Relationship Between Genetic Distance Based On Molecular Markers And Heterosis And Combining Ability Of Wheat

Heterosis is one of important approaches to increase crop yield and improve quality, and the quick and accurate method to predict the heterosis is helpful to select good hybrids with strong heterosis. Eight wheat parents with different characters were crossed in an dialed mating system in order to evaluate the heterosis and combining ability of the 17 characters. The relationship between genetic distance based on SSR and ISSR markers and heterosis and combining ability of wheat was investigated. The results show that:(1) The polymorphisms among the 8 parents were high. 287 pairs of SSR primers amplified 644 bands, including 560 polymorphic bands (87%). For each pairs of SSR primer, 1 to 5 fragments were detected, with an average of 1.95. The GD between parents varied from 0.251 to 0.425, with the average of 0.361. The GD between Yumai 66 and Yumai 2 was the highest and that between Yumai 49 and Yumai 2 the lowest. 12 out of 33 inter simple sequence repeats (ISSR) markers amplified 291 bands, including 194 polymorphic bands (67%), with an average of 24.25. The GD between parents varied from 0.302 to 0.436, with the average of 0.384. The GD between Yumai 66 and Yumai 54 was the highest and that between Yumai 49 and Yumai 2 the lowest.(2)Significant correlation between the GD based on SSR markers and that based on ISSR markers was found(r=0.832). Therefore, it can be proved that the genetic differences detected by SSR and ISSR markers are same, and the two kinds of markers can be used to detect the GD between parents.(3)The correlation coefficients between GD based on SSR markers and heterosis of each trait except for plant height of 28 F| hybrids were all not significant. The correlation coefficients between GD based on ISSR markers and heterosis of each trait except for width of flag leaf and plant height of F| hybrids were all not significant. However, the correlation coefficients had been improved greatly by the analysis for 12 F₁ hybrids selected from the 28 F₁ hybrids. The correlation coefficients between GD based on SSR markers and H_b of grain number per ear of F₁ hybrids were significant. The correlation coefficients between GD based on SSR markers and H_m of grain number per ear and...