Comparison of phenotypic and molecular distances to predict heterosis and F1 performance in Ethiopian mustard (Brassica carinata A. Braun)

Abstract

Predicting heterosis and F1 performance from the parental generation could largely enhance the efficiency of breeding hybrid or synthetic cultivars. This study was undertaken to determine the relationship between parental distances estimated from phenotypic traits or molecular markers with heterosis, F1 performance and general combining ability (GCA) in Ethiopian mustard (Brassica carinata). Nine inbred lines representing seven different geographic regions of Ethiopia were crossed in half-diallel. The nine parents along with their 36 F1s were evaluated in a replicated field trail at three locations in Ethiopia. Distances among the parents were calculated from 14 phenotypic traits (Euclidean distance, ED) and 182 random amplified polymorphic DNA (RAPD) markers (Jaccard's distances, JD), and correlated with heterosis, F1 performance and GCA sum of parents (GCAsum). The correlation between phenotypic and molecular distances was low (r=0.34, P< or =0.05). Parents with low molecular distance also had low phenotypic distance, but parents with high molecular distance had either high, intermediate or low phenotypic distance. Phenotypic distance was highly significantly correlated with mid-parent heterosis (r=0.53), F1 performance (r=0.61) and GCA (r=0.79) for seed yield. Phenotypic distance was also positively correlated with (1) heterosis, F1 performance and GCA for plant height and seeds plant(-1), (2) heterosis for number of pods plant(-1), and (3) F1 performance for 1,000 seed weight. Molecular distance was correlated with GCAsum (r=0.36, P< or =0.05) but not significantly with heterosis and F1 performance for seed yield. For each parent a mean distance was calculated by averaging the distances to the eight other parents. Likewise, mean heterosis was estimated by averaging the heterosis obtained when each parent is crossed with the other eight. For seed yield, both mean ED and JD were significantly correlated with GCA (r=0.90, P< or =0.01 for ED and r=0.68, P< or =0.05 for JD) and mean heterosis (r=0.79, P< or =0.05 for ED and r=0.77, P< or =0.05 for JD). In conclusion, parental distances estimated from phenotypic traits better predicted heterosis, F1 performance and GCA than distances estimated from RAPD markers.

THE RELATIONSHIP BETWEEN HETEROSIS AND GENETIC DISTANCES BASED ON SSR MARKERS IN <i>HELIANTHUS ANNUUS</i>

“…On the other hand, studies with hybridization performances conducted in mustard and alfalfa showed significant correlation between heterosis and morphological distances; whereas genetic distances calculated on the basis of DNA polymorphism (SSR, RAPD, AFLP markers) did not demonstrate such correlation (Riday et al, 2003;Teklewold and Becker, 2006). No reliable correlation was found using genetic distances by SSR markers to predict specific combining ability of sunflower parental lines (Gvodzenovic et al, 2009).…”

“…However, the results of different studies are often controversial with respect to connection between genetic distances and heterosis (Riday et al, 2003;Geleta et al, 2004;Teklewold and Becker, 2006;Zeid et al, 2003;Ghaly and Al-Sowayan, 2014;Malini and Vasanthanayaki, 2014;SenthilSingh and Manikandan, 2014). In the present research the level of heterosis of F 1 hybrids, genetic diversity of parental lines based on SSR markers, as well as its connection with specific combining ability of sunflower were studied.…”

Molecular characterization of Psyttalia lounsburyi, a candidate biocontrol agent of the olive fruit fly, and its Wolbachia symbionts as a pre-requisite for future intraspecific hybridization

“…Nevertheless, further comparisons on quantitative traits are needed to select relevant populations. One reason is that genetic distances calculated from neutral markers is only a weak predictor of heterosis in hybrid populations (Cheres et al 2000;Teklewod and Becker 2006). The availability of both COI sequences and microsatellites may also be helpful to monitor the post-release evolution of P. lounsburyi in the field and document genetic events such as drift, admixture and introgression.…”

Genetic diversity of different populations and improved growth in the F1 hybrids in the swimming crab (Portunus trituberculatus)

“…However, studies conducted in plants showed inconsistent results. For example, genetic distance was not correlated with heterosis for rice hybrid seed yield (Teklewold and Becker, 2006) and was negatively correlated with heterosis of yield (Singh et al, 2011).…”