Genetic Diversity among Elite Sorghum Inbred Lines Assessed with DNA Markers and Pedigree Information

Abstract

The amount of genetic diversity in parental lines of commercial sorghum [Sorghum bicolor (L.) Moench] hybrids is unknown, yet such comprehensive knowledge could improve the effectiveness of future hybrid development programs. Restriction fragment length polymorphisms (RFLPs) and pedigree data were used to investigate the genetic relationships in a group of 58 fertility restorer (R) and 47 sterility maintainer (B) elite sorghum inbred lines. The objectives of this study were to (i) assess the level of genetic variation for RFLPs in these lines, (ii) estimate genetic similarity (GS) based on RFLPs and pedigree information for R‐ and B‐lines, and (iii) examine the agreement between RFLP‐based GS and coancestry coefficient (f) for related (f> 0) pairs of inbreds. R‐lines, derived mainly from Feterita and Zera‐zera, and B‐lines, mostly from kafir germplasm, were analyzed for RFLPs with 104 DNA probes. A total of 326 patterns of RFLP bands was observed, with 276 being common to both R‐ and B‐lines, 32 unique to R‐lines, and 18 unique to B‐lines. On average, 3.6 patterns per clone‐enzyme combination were found for R‐lines and 3.0 for B‐lines. Average GS based on RFLPs was 0.67 for R‐lines and 0.76 for B‐lines, indicating more diversity within the R‐group The average for R‐lines was 0.08 and for B‐lines 0.07. Cluster analysis of GS estimates from the entire set (105) of inbreds revealed separate groups for R‐ and B‐lines in agreement with parental types, pedigree information, and the classification system used by breeders. R‐lines clustered into two main groups, one derived mainly from Feterita and the other from Zera‐zera. B‐lines were grouped into different sub‐clusters. GS and f were positively correlated for R‐lines (r = 0.46) and for B‐lines (r = 0.43), suggesting that RFLP data may help quantify the degree of relatedness in elite sorghum germplasm.

Assessment of the genetic diversity and pattern of relationship of West African sorghum accessions using microsatellite markers

“…Similar results were also observed in maize by (Melchinger et al, 1991;Messmer et al, 1992;Dubreuil et al, 1996) and barley (Melchinger et al, 1994). Likewise, cluster analysis (CA) of 148 US maize inbreeds (Dubreuil et al, 1996) as well as B-and R-lines in sorghum (Ahnert et al, 1996) and sunflower (Hongtrakul et al, 1997) partitioned the lines in accordance with their origin from different breeding groups and pedigree information.…”

“…Moreover, the traditional inter-group crossing approach utilized by public breeders may actually dilute potential heterotic patterns. The results reported by Ahnert et al (1996) also support this conclusion.…”

Genetic Diversity of Maize Accessions (<i>Zea mays</i> L.) Cultivated from Benin Using Microsatellites Markers

“…Various molecular genetic markers such as Restriction Fragment Length Polymorphism (RFLP) [11], Amplified Fragment Length Polymorphism (AFLP) [12], Inter Simple Sequence Repeats (ISSR) [13] and Simple sequence repeats (SSR) [14] were reported to be used in the molecular characterization of various plant genetic resources. Meanwhile, the SSR loci are reported to be highly polymorphic for the basic number of repeat units between species and especially among individuals within species and populations [15].…”

Genetic differentiation, heterotic performance and grain yield determinate traits of locally adapted sorghum genotypes in contrasting environments in Ethiopia

“…Hybridization based RFLPs (Restricted Fragment Length Polymorphism) markers were the first DNA marker system identified that could differentiate homozygote and heterozygote loci (Botstein et al, 1980). RFLP markers have been used for genetic variability studies in many different crops including in sorghum (Deu et al, 2006;Ahnert et al, 1996) and in maize (Pejic et al, 1998). The RFLP marker system is technically demanding, however, and found not to be suitable for high throughput and low cost screening.…”

“…Molecular marker-based genetic distance groupings have increasingly been used in a number of crops including rice (Xie et al, 2014), triticale and in maize (Tracy and Chandler, 2006). In sorghum the most widely used grouping of inbred lines for F1 hybrid production is based on fertility restoration and maintainer status of the inbred parents, designated by R and A/B-line groups, respectively (Ahnert et al, 1996;Menz et al, 2004). These parental pools have been developed for production environments in temperate and subtropical zones where advanced and highly mechanized agricultural techniques are used (Jordan et al, 2003;Smith et al, 2010).…”