engleski

Correlation between genetic similarities of maize inbreds revealed by SSRs and grain yield of their respective crosses

The level of heterosis of the F1 maize hybrid combinations depens on genetic divergence between parents (inbred lines). The higher yielding hybrid combinations are often derived from parents originating from genetically divergent sources. SSR marker polymorphisms can be used to assess the level of genetic divergence or similarity among elite inbred lines. The objective of the investigation was to study correlation of genetic similarity for maize inbred pairs revealed by SSR vs. (1) grain yield (MPH) of their respecitve crosses. Two field experiments with RCBD in four replication and two environments were conducted in year 2001. The first experiment has 21 diallel crosses inculuding their parents (7 related inbred lines) and a second one included 21 Line x Tester croses (7 inbred lines from the previous experiment crossed to 3 testers) along with respective lines and testers. Polymorphisms were dectected with 73 public SSR markers using agarose gels. Thirty-nine useful polymorphic marker loci were selected, and they were used for calculating the Dice genetic similarity indey (GS) - (Nei and Li, 1979). Correlatin between the GS values of the 21 diallel crosses and their respective grain yield was r=0.08 for the first and r=0.40 for the second environment. When the GS value was correlated with MPH for grain yield, again there was no significant correlatin with the first (r=0.01) and poor correlation was found for the second environment (r=0.39). But the correlation between the GS values of the 21 "line x tester" crosses and their grain yield was much higher and significant values of r were obtained for both environments, r=0.86** and r=0.68**, respectively. Almost complete negative corelation was obtained between GS and MPH for grain yield (r=0.89** and r=0.86**, respectively for two environments) what would be expected if higher yield and heterosis were associated with smaller genetic similarity.

maize; SSR; genetic similarities; heterosis

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