Combining ability, heterosis, genetic distance and their intercorrelations for waterlogging tolerance traits in chrysanthemum

Abstract

Waterlogging tolerance (WT) is a major objective in chrysanthemum breeding programs, and although certain genotypes with different tolerance levels have been identified, their value as parents for WT breeding is unknown. Here, twelve F 1 crosses derived from an incomplete diallel mating scheme were conducted to investigate combining ability and heterosis for WT and their relationships with parental genetic distance. The results showed that the membership function value of waterlogging (MFVW) was controlled by additive and non-additive gene effects, whereas other growth and biomass traits were mainly controlled by non-additive gene effects. The estimated broad and narrow sense heritabilities of the MFVW were 97.5 and 51.5%, respectively. Combining ability analyses indicated that 'Nannong Xuefeng' showing the largest general combining ability (GCA) effect for the MFVW was the best combiner, and identified several best cross combinations with high positive specific combining ability (SCA) effects for most WT-related traits. Mid-and high-parent heterosis occurred widely. The three distance measures, based on phenotypic traits (PD), molecular markers (GD) and markers linked with quantitative trait loci (QTL-GD), presented a nonsignificant correlation with combining ability except for the GD with GCA for the relative root fresh weight. The correlations between the QTL-GD and heterosis were significant for certain traits and generally higher than that of the PD or GD and heterosis. The SCA effects were positively correlated with heterosis for most of the WT traits (0.51 B r B 0.80). The findings benefit understanding the inheritance mode and then achieving desirable improvement for WT in chrysanthemum.

Doubled haploid based parental lines are most suitable in predicting heterosis using microsatellites and in development of highly heterotic F1hybrids inBrassica oleracea

“…Both the distance measures displayed no significant correlation with SCA of all the traits, suggesting genetic distances might not be effective in predicting SCA effects. Our results are in conformity with Su et al [73] who also reported no significant association between genetic distances and SCA in chrysanthemum. However, Tian et al [78], Lariepe et al [44] reported significant correlation between total GD and SCA for length of terminal raceme in rapeseed, for grain yield and plant height in maize, respectively.…”

“…The significantly high SCA effects manifested in desirable direction by low × low testcrosses (poor GCA effects of both male and female parents) for instance Ogu307-33A × DH-18-8-3 for days to 50% CI, Ogu1A × DH-18-8-3 for days to 50% CM, Ogu22-1A × DH-53-6 for GPW and Ogu22-1A × DH-53-6 for NCW may be attributed to dominance × dominance type of interaction having especially complementary epistatic effects [24, 69]. This inconsistent association of GCA and SCA of respective crosses for respective traits is the indication of complex interaction of genes for quantitative traits [73]. Our results are corroborated by the findings of Verma and Kalia [81] for growth and yield traits in cauliflower using SI inbred lines and Singh et al [69] for antioxidant traits using CMS lines.…”

“…Among different biometrical approaches, line × tester analysis appears to be ideal for estimating GCA effects of lines and testers, SCA effects of cross combinations, and providing information about nature of gene actions [17, 20, 41]. The extent of heterosis has been reported to be vary with mode of reproduction, genetic distance of parents, traits under investigation, developmental stage of plant and prevailing environment [27, 34, 38, 40, 44, 73]. The pair-wise parental genetic distance (GD) has been suggested as a good indicator of per se hybrid performance and recognition of heterotic groups [27, 34, 38, 40, 44, 73].…”

“…The extent of heterosis has been reported to be vary with mode of reproduction, genetic distance of parents, traits under investigation, developmental stage of plant and prevailing environment [27, 34, 38, 40, 44, 73]. The pair-wise parental genetic distance (GD) has been suggested as a good indicator of per se hybrid performance and recognition of heterotic groups [27, 34, 38, 40, 44, 73]. Different approaches are available to determine genetic distance depending upon morphological traits, horticultural data, biochemical characteristics and DNA markers based genotypic data [33, 55].…”

“…As suggested by Cress [12] that for significant heterosis the extent of parental GD is essential but is not enough to assure it and in addition, the better forecasting of heterosis is possible only when GD is lesser than a definite threshold level [4]. Furthermore, the association of GD and heterosis also depends upon the germplasm, population under investigation, methods of calculating GD [73-74]. The parents with small GD can also display high level of heterosis like closely related ecotypes in Arabidopsis resulted hybrids with significant improvement in plant biomass and seed yield [26, 32].…”