Utility of SSRs for Determining Genetic Similarities an Relationships in Maize Using an Agarose Gel System

Abstract

Among maize (Zea maize L.) breeders, there is a heightened awareness of the necessity for both maintaining genetic diversity for crop improvement and improving the quality of genetic resource management. Restriction fragment length polymorphisms (RFLPs) and isozymes can serve as genetic markers for estimating divergence or diversity; however, the limited number of polymorphic isozyme loci available and the labor intensive and time consuming nature of RFLPs make their use for this purpose prohibitive. Simple sequence repeats (SSRs), when resolved using agarose gels, may be a viable and costeffective alternative to RFLPs and isozymes. Ninety‐four elite maize inbred lines, representative of the genetic diversity among lines derived from the Corn Belt Dent and Southern Dent maize races, were assayed for polymorphism at 70 SSR marker loci using agarose gels. The 365 alleles identified served as raw data for estimating genetic similarities among these lines. The patterns of genetic divergence revealed by the SSR polymorphisms were consistent with known pedigrees. A cluster analysis placed the inbred lines in nine clusters that correspond to major heterotic groups or market classes for North American maize. A unique fingerprint for each inbred line could be obtained from as few as five SSR loci. The utility of polymerase chain reaction (PCR)‐based markers such as SSRs for measuring genetic diversity, for assigning lines to heterotic groups and for genetic fingerprinting equals or exceeds that of RFLP markers, a property that may prove a valuable asset for a maize breeding program.

Molecular characterization and diversity analysis in chilli pepper using simple sequence repeats (SSR) markers

“…Lower PIC values might be the result of closely related genotypes and the viceversa. Senior et al (1998) opined that marker loci with an average number of alleles running at equal frequencies will have the highest PIC value. The PIC values obtained in the present study varied from 0.39 for AVRDC PP 187 to 0.78 for AVRDC PP 18, with an average PIC value for 27 polymorphic primers to be 0.59.…”

Genetic diversity and relationships among different tomato varieties revealed by EST-SSR markers

“…The number of SSR tandem repeats can vary in a sequence, and many such variants (alleles) can exist in a population (Powell et al, 1996). SSR markers tend to be among the most polymorphic genetic marker types and have been introduced into the process of cultivar and variety identification as well as in pedigree reconstruction and genetic mapping (Holton et al, 2002;Yu et al, 2004a;Celucia et al, 2009), to analyze functional diversity (Senior et al, 1998;Leigh et al, 2003;Dreisigacker et al, 2004), and for comparative mapping (Yu et al, 2004b;Varshney et al, 2005a). Although the identification of SSRs in gene sequences of plants started as early as 1993 (Varshney et al, 2005b), full exploitation of this marker during this period was limited by the amount of sequence data available for SSR analysis, and therefore, only a few genomic SSRs were reported.…”

Diferenciação genética entre procedências de açaizeiro por marcadores RAPD e SSR

“…No caso das reações SSR, estas foram preparadas no volume de 17μL, utilizando-se de sete locos (Tabela 2), que apresentaram transferibilidade de Euterpe edulis para E. oleracea (Oliveira, 2005). Os fragmentos foram separados em gel de agarose ultrapura 1.000 (Invitrogen), na concentração de 2,5%, e separados por eletroforese, em cuba horizontal, considerado por Senior et al (1998) como eficiente na detecção de polimorfismo por microssatélites. Todos os géis foram tratados com brometo de etídio, visualizados em transiluminador de luz ultravioleta e as imagens capturadas em câmera digital e arquivadas para avaliação das bandas (Figura 1).…”