cytogenetic techniques have been used to screen wheat lines containing rye chromatin. These techniques are not adequate since they are highly technical and time consuming. They are not suitable for breeding programs that require rapid screening of large numbers of genotypes. The main objective of this study was to develop and characterize ISSR and SCAR markers that can distinguish wheat from rye genome. Total DNA from wheat, rye, and triticale accessions from different provenances were amplified with ISSR primers in PCR assays. Three wheat-diagnostic sequences were identified. In addition three rye-diagnostic ISSR markers of which, one marker specifically diagnostic for Secale strictum were characterized. Pairs of primers flanking these specific sequences were designed to produce SCAR markers. Two SCAR markers were rye genome-specific. One SCAR was present in all the seven rye chromosome, and another was specific to rye chromosomes two, three, four, and seven. These newly developed ISSR and SCAR markers should be useful to wheat breeders screening genotypes that may contain rye chromatins.     

Identification of DNA markers linked to an induced mutated gene conferring resistance to powdery mildew in pea (<Emphasis Type="Italic">Pisum sativum</Emphasis> L.)

We have recently induced two powdery mildew (Erysiphe pisi Syd) resistant mutants in Pisum sativum L. via ethylnitrosourea (ENU) mutagenesis. Both mutations (er1mut1 and er1mut2) affected the same locus er1 that determines most of the identified natural sources of powdery mildew resistance (PMR) in this crop. The mutated gene er1mut2 was mapped to a linkage group of 16 DNA markers combining three main strategies: near isogenic lines (NILs) analysis, bulked segregant analysis and genetic mapping of randomly identified polymorphic markers, together with three DNA-markers techniques: ISSR, RAPDs and AFLPs. Markers located closer to the PMR locus, OPO06_1100y (0.5 cM), OPT06₄₈₀ (3.3 cM) and AGG/CAA₁₂₅ (5.5 cM), were cloned and converted into SCAR markers. Markers AH1R₈₅₀ and AHR_920y were found to be allelic and converted into the co-dominant marker ScAH1 (16.3 cM). Two previously known DNA markers, ScOPE16₁₆₀₀ and A5_420y, were mapped at 9.6 and 23.0 cM from the PMR locus, respectively. The novel markers identified in this study are currently being transferred to a new F2 mapping population derived from a cross between the induced PMR mutant line F(er1mut2) and a more genetically distant susceptible line of Pisum sativum var. arvense.     

Molecular mapping of black rot resistance locus Xca1bo on chromosome 3 in Indian cauliflower (Brassica oleracea var. botrytis L.)

Black rot is the most devastating disease of cauliflower worldwide causing severe damage to crop. The identification of markers linked to loci that control resistance can facilitate selection of plants for breeding programmes. In the present investigation, F₂ population derived from a cross between ‘Pusa Himjyoti’, a susceptible genotype, and ‘BR‐161’, a resistant genotype, was phenotyped by artificial inoculation using Xcc race 1. Segregation analysis of F₂ progeny indicated that a single dominant locus governed resistance to Xcc race 1 in ‘BR‐161’. Bulk segregant analysis in resistant and susceptible bulks of F₂ progeny revealed seven differentiating polymorphic markers (three RAPD, two ISSR and two SSR) of 102 markers screened. Subsequently, these markers were used to genotype the entire F₂ population, and a genetic linkage map covering 74.7 cM distance was developed. The major locus Xca1bo was mapped in 1.6‐cM interval flanked by the markers RAPD 04₈₃₃ and ISSR 11₆₃₅. The Xca1bo locus was located on chromosome 3. The linked markers will be useful for marker‐assisted resistance breeding in cauliflower.     

Genetic diversity in mung bean germplasm revealed by RAPD markers

Knowledge of the genetic relationships among landraces is useful to gene bank managers because it permits a better organization of the crop's gene pool management, more efficient sampling of the available germplasm resources and better access to useful genetic variation for breeders. Genetic diversity of 19 landraces of the cultivated mung bean, Vigna radiate, and three weedy and wild relatives including Vigna mungo, Vigna luteola and Vigna radiate var. sublobata, was investigated at the DNA level with the random amplified polymorphic DNA (RAPD) procedure. Sixty random decamer primers were employed in amplification reactions; 28 of these were informative and yielded 246 bands, of which 229 were polymorphic with a mean of 8.2 bands per primer. A genetic distance matrix based on Nei and Li coefficient was converted to a dendrogram and a two-dimensional plot using multidimensional scaling (MDS). The accessions studied were separated into three main clusters, which included V. radiate landraces, V. mungo and V. luteola, respectively. The variation of this cluster supports the view that the genetic distance of V. mungo and V. luteola varies considerably from the accession VO2955 (V. radiata). The multidimensional scaling plot confirmed that V. mungo, V. luteola and most of the accessions of V. radiata formed distinct clusters with no overlap, and two mung bean accessions (PI177493 and VO4134–1 from Turkey and India, respectively) were genetically distant from other V. radiata landraces. V. radiata and V. mungo are positioned in separate botanical species and V. radiata var. sublobata is classified within other V. radiata landraces. Based on the limited range of accessions tested, the approach holds promise for the classification of mung bean germplasm, identification of mung bean landraces and applications of molecular markers to mung bean breeding.     

Identification of molecular markers associated with oleic and linolenic acid in spring oilseed rape (Brassica napus)

The quality of the oil derived from oilseed rape is determined by its fatty acid composition. Breeding oilseed rape for enhanced oil quality includes the development of cultivars with high oleic and low linolenic acid. Random amplified polymorphic DNA (RAPD) and intersimple sequence repeat (ISSR) techniques were investigated for the development of molecular markers for genes controlling oleic and/or linolenic acid. Markers that were identified were converted to sequence characterized amplified region (SCAR) markers for use in breeding. Molecular markers associated with these two fatty acids were identified in a doubled haploid population derived from a cross between the oilseed rape lines TO99‐5318‐20, very high oleic (>79%) and very low linolenic acid (<2%) × DH12075, high oleic (68%) and higher linolenic acid (>7%). Eight RAPD markers were associated with oleic and linolenic acid contents. The RAPD marker UBC 2₈₃₀ accounted for 43% and 13% of the genetic variation for oleic and linolenic acid levels, respectively. The RAPD marker UBC 153₅₅₀ accounted for 19% of the genetic variation for linolenic acid. The UBC 2₈₃₀ fragment was converted to a SCAR marker. The markers identified in this study should be useful tools for the early generation selection of high oleic and low linolenic acid genotypes in oilseed rape breeding programmes.     

An extended random primer amplified region (ERPAR) marker linked to a dominant male sterility gene in cabbage (Brassica oleracea var. capitata)

Similar to SCAR, an extended random primer amplified region (ERPAR) marker is a PCR amplified genomic DNA fragment at a single genetically defined locus. However, ERPAR uses specific primer pairs derived from RAPD primers by adding bases sequentially to their 3′-ends. As an example, an ERPAR marker was derived from a RAPD marker (OT11₉₀₀) linked to a dominant male sterility gene in cabbage (Brassica oleracea var. capitata). After two cycles of base adding and primer pair screening, a primer pair (5′-TTCCCCGCGACT-3′and 5′-TTCCCCGCGAGA-3′) amplified a single intense band with the same size as OT11₉₀₀. The identity of the new marker and OT11₉₀₀ was verified by segregation analysis. The new marker amplified by this extended primer pair was named as EPT11₉₀₀. The development of ERPAR exploits the importance of 3′-end bases of primers in PCR ERPAR shares advantages of SCAR, but eliminates the need for cloning and sequencing. It is a fast and universal way of converting RAPD markers into stable markers. This revised version was published online in July 2006 with corrections to the Cover Date.     

RAPD and SCAR markers for resistance to acochyta blight in lentil

Resistance to ascochyta blight of lentil (Lens culinaris Medikus),caused by the fungus Ascochyta lentis, is determined by a single recessive gene, ral ₂, in the lentil cultivar Indian head. Sixty F₂ individuals from a cross between Eston (susceptible) and Indian head (resistant) lentil were analyzed for the presence of random amplified polymorphic DNA (RAPD) markers linked to the ral ₂gene, using bulked segregant analysis (BSA). Out of 800 decanucleotide primers screened, two produced polymorphic markers that co-segregated with the resistance locus. These two RAPD markers, UBC227₁₂₉₀and OPD-10₈₇₀, flanked and were linked in repulsion phase to the gene ral ₂ at 12 cm and 16 cm, respectively. The RAPD fragments were converted to SCAR markers. The SCAR marker developed from UBC227₁₂₉₀ could not detect any polymorphism between the two parents or in the F₂. The SCAR marker developed from OPD-10₈₇₀ retained its polymorphism. The polymorphic RAPD marker UBC227₁₂₉₀ and the SCAR marker developed from OPD-10₈₇₀ can be used together in a marker assisted selection program for ascochyta blight resistance in lentil. This revised version was published online in July 2006 with corrections to the Cover Date.