Use of SSRs for establishing heterotic groups in subtropical maize

Abstract

Heterotic groups and patterns are of fundamental importance in hybrid breeding. The objectives of our research were to: (1) investigate the relationship of simple sequence repeats (SSR) based genetic distances between populations and panmictic midparent heterosis (PMPH) in a broad range of CIMMYT maize germplasm, (2) evaluate the usefulness of SSR markers for defining heterotic groups and patterns in subtropical germplasm, and (3) examine applications of SSR markers for broadening heterotic groups by systematic introgression of other germplasm. Published data of two diallels and one factorial evaluated for grain yield were re-analyzed to calculate the PMPH in population hybrids. Additionally, 20 pools and populations widely used in CIMMYT's breeding program were assayed with 83 SSR markers covering the entire maize genome. Correlations of squared modified Roger's distance (MRD(2)) and PMPH were mostly positive and significant, but adaption problems caused deviations in some cases. For intermediate- and early-maturity subtropical germplasm, two heterotic groups could be suggested consisting of a flint and dent composite. We concluded that the relationships between the populations obtained by SSR analyses are in excellent agreement with pedigree information. SSR markers are a valuable complementation to field trials for identifying heterotic groups and can be used to introgress exotic germplasm systematically.

Bayesian analysis of the genetic structure of a Brazilian popcorn germplasm using data from simple sequence repeats (SSR)

“…The mean values of PIC are consistent with those estimated by Reif et al (2003), Aguiar et al (2008), and Morales et al (2010) (0.60, 0.51, and 0.68, respectively). One SSR marker was reasonably informative (0.25 < PIC < 0.5), and 10 markers were highly informative (PIC < 0.5) according to Salas Fernandez et al (2009).…”

“…Additionally, the presence of private alleles found only in Clus1 and the Mixed Group, the fact that Clus1 and the Mixed Group have the two highest values of genetic diversity within populations and the low genetic differentiation value of Clus1 (0.087) provide clear evidence of the high similarity between Clus1 and the Mixed Group. These results, combined with the high degree of genetic differentiation of Clus2 and Clus3 (Table 3), could allow for the identification of heterotic groups, thus maximizing important agronomic traits in this crop (Yuan et al, 2000;Reif et al, 2003;Miranda et al, 2008).…”

“…In this context, many authors have demonstrated practical applications for molecular marker techniques using restriction fragment length polymorphisms (RFLPs) (Ajmone-Marsan et al, 1998;Benchimol et al, 2000), amplified fragment length polymorphisms (AFLPs) (Oliveira et al, 2004;Legesse et al, 2007) and simple sequence repeats (SSRs) or microsatellites (Reif et al, 2003). Genetic analyses using either Wright's F-statistics or genetic distances remain the most common focus for the characterization of genetic differentiation (Latch et al, 2006;Bracco et al, 2009).…”

Genetic diversity of the floury race of maize Avati Morotî from the Guaraní tribe in Paraguay

“…Altogether we found 13.13 alleles per locus, which is higher than the value reported by Aci et al (2013) among Algerian populations or Romay et al (2012) among Spanish germplasm with the same SSR set of loci. The number of alleles per locus was also higher than that reported in other American origins with different SSRs (Reif et al, 2003b(Reif et al, , 2004(Reif et al, , 2005(Reif et al, , 2006Wiethotler et al, 2008;Bracco et al, 2012).…”

Aplikasi Bioinformatik Untuk Studi Genetik Jagung Pro Vitamin-A

“…Bioinformatika telah diaplikasikan pada berbagai penelitian, termasuk dalam studi genetika tanaman jagung. Reif et al (2003) telah menerapkan teknik informatika dalam studi heterosis jagung tropis dan subtropis. Sementara Liu et al (2005) melakukan studi aplikasi mikro satelit untuk pemuliaan jagung pulut atau jagung ketan.…”