Genetic variability in melon based on microsatellite variation

Abstract

A set of 18 simple‐sequence repeat (SSR or microsatellite) markers was used to study genetic diversity in a collection of 27 melon (Cucumis melo L.) accessions, representing a broad range of wild and cultivated melons. The materials studied were highly polymorphic for SSRs and a total of 114 alleles were detected (average of 6.3 alleles per locus). Cluster analysis suggests the division of these accessions into two major groups, largely corresponding to the division of C. melo in the two subspecies agrestis and melo. The assignment of the accession to the subspecies was generally in agreement with published reports, except for those corresponding to the ‘dudaim’ and ‘chito’ cultivar groups, which, according to the observed SSR variability, should be included in subspecies agrestis. Based on cluster analysis, five groups of accessions were defined. The two most divergent groups include mainly accessions from the Mediterranean which form one group, and accessions from China, Japan, Korea and India forming the other. Both groups shared a low level of intra‐accession variation compared with the other groups, which suggests an erosion of their genetic variability because of drift and/or inbreeding. The remaining accessions, mainly from Central Africa and India, were more variable and may be an important source of genetic variation for melon breeding.

Genetic diversity among melon accessions from Iran and their relationships with melon germplasm of diverse origins using microsatellite markers

“…The mean number of allele and effective alleles for SSR loci for the 24 Iranian accessions were 4.11 and 2.38, respectively. Daning-Poleg et al (2001) Monforte et al (2003) detected 6.3 alleles on 27 wild and cultivated melons, which was similar to the mean number of allele for reference genotypes in our study (6.55). This high value was due to various subspecies of melons which they examined.…”

“…This high value was due to various subspecies of melons which they examined. The percentage of gene loci polymorphism that Katzir et al (1996) obtained using seven SSR primers on eight genotypes was 71 %, while Monforte et al (2003) found 100 % polymorphism, which was similar to our results. The difference between number of alleles in each locus and number of effective loci obtained herein shows the existence of rare alleles (alleles which have low frequency), so we can use these alleles to identify the Iranian melon genotypes by combination of some genetic loci.…”

“…A high level of molecular and morphological variability in leaf, plant, and fruit characteristics has been described in melon species (Akashi et al 2002;Monforte et al 2003;Stepansky et al 1999). C. melo is, therefore, considered the most diverse species in Cucumis (Stepansky et al 1999).…”

“…C. melo is, therefore, considered the most diverse species in Cucumis (Stepansky et al 1999). Genetic diversity studies have used isozymes (Staub et al 1997;Akashi et al 2002), RFLPs (Zheng et al 1999), RAPDs (Garcia et al 1998;Stepansky et al 1999;Mliki et al 2001;López-Sesé et al 2003;Staub et al 2004;Sensoy et al 2007;Tanaka et al 2007), AFLPs (GarciaMas et al 2000), ISSR and simple-sequence repeat (SSR) (Katzir et al 1996;Staub et al 2000;Daning-Poleg et al 2001;López-Sesé et al 2002;Monforte et al 2003;Nakata et al 2005;Tzitzikas et al 2009) to analyze variability and relationships among melon groups. These studies have assisted in the elucidation of intraspecific relationships in melons from different origins.…”

Desarrollo y aplicación de herramientas genómicas para la mejora de especies cucurbitáceas por calidad y resistencia a enfermedades.

“…Restriction Fragment Lengh Polymorphisms (RFLPs) (Neuhausen, 1992;Silberstein et al, 1999), Random Amplified Polymorphic DNA (RAPDs) (García et al, 1998;Stepansky et al, 1999;Silberstein et al, 1999;Staub et al, 2000;Zhuang et al, 2004), Amplified Fragment Lengh Polymorphisms (AFLPs) (Garcia-Mas et al, 2000), microsatellites or Simple Sequence Repeats (SSRs) (Katzir et al, 1996;Staub et al, 2000;Danin-Poleg et al, 2001;Mliki et al, 2001;Monforte et al, 2003;Zhuang et al, 2004), Internal Simple Sequence Repeats (ISSRs) (Stepansky et al, 1999) and the sequence and structural analysis of the Internal Transcribed Spacer (ITS) (Fantaccione et al, 2008). In general, similar clustering is obtained with the different types of…”