Relationships among Early European Maize Inbreds: I. Genetic Diversity among Flint and Dent Lines Revealed by RFLPs

Abstract

Restriction fragment length polymorphisms (RFLPs) have been proposed for characterizing genetic diversity of maize (Zea mays L.) germplasm. Fifty‐seven elite inbred lines representative of early‐maturing European flint and dent heterotic groups were assayed for RFLPs with 188 clone—enzyme combinations (98 genomic DNA clones, 2 restriction enzymes). Objectives of this study were to (i) investigate the amount of variation for RFLPs in these materials, (ii) determine the level of genetic diversity within and between heterotic groups, and (iii) examine the usefulness of RFLPs for assigning inbred lines to heterotic groups. All DNA clones detected polymorphism with at least one enzyme. About half of all RFLP patterns were common to the flint and dent lines, and a quarter was specific to the lines of each heterotic group. Genetic similarity (GS), calculated from RFLP data as Dice's similarity coefficient, ranged from 0.25 to 0.72 between unrelated pairs of lines. Mean GS for unrelated line combinations within the flint (0.425) and dent (0.414) heterotic groups were considerably greater than for flint × dent line combinations (0.344). All flint and dent inbreds showed a smaller mean GS to lines from the other hererotic group than to unrelated lines from the same heterotic group. For lines of mixed origin, the difference in mean GS to flint lines and to dent lines was consistent with the expected genomic proportions from each heterotic group based on pedigrees. Principal coordinate analysis of GS estimates resulted in a separate grouping of flint and dent lines. Results from this study corroborate the usefulness of RFLPs for identification of lines for assigning inbreds into heterotic groups. For the latter purpose, it seems possible to confine RFLP assays to a smaller number of clone—enzyme combinations with increased discriminatory power between lines from different heterotic groups.

Genetic structure and eco-geographical differentiation of cultivated Hsien rice (Oryza sativa L. subsp. indica) in China revealed by microsatellites

“…According to Messmer et al it is difficult to classify varieties as types being potentially valuable in hybrid development by geographic origin or endosperm type alone, because many varieties were mixed in origin, or were introgressed between each other [38]. In addition, pedigree relationships revealed by DNA markers could only predict the heterosis of hybrids developed by parents with certain levels of differentiation [36][37][38][39][40].…”

Selection of SSR Sets in Assignment to Dent and Flint Groups of Maize Inbred Lines Derived from European Hybrids

“…Molecular markers that directly evaluate genetic differences between inbred lines have been used to assess the genetic diversity among them (Melchinger 1999) and to assign inbred lines to groups of USA dent germplasm (Melchinger et al 1991), European germplasm (Messmer et al 1992a, 1992b, Boppenmaier et al 1992, Chitto et al 2000, and USA dent and European germplasms (Dubreuil et al 1996). The cost, labor, and time required for molecular marker analysis are major constraints on the use of marker technology in breeding systems (Stuber et al 1999).…”

Inter- and intra-population variation of local maize (Zea mays L.) populations from Slovakia and Czech Republic

“…They have found massive application in maize studies to survey adapted and exotic populations (Kahler et al 1986;Rebourg et al 2001), historically important lines (Smith et al 1985), races Pflüger & Schlatter 1996), and other populations (Lefort-Buson et al 1991). Recent development in molecular biology methods influenced also the concept of maize populations and maize genetic resource evaluation where DNAbased markers are frequently used, mainly RFLPs (Melchinger et al 1991;Messmer et al 1992;Gauthier et al 2002), AFLPs (Marsan et al 1998), and SSRs (Heckenberger et al 2002).…”