Marker-assisted selection of Fusarium wilt-resistant and gynoecious melon (Cucumis melo L.)

Abstract

ABSTRACT. In this study, molecular markers were designed based on the sex determination genes ACS7 (A) and WIP1 (G) and the domain in the Fusarium oxysporum-resistant gene Fom-2 (F) in order to achieve selection of F. oxysporum-resistant gynoecious melon plants. Markers of A and F are cleaved amplified polymorphic sequences that distinguish alleles according to restriction analysis. Twenty F 1 and 1863 F 2 plants derived from the crosses between the gynoecious line WI998 and the Fusarium wilt-resistant line MR-1 were genotyped based on the markers. The results showed that the polymerase chain reaction and enzyme digestion results could be effectively used to identify plants with the AAggFF genotype in F 2 populations. In the F 2 population, 35 gynoecious wilt-resistant plants were selected by marker-assisted selection and were confirmed by disease infection assays, demonstrating that these markers can be used in breeding to select F. oxysporum-resistant gynoecious melon plants.

Analyzing genetic diversity in luffa and developing a Fusarium wilt-susceptible linked SNP marker through a single plant genome-wide association (sp-GWAS) study

“…The cut roots were then soaked in a buffer containing Fusarium spore suspension (2.5 × 10 6 spores/mL) for 30 min before being replanted in pots with clean soil mixture (peat: vermiculite = 3:1) for cultivation. Symptom evaluation was conducted 7, 14, and 21 days after inoculation, and disease severity was classified on a scale from 0 to 5 [ 57 ] (where level 0 indicates no symptom, level 1 represents yellowing or wilting of cotyledons; level 2 indicates yellowing or wilting of the first true leaf; level 3 indicates the yellowing or wilting of two true leaves; level 4 indicates yellowing or wilting of at least half of plant leaf; and level 5 indicates plant death). After recording disease severity at 21 days post- inoculation, the resistance status of each individual was determined based on their disease rank: individuals with ranks ranging from 0 to 1 were classified as resistant, while those with ranks exceeding 2 were classified as susceptible.…”

Novel Genomic Regions of Fusarium Wilt Resistance in Bottle Gourd [Lagenaria siceraria (Mol.) Standl.] Discovered in Genome-Wide Association Study

“…Leaf damage was used as a main index to evaluate resistant/susceptible phenotypic traits. The standard reported by Gao et al (2015) and Xu et al (2016) was further improved and implemented with a few modifications. We classified the phenotypes of plants according to a 0-4 scale as follows: level 0, no disease symptoms, i.e., immune (I); level 1, slight disease symptoms, featured by less than 25% of leaves with disease symptoms, with normal plant growth, i.e., highly resistant (HR); level 2, slight wilt symptoms, featured by 25-50% of leaves with disease symptoms, i.e., resistant (R); level 3, moderate wilt symptoms, featured by 50-90% of leaves with disease symptoms, i.e., susceptible (S); and level 4, completely wilted or dead plants, i.e., highly susceptible (HS; Supplementary Figure 2).…”

“…The ANOVA results showed that the broad-sense heritability (h 2 ) was 87.19% across the 2 years (Table 1), suggesting that the genetic effect played a predominant role in the phenotypic variation of FW resistance in bottle gourd. We divided the DI into five levels (Supplementary Figure 2): immune (level 0), highly resistant (level 1), resistant (level 2), susceptible (level 3), and highly susceptible (level 4), according to relevant previous studies (Gao et al, 2015;Xu et al, 2016). Only a tiny percentage of accessions had DI values less than 15% (8 in 2019 and 1 in 2020), whereas the majority of the accessions were within the range of 15.01-45% (35 in 2019 and 28 in 2020) and 45.01-75% (37 in 2019 and 42 in 2020).…”

Genomic Tools and Their Implications for Vegetable Breeding

“…In addition, two male-sterile watermelon lines were developed via backcrossing using both the 'ms' male sterility and 'dg' delayed-green seedling markers (Zhang et al, 1996). Similarly, a melon breeding line with both F. oxysporum-resistance genes and gynoecious traits was successfully selected using molecular markers associated with the sex determination genes ACS7 and WIP1 and the F. oxysporum-resistance gene Fom-2 (Gao et al, 2015 Table 5. Molecular markers associated with disease resistance and other traits used for marker-assisted selection in melon, watermelon, and cucumber lines with multiple lateral branching traits were selected from a backcrossing population of cucumber using five associated markers (Fazio et al, 2003;Robbins et al, 2008).…”