Genetic distance estimates among single cross hybrids and correlation with specific combining ability and yield in corn double cross hybrids

Abstract

ABStrACt. The objective of the present study was to correlate the genetic distances (GD) of single cross hybrids with yield, heterosis and specific combining ability (SCA) in the double cross hybrid synthesis. For this, 10 single cross commercial hybrids were used from different companies, and all the possible double hybrids were synthesized by a complete dialell. The hybrids were assessed in 15 locations in the 2005/2006 agricultural season, using the randomized complete block design with three repetitions. DNA was extracted from the single cross hybrids and 20 simple sequence repeat primers were used, nine of which were linked to the quantitative trait loci. It was ascertained that the single hybrids were superior in general to the double cross hybrids and that yield was highly correlated with heterosis and SCA (r = 0.75 and 0.82, respectively). There was no significant correlation between yield and GD (r = 0.25), but this index was at the limit of significance. There was a medium correlation between GD and heterosis (r = 0.40) and GD and SCA (r = 0.38). The intergroup hybrids placed by genetic grouping were generally more productive than intragroup hybrids, and the hybrids with GD greater than 0.84 had the maximum heterosis and SCA. It was concluded that the markers were efficient in placing hybrids in different heterosis groups and were also useful in eliminating the most negative heterosis and SCA.

Genetic distances between popcorn populations based on molecular markers and correlations with heterosis estimates made by diallel analysis of hybrids

“…correlations were extremely low and non-significant (at 5% probability), making the use of RAPD markers unfeasible for agronomic conclusions such as the prediction of hybrid heterosis and establishment of heterotic groups. Our findings corroborate similar studies that used other types of DNA markers (Lee et al, 1989;Dudley et al, 1991;Balestre et al, 2008). Regarding RAPD markers, Rinaldi et al (2007) also did not infer a significant correlation between heterosis and productivity in Brazilian popcorn populations.…”

“…Moreover, Lanza et al (1997) obtained a significant correlation between grain yield data and random amplified polymorphic DNA (RAPD)-based genetic distances. Besides, Balestre et al (2008), with the aim of correlating the genetic distance of single cross hybrids with yield, heterosis and specific combining ability (SCA) in the double cross hybrid synthesis, concluded that there was a moderate correlation between genetic distance and heterosis (r = 0.40) and genetic distance and SCA (r = 0.38), but the authors found that the molecular markers were efficient in placing hybrids in different heterotic groups and were also useful in eliminating the most negative heterosis and SCA.…”

“…Such crosses have therefore attracted interest in the world literature, in many breeding programs with different crops (Amaral Júnior et al, 1999;Scapim et al, 2002;Vieira et al, 2007;Rangel et al, 2007Rangel et al, , 2008; Aguiar et al, 2008;Balestre et al, 2008;Gonçalves et al, 2008Gonçalves et al, , 2009Vilela et al, 2008).…”

“…More recently, molecular markers have been used to detect the variation in the DNA sequence underlying the analysis of the existing genetic dissimilarity of the parents. These markers have the advantage of simplifying the screening of parents, which can be done directly in the DNA evaluation (Mohammadi and Prasanna, 2003;Crossa and Franco, 2004;Legesse et al, 2008;Balestre et al, 2008;Dandolini et al, 2008;Silva et al, 2009).…”

Prediction of maize single-cross performance by mixed linear models with microsatellite marker information

“…Thus, some methodologies have been proposed for the prediction of untested crosses, i.e., the use of the genetic distance by molecular markers in the prediction of SCA and heterosis values (Melchinger, 1999;Reif et al, 2003;Balestre et al, 2008a). However, results have demonstrated little efficacy and repeatability (Dias et al, 2004).…”