A genetic map of cucumber composed of RAPDs, RFLPs, AFLPs, and loci conditioning resistance to papaya ringspot and zucchini yellow mosaic viruses

Genome ◽  
2000 ◽  
Vol 43 (6) ◽  
pp. 1003-1010 ◽  
Author(s):  
Young Hoon Park ◽  
Suat Sensoy ◽  
Crispin Wye ◽  
Rudie Antonise ◽  
Johan Peleman ◽  
...  

The watermelon strain of papaya ringspot virus (PRSV-W) and zucchini yellow mosaic virus (ZYMV) are potyviruses that cause significant disease losses in cucumber. Resistances have been identified primarily in exotic germplasm that require transfer to elite cultivated backgrounds. To select more efficiently for virus resistances, we identified molecular markers tightly linked to PRSV-W and ZYMV resistances in cucumber. We generated F6 recombinant inbred lines (RILs) from a cross between Cucumis sativus L. 'Straight 8' and a line from 'Taichung Mou Gua', TMG1 (susceptible and resistant, respectively, to both viruses), and studied the segregations of amplified fragment length polymorphism (AFLP) markers, randomly amplified polymorphic DNAs (RAPDs), restriction fragment length polymorphisms (RFLPs), and resistances to PRSV-W and ZYMV. A 353-point map of cucumber was generated, delineating 12 linkage groups at LOD 3.5. Linkage arrangements among RFLPs were consistent with previously published maps; however linkages among RAPDs in our map did not agree with a previously published map. Resistances to PRSV-W and ZYMV were tightly linked (2.2 cM) and mapped to the end of one linkage group. One AFLP cosegregated with resistance to ZYMV.Key words: amplified fragment length polymorphism, randomly amplified polymorphic DNA, restriction fragment length polymorphism, virus resistance.

1999 ◽  
Vol 45 (9) ◽  
pp. 754-763 ◽  
Author(s):  
S Restrepo ◽  
T L Valle ◽  
M C Duque ◽  
V Verdier

Xanthomonas axonopodis pv.manihotis (Xam) causes bacterial blight, a major disease of cassava, which is a starchy root crop that feeds about 500 million people throughout the world. To better select resistant cassava germplasm, we examined the population structure of Xam in Brazil, Latin America's largest producer of cassava, and a major center of diversity for the crop. The 79 strains collected between 1941 and 1996 from three edaphoclimatic zones were analyzed by restriction fragment length polymorphism (RFLP), using a probe linked to a Xam pathogenicity gene (pthB). Thirty-eight haplotypes were identified, and geographical differentiation for the Xam strains was demonstrated. Strains from subtropical zone (ECZ 6) showed high genetic diversity in most of the sites from which they were collected. They also showed migration from site to site. RFLP and amplified fragment length polymorphism (AFLP) analyses were carried out on 37 Xam strains and compared; the AFLP assays were performed using eight primer combinations. A multiple correspondence analysis, used to assess genetic relatedness among strains and estimate genetic diversity, indicated that the Brazilian Xam population showed high diversity. No correlation was found between AFLP and RFLP data, but the two techniques provided complementary information on the genetic diversity of Xam. Most strains were highly aggressive on a susceptible cultivar. The genetic analysis presented here contributes to a better understanding of the Xam population structure in Brazil and will help select strains of the pathogen for screening cassava germplasm resistant to the disease.Key words: cassava bacterial blight, resistance, genetic diversity, molecular characterization.


Genome ◽  
2001 ◽  
Vol 44 (2) ◽  
pp. 213-221 ◽  
Author(s):  
Melaku Ayele Gedil ◽  
Crispin Wye ◽  
Simon Berry ◽  
Bart Segers ◽  
Johan Peleman ◽  
...  

Restriction fragment length polymorphism (RFLP) maps have been constructed for cultivated sunflower (Helianthus annuus L.) using three independent sets of RFLP probes. The aim of this research was to integrate RFLP markers from two sets with RFLP markers for resistance gene candidate (RGC) and amplified fragment length polymorphism (AFLP) markers. Genomic DNA samples of HA370 and HA372, the parents of the F2 population used to build the map, were screened for AFLPs using 42 primer combinations and RFLPs using 136 cDNA probes (RFLP analyses were performed on DNA digested with EcoRI, HindIII, EcoRV, or DraI). The AFLP primers produced 446 polymorphic and 1101 monomorphic bands between HA370 and HA372. The integrated map was built by genotyping 296 AFLP and 104 RFLP markers on 180 HA370 × HA372 F2 progeny (the AFLP marker assays were performed using 18 primer combinations). The HA370 × HA372 map comprised 17 linkage groups, presumably corresponding to the 17 haploid chromosomes of sunflower, had a mean density of 3.3 cM, and was 1326 cM long. Six RGC RFLP loci were polymorphic and mapped to three linkage groups (LG8, LG13, and LG15). AFLP markers were densely clustered on several linkage groups, and presumably reside in centromeric regions where recombination is reduced and the ratio of genetic to physical distance is low. Strategies for targeting markers to euchromatic DNA need to be tested in sunflower. The HA370 × HA372 map integrated 14 of 17 linkage groups from two independent RFLP maps. Three linkage groups were devoid of RFLP markers from one of the two maps.Key words: amplified fragment length polymorphism (AFLP), restriction fragment length polymorphism (RFLP), Helianthus, sunflower, genetic map.


Genome ◽  
1997 ◽  
Vol 40 (2) ◽  
pp. 242-248 ◽  
Author(s):  
I. Paran ◽  
I. Goldman ◽  
D. Zamir

Quantitative trait loci (QTLs) influencing morphological traits were identified by restriction fragment length polymorphism (RFLP) analysis in a population of recombinant inbred lines (RILs) derived from a cross of the cultivated tomato Lycopersicon esculentum with a related wild species, Lycopersicon cheesmanii. One hundred and thirty-two RFLP loci spaced throughout the tomato genome were used as DNA probes on genomic DNA from 97 RIL families. Morphological traits, including plant height, plant fresh mass, number of branches, number of nodes, first flower-bearing node, and leaf length, were evaluated in two controlled environment trials in 1992 and 1993. QTLs were detected via regression analyses at multiple marker loci for each morphological trait. A total of 41 markers were significantly associated with the traits examined. Large additive effects were measured at many of these loci. QTLs for multiple traits were detected on chromosomes 3 (TG74) and 4 (CT188), suggesting the possible association of these chromosome segments with genes controlling growth and development in tomato. These chromosomal regions were also associated with multiple morphological traits in a L. esculentum × Lycopersicon pennellii cross. A total of 13% of the QTLs identified for traits common to both studies occupied similar map positions.Key words: Lycopersicon, quantitative trait, restriction fragment length polymorphism.


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