The inheritance of fertility restoration in male-sterile wheat carrying cytoplasm derived from Triticum timopheevi

Summary The inheritance of the restoration of fertility in material carrying the cytoplasm of Triticum timopheevi was studied in F₂, F₃ and F₄ generations. In the material used the segregation of restoration was shown to fit the hypothesis of three major, dominant, partially dominant or additive genes each of which made a different contribution to restoration but which acted cumulatively to produce the phenotypic expression observed.From the material it was possible to extract homozygous lines carrying known combinations of these three genes which can be used as tester lines to investigate the inheritance of genes for restoration derived from other sources.     

Cytogenetics of inherited partial sterility in three generations of the large milkweed bug as related to holokinetic chromosomes

AdultOncopeltus fasciatus males were irradiated with 9000 R of X-rays, and crossed to untreated females. Fertility was reduced to 4.1%. F₁ males and F₂ and F₃ males and females were outcrossed to untreated partners. All F₁ males were partially or totally sterile and a significant number of F₂ and F₃ males and females had reduced fertility. The fertility of each generation was higher than the preceding one, even though the progeny studied in the 3rd generation were selected mostly from low-fertility lines. Cytogenetic studies showed that complex chromosome rearrangements and fragments were transmitted to each generation and were severe enough to account for reduced fertility. — The transmission of complex chromosome rearrangements and fragments for 3 generations of outcrossing correlates with the persistence of sterility in this species possessing holokinetic chromosomes. — Over half the inviable embryos derived from irradiated sperm from P₁ males died in the early stages of development. The inviable embryos produced in later generations died in much later stages of development. — A stable rearrangement of a Y-chromosome fragment translocated to an autosome was isolated from a single F₁ male. This rearrangement was transmitted to all F₂ and F₃ sons. Fertility of the males of this line was reduced to about 75–80%.Supported in part by AEC Contract No. AT(49-7)3028.     

Basic studies on hybrid wheat breeding

Summary The nuclei of 12 common wheats (genome constitution AABBDD) were placed into the cytoplasms of Aegilops kotschyi and Ae. variabilis (both C^uC^uS^vS^v) by repeated backcrosses. Using these nucleus-cytoplasm hybrids, male sterility-fertility restoration relationship was investigated. Male sterility was expressed by these cytoplasms only in Slm, Splt and Mch. The other nine common wheat nuclei gave normal fertility against these cytoplasms. These cytoplasms were compared with the Triticum timopheevi cytoplasm that is now widely used in the hybrid wheat breeding program in order to investigate their effects on important agronomic traits of the 12 common wheats: The kotschyi and variabilis cytoplasms were as good as the timopheevi cytoplasm in this respect.The F₁ hybrid between (kotschyi)- or (variabilis)-Splt and CS showed normal fertility. Segregation of the fertiles and steriles in their F₂ generations followed the simple Mendelian fashion, i.e., 3 fertile1 sterile. Thus, the fertility restoration in this case is mainly controlled by a single dominant gene which will be designated as Rfv1. To determine its location, ditelo-lBS and -lBL of CS were crossed as male parents to male sterile (kotschyi)- and (variabilis)-Splt. The F₁ hybrids between the male sterile Spit's and CS ditelo-lBS became male fertile, while those between the male sterile Spit's and CS ditelo-lBL became completely male sterile. Thus, the location of the gene Rfv1 has been determined to be on the short arm of chromosome lB of CS. Furthermore, a close relationship between the fertility-restoring genes and the nucleolus organizer region was pointed out.Finally, the schemes of breeding the male sterile lines of a cultivar with these cytoplasms, and its maintainer line were formulated. The following two points were considered as the advantages of the present male sterility-fertility restoration system over that using the timopheevi cytoplasm in breeding hybrid wheat: (1) easier fertility restoration in F₁ hybrids, and (2) no need of breeding the restorer line.This work was supported by a Grand-in-Aid from the Ministry of Education, No. 386002. Contribution from the Laboratory of Genetics, Faculty of Agriculture, Kyoto University, Japan, No. 420.     

Additive transgene expression and genetic introgression in multiple green-fluorescent protein transgenic crop × weed hybrid generations

The level of transgene expression in crop × weed hybrids and the degree to which crop-specific genes are integrated into hybrid populations are important factors in assessing the potential ecological and agricultural risks of gene flow associated with genetic engineering. The average transgene zygosity and genetic structure of transgenic hybrid populations change with the progression of generations, and the green fluorescent protein (GFP) transgene is an ideal marker to quantify transgene expression in advancing populations. The homozygous T₁ single-locus insert GFP/Bacillus thuringiensis (Bt) transgenic canola (Brassica napus, cv Westar) with two copies of the transgene fluoresced twice as much as hemizygous individuals with only one copy of the transgene. These data indicate that the expression of the GFP gene was additive, and fluorescence could be used to determine zygosity status. Several hybrid generations (BC₁F₁, BC₂F₁) were produced by backcrossing various GFP/Bt transgenic canola (B. napus, cv Westar) and birdseed rape (Brassica rapa) hybrid generations onto B. rapa. Intercrossed generations (BC₂F₂ Bulk) were generated by crossing BC₂F₁ individuals in the presence of a pollinating insect (Musca domestica L.). The ploidy of plants in the BC₂F₂ Bulk hybrid generation was identical to the weedy parental species, B. rapa. AFLP analysis was used to quantify the degree of B. napus introgression into multiple backcross hybrid generations with B. rapa. The F₁ hybrid generations contained 95–97% of the B. napus-specific AFLP markers, and each successive backcross generation demonstrated a reduction of markers resulting in the 15–29% presence in the BC₂F₂ Bulk population. Average fluorescence of each successive hybrid generation was analyzed, and homozygous canola lines and hybrid populations that contained individuals homozygous for GFP (BC₂F₂ Bulk) demonstrated significantly higher fluorescence than hemizygous hybrid generations (F₁, BC₁F₁ and BC₂F₁). These data demonstrate that the formation of homozygous individuals within hybrid populations increases the average level of transgene expression as generations progress. This phenomenon must be considered in the development of risk-management strategies.Communicated by J. Dvorak     

Influence of Low-Intensity Electromagnetic Field on Some Biological Parameters of Freshwater Crustaceans <Emphasis Type="Italic">Daphnia magna</Emphasis> Straus

We have studied the effects of a low-intensity electromagnetic field (EMF) with a frequency of 30 MHz in continuous-wave and amplitude-modulation modes on Daphnia magna in a laboratory culture. The exposure range is from 10 to 10000 s. We examine the parental generation (irradiated) and three subsequent (F₁–F₃) generations (nonirradiated). It is found that irradiation does not affect the total fertility of any specimen in four generations (P–F₃), except for continuous EMF exposure for 10000 s, which increases the total fertility in generations F₂ and F₃ by 23 and 43%, respectively. Electromagnetic radiation has a significant impact on offspring quality and causes fetal abnormalities in the offspring of all generations.     

Genetic analyses and mapping of a new thermo-sensitive genic male sterile gene in maize

The present study describes a novel thermo-sensitive genic male sterile (TGMS) line, Qiong68ms. To analyse the mode of fertility inheritance and tag the TGMS gene, a set of F₂, BC₁ and F_2:3 populations derived from a cross between Qiong68ms and K12 were evaluated for a period of 2 years. Classical genetic analyses and QTL mapping using the mean restoration percentage of the F_2:3 populations revealed that the fertility of Qiong68ms was likely to be governed by a single recessive gene, which was named tms3; the tms3 gene was mapped to a location between SSR markers umc2129 and umc1041, at a distance of 3.7 cM form umc2129 and 1.5 cM form umc1041. The molecular markers tightly linked with tms3 gene will aid in the transfer of the TGMS gene to various background inbred lines using the MAS method.     

Persistence of male sterility in strains issued from hybrids between two sibling species:Drosophila simulans andD. mauritiana

The cross between two sibling species,D. simulans andD. mauritiana, produced F₁ fertile females and sterile males. Backcrosses of these females to parental males resulted in the production of a small proportion of fertile males. From this second generation, four lines were propagated by mass mating and the frequency of fertile males was determined up to the 20th generation. In all cases, a linear increase of the proportion of fertile males was observed between the 2d and 8th generations and then the proportion remained stable at a level of 91%. From these observations several conclusions seem possible. (1) Male fertility was determined by several genes existing under different allelic conditions in the two sibling species; (2) the progressive restoration of male fertility was due to a normalizing selection which favored the homozygotes against the heterozygotes; (3) the persistence of a small frequency of sterile males after the 8th generation was the consequence of a balancing selection favoring the heterozygous condition (possibly in the females); (4) introgression of genes from one species into the genome of another species appeared capable of increasing the genetic heterogeneity of the population for a long time.     

Genetic analysis and molecular mapping of a new fertility restorer gene Rf8 for Triticum timopheevi cytoplasm in wheat (Triticum aestivum L.) using SSR markers

A study on mode of inheritance and mapping of fertility restorer (Rf) gene(s) using simple sequence repeat (SSR) markers was conducted in a cross of male sterile line 2041A having Triticum timopheevi cytoplasm and a restorer line PWR4099 of common wheat (Triticum aestivum L.). The F₁ hybrid was completely fertile indicating that fertility restoration is a dominant trait. Based on the pollen fertility and seed set of bagged spikes in F₂ generation, the individual plants were classified into fertile and sterile groups. Out of 120 F₂ plants, 97 were fertile and 23 sterile (based on pollen fertility) while 98 plants set ≥5 seeds/spike and 22 produced ≤4 or no seed. The observed frequency fits well into Mendelian ratio of 3 fertile: 1 sterile with χ² value of 2.84 for pollen fertility and 2.17 for seed setting indicating that the fertility restoration is governed by a single dominant gene in PWR4099. The three linked SSR markers, Xwmc503, Xgwm296 and Xwmc112 located on the chromosome 2DS were placed at a distance of 3.3, 5.8 and 6.7 cM, respectively, from the Rf gene. Since, no known Rf gene is located on the chromosome arm 2DS, the Rf gene in PWR4099 is a new gene and proposed as Rf8. The closest SSR marker, Xwmc503, linked to the Rf8 was validated in a set of Rf, maintainer and cytoplasmic male sterile lines. The closely linked SSR marker Xwmc503 may be used in marker-assisted backcross breeding facilitating the transfer of fertility restoration gene Rf8 into elite backgrounds with ease.     

Cytogenetic study of an interspecific cross of Nicotiana debneyi X N. umbratica

Summary Interspecific F₁ hybrids of Nicotiana debneyi Domin (2n=48) and N. umbratica Burbidge (2n=46), both belonging to the section Suaveolentes, showed a high degree of meiotic chromosome pairing. Two of the five F₂ plants obtained exhibited chromosome mosaicism. The first colchiploid generation (C₁) had the expected chromosome number of 2n=94 while C₂ showed 2n=88, a loss of three pairs of chromosomes. This same chromosome number continued in further colchiploid generations, followed up to C₅, except for a few plants in C₃ which showed chromosome mosaicism. The F₁ phenotype was stable through C₁ to C₅ and fertility was normal in colchiploids through all generations in spite of the loss of three pairs of chromosomes and chromosome mosaicism. This stability and fertility apparently reflect the tolerance of the genomes to the genetic adjustment of chromosome complements which is believed to be associated with the originally polyploid nature of the parental species and the chromosome doubling brought about in the amphidiploids.     

Molecular mapping of the fertility restorer gene for ms-CW-type cytoplasmic male sterility of rice

Cytoplasmic male sterility (CMS) of rice (Oryza sativa L.) was first reported using the cytoplasm of a Chinese wild rice, Oryza rufipogon Griff. strain W1. However, it was not possible to characterize this ms-CW-type CMS in more detail until a restorer line had been developed due to the lack of restorer genes among cultivars thus far tested. The breeding of a restorer line (W1-R) was eventually achieved by transferring the restorer gene(s) of W1 to a cultivar. We report here the characterization of the ms-CW pollen grains and mapping of the restorer gene for ms-CW-type CMS. Pollen grains of the male-sterile plants appeared to be normal and viable based on the fluorochromatic reaction test, but they did not germinate on normal stigmas. The 1:1 segregation of fertile and sterile plants in a BC₁F₁ population from a cross between W1-R and a maintainer line demonstrated that fertility restoration is controlled by a single gene. The fertile seed set of all the F₂ plants examined indicated that the fertility restoration functions gametophytically. We designated the fertility restorer gene Rfcw. Using cleaved amplified polymorphic sequence (CAPS) and simple sequence repeat (SSR) markers, we localized Rfcw to chromosome 4 with a genetic distance of 0.6 cM from the nearest SSR marker.     

Molecular mapping of the rf1 gene for pollen fertility restoration in sorghum (Sorghum bicolor L.)

We report the molecular mapping of a gene for pollen fertility in A1 (milo) type cytoplasm of sorghum using AFLP and SSR marker analysis. DNA from an F₂ population comprised of 84 individuals was screened with AFLP genetic markers to detect polymorphic DNAs linked to fertility restoration. Fifteen AFLP markers were linked to fertility restoration from the initial screening with 49 unique AFLP primer combinations (+3/+3 selective bases). As many of these AFLP markers had been previously mapped to a high-density genetic map of sorghum, the target gene (rf1) could be mapped to linkage group H. Confirmation of the map location of rf1 was obtained by demonstrating that additional linkage group-H markers (SSR, STS, AFLP) were linked to fertility restoration. The closest marker, AFLP Xtxa2582, mapped within 2.4 cM of the target loci while two SSRs, Xtxp18 and Xtxp250, flanked the rf1 locus at 12 cM and 10.8 cM, respectively. The availability of molecular markers will facilitate the selection of pollen fertility restoration in sorghum inbred-line development and provide the foundation for map-based gene isolation. Received: 22 August 2000 / Accepted: 18 October 2000     

Molecular mapping and candidate gene identification of the Rf2 gene for pollen fertility restoration in sorghum [Sorghum bicolor (L.) Moench]

The A1 cytoplasmic–nuclear male sterility system in sorghum is used almost exclusively for the production of commercial hybrid seed and thus, the dominant genes that restore male fertility in F₁ hybrids are of critical importance to commercial seed production. The genetics of fertility restoration in sorghum can appear complex, being controlled by at least two major genes with additional modifiers and additional gene–environment interaction. To elucidate the molecular processes controlling fertility restoration and to develop a marker screening system for this important trait, two sorghum recombinant inbred line populations were created by crossing a restorer and a non-restoring inbred line, with fertility phenotypes evaluated in hybrid combination with three unique cytoplasmic male sterile lines. In both populations, a single major gene segregated for restoration which was localized to chromosome SBI-02 at approximately 0.5 cM from microsatellite marker, Xtxp304. In the two populations we observed that approximately 85 and 87% of the phenotypic variation in seed set was associated with the major Rf gene on SBI-02. Some evidence for modifier genes was also observed since a continuum of partial restored fertility was exhibited by lines in both RIL populations. With the prior report (Klein et al. in Theor Appl Genet 111:994–1012, 2005) of the cloning of the major fertility restoration gene Rf1 in sorghum, the major fertility restorer locus identified in this study was designated Rf2. A fine-mapping population was used to resolve the Rf2 locus to a 236,219-bp region of chromosome SBI-02, which spanned ~31 predicted open reading frames including a pentatricopeptide repeat (PPR) gene family member. The PPR gene displayed high homology with rice Rf1. Progress towards the development of a marker-assisted screen for fertility restoration is discussed.     

Abnormally High Nourishment During Sensitive Periods Results in Body Weight Changes Across Generations

Objective : This study asked whether a brief period of over-nutrition during a developmentally sensitive time could impact the individual's adult weight and that of succeeding generations. Research Methods and Procedures : Female rat pups (F₁ generation) were randomly assigned to 1 of 3 groups: (1) a control group that was naturally reared by mothers; (2) another control group implanted with chronic gastric fistulas on postnatal day 4 and fed enough formula to match the growth of the mother-reared group; and (3) an experimental group gastrostomized and infused from day 8 through day 16 with a greater quantity of food than gastrostomy-reared controls (OF). On postnatal day 16, both gastrostomy-reared groups were returned to normal litters. Adult F₁ females from overfed and mother-reared groups were bred with normal males to yield an F₂ generation. F₂ adult females were bred to normal males to produce an F₃ generation. Results : When adult, the F₁ experimental group was heavier than control groups. F₂ adults from OF mothers were smaller than those from the control group. F₃ animals from OF grandmothers were heavier at weaning than F3 descendants from mother-reared animals. Discussion : Excess nourishment during a developmentally sensitive period changed the metabolic phenotype of one generation so dramatically that the gestational development and subsequent phenotype of two succeeding generations were also changed. The experiment models fetal effects of gestational diabetes in humans and may help to elucidate how, independent of genetic anomalies, secular changes can be detected across generations.     

QTL involved in the partial restoration of male fertility of C-type cytoplasmic male sterility in maize

Partial restoration of male fertility limits the use of C-type cytoplasmic male sterility (C-CMS) for the production of hybrid seeds in maize. Nevertheless, the genetic basis of the trait is still unknown. Therefore, the aim to this study was to identify genomic regions that govern partial restoration by means of a QTL analysis carried out in an F₂ population (n = 180). This population was derived from the Corn Belt inbred lines B37C and K55. F₂BC₁ progenies were phenotyped at three locations in Switzerland. Male fertility was rated according to the quality and number of anthers as well as the anthesis-silking interval. A weak effect of environment on the expression of partial restoration was reflected by high heritabilities of all fertility-related traits. Partial restoration was inherited like an oligogenic trait. Three major QTL regions were found consistently across environments in the chromosomal bins 2.09, 3.06 and 7.03. Therefore, a marker-assisted counter-selection of partial restoration is promising. Minor QTL regions were found on chromosomes 3, 4, 5, 6 and 8. A combination of partial restorer alleles at different QTL can lead to full restoration of fertility. The maternal parent was clearly involved in the partial restoration, because the restorer alleles at QTL in bins 2.09, 6.04 and 7.03 originated from B37. The three major QTL regions collocated with other restorer genes of maize, a phenomenon, which seems to be typical for restorer genes. Therefore, a study of the clusters of restorer genes in maize could lead to a better understanding of their evolution and function. In this respect, the long arm of chromosome 2 is particularly interesting, because it harbors restorer genes for the three major CMS systems (C, T and S) of maize.     

Cytoplasmic male sterility and nuclear restorer genes in a natural population of Beta maritima: genetical and molecular aspects

Summary One natural population (F₀ generation) of Beta maritima situated on the French Atlantic coast has been analysed. It was composed of 62% female, 30% hermaphrodite and 8% intermediate plants. The analysis of half-sib progeny (F₁ generation) obtained from in situ open pollination demonstrates the cytoplasmic determination of male sterility in Beta maritima and the restoration of fertility by nuclear genes. The mitochondrial DNA (mtDNA) and the chloroplast DNA (ctDNA) of sixteen F₁ plants, extracted from offspring of the three sexual phenotypes, were analysed using the restriction enzymes Sal I and Bam HI, respectively. Two cytoplasmic lines with their own peculiar genetic characteristics were distinguished using the restriction enzyme patterns of mtDNA: (i) the S cytoplasmic line was found in segregating progeny of two F₀ plants; all three phenotypes were produced (that is, progeny including hermaphrodite, female and intermediate plants); (ii) the N cytoplasmic line was found in the progeny of one F₀ hermaphrodite plant; this produced only hermaphrodites. Thus, segregating and non-segregating hermaphrodite F₀ plants can be distinguished. The nuclear genes maintaining sterility or restoring fertility are expressed in line S. At the same time the analysis of Beta vulgaris material has been carried out at the molecular level: N cytoplasmic lines of B. vulgaris and B. maritima differed only by 3 fragments of mtDNA; but the S cytoplasmic line of B. maritima was very different from Owen's cytoplasmic male sterile line of B. vulgaris. No variation in the ctDNA pattern was detected within and between the two taxa.     

The inheritance of resistance to Rhynchosporium secalis in some European spring barley cultivars

The inheritance of partial resistance to Rhynchosporium secalis, which appears to be race non-specific, was studied in a diverse range of European spring barley cultivars. Data from the F₂ generation of a 6 × 6 diallel cross and the F₃ generation of three crosses selected from this diallel set suggested that resistance was complex in inheritance, the results being incompatible with any hypothesis involving less than four genes. The F₂ studies indicated that both dominant and recessive genes were active in conferring resistance, and that there were significant additive gene effects. Transgressive segregation occurred in all cross combinations in the F₃ material. Consequently the alleles conferring resistance were not completely concentrated in the most resistant cultivar studied (cv. Proctor). Heritability estimates obtained from F₂ and F₃ material suggested that field selection was of limited reliability, even when spreader drills were incorporated amongst the segregates. Single-plant selection (in F₂) was considered to be of little value, and the results of F_a head-row tests would require confirmation by replicated tests in subsequent generations.     

Genetics and molecular mapping of a male fertility restoration locus (Rfg1) in rye (Secale cereale L.)

 A gene determining the restoration of cytoplasmic genic male sterility (CMS) caused by the Gülzow (G)-type cytoplasm was mapped by analyzing an F₂ and F₃ population comprising 140 and 133 individual plants, respectively. The target gene, designated Rfg1, was mapped on chromosome 4RL distally to three RFLP (Xpsr119, Xpsr167, Xpsr899) and four RAPD (XP01, XAP05, XR11, XS10) loci. Xpsr167 and Xpsr899 are known to be located on the segment of chromosome 4RL which was ancestrally translocated and is homoeologous to the distal end of other Triticeae 6S chromosomes. It is suggested that Rfg1 may be allelic to the gene determining the restoration of rye CMS caused by the Pampa (P) cytoplasm (chromosome 4RL) and to Rfc4 that on rye addition lines of chromosome 4RL restores male fertility of hexaploid wheat with T. timopheevi cytoplasm. Homoeoallelism to two loci for cytoplasmic-male-sterility restoration on chromosomes 6AS and 6BS in hexaploid wheat is also suggested. Received: 1 December 1997 / Accepted: 10 February 1998     

Cytoplasmic Male Sterility in Barley. Xi. the msm2 Cytoplasm

A new cytoplasmic male sterility in barley (Hordeum vulgare s.l.) is described and designated as msm2. The cytoplasm was derived from a selection of the wild progenitor of barley (H. vulgare ssp. spontaneum). This selection, 79BS14-3, originates from the Southern Coastal Plain of Israel. The selection 79BS14-3 has a normal spike fertility in Finland. When 79BS14-3 was crossed by cv. Adorra, the F₁ displayed partial male fertility and progeny of recurrent backcrosses with cv. Adorra were completely male sterile. Evidently 79BS14-3 is a carrier of a recessive or semidominant restorer gene of fertility. The dominant restorer gene Rfm1a for another cytoplasmic male sterility, msm1, is also effective in msm2 cytoplasm. The different partial fertility restoration properties of msm2 and msm1 cause these cytoplasms to be regarded as being distinct. Seventy spontaneum accessions from Israel have been studied for their capacity to produce F₁ restoration of male fertility both in msm1 and in msm2 cytoplasms with a cv. Adorra-like seed parent (nuclear gene) background. The msm2 cytoplasm shows partial restoration more commonly than msm1 in these F₁ combinations. The mean restoration percentage per accession for msm2 is 28, and for msm1 4. Most of the F₁ seed set differences of the two cytoplasms are statistically significant. When estimated with partially restored F₁ combinations, msm2 cytoplasm appeared to be about 50 times more sensitive to the male fertility-promoting genes present in the spontaneum accessions. The spontaneum sample from Central and Western Negev, which has been found to be devoid of restoration ability in msm1 cytoplasm, had only low partial restoration ability in msm2 (mean 0.3%). The female fertility of msm2 appears normal. The new msm2 cytoplasm could be useful in producing hybrid barley.     

Developments of functional markers for <Emphasis Type="Italic">Fom</Emphasis>-<Emphasis Type="Italic">2</Emphasis>-mediated fusarium wilt resistance based on single nucleotide polymorphism in melon (<Emphasis Type="Italic">Cucumis melo</Emphasis> L.)

Three single nucleotide polymorphism (SNP) sites in which amino acids had changed were detected by sequence analysis within the leucine-rich repeat (LRR) region of the Fom-2 gene. Cleaved amplified polymorphic sequence (CAPS) and allele-specific PCR (AS-PCR) methods were employed to explore the SNP validation linked to fusarium wilt resistance in the F₁ and F₂ generations simultaneously. Homozygous- and heterozygous-resistant genotypes and homozygous-susceptible genotype could be clearly distinguished using the CAPS method, and three detected SNP sites were observed to be linked to fusarium wilt resistance, with a segregation ratio of 1:2:1 in the F₂ generation. In addition, heterozygous-resistant and homozygous-susceptible genotypes could be clearly distinguished in the F₁ generation using the AS-PCR method, showing a 3:1 segregation in terms of resistant and susceptible genotypes in the F₂ generation. We therefore developed SNP-based functional markers (FMs) and identified some melon germplasm resistant to fusarium wilt by FM analysis within melon species. In conclusion, the SNP-based FMs originating from the SNP site of the Fom-2 LRR region were determined to be linked to fusarium wilt resistance and showed promise in the enhancement of breeding in melon.