engleski

Combining abilities and heterosis for dry matter yield in alfalfa diallel crosses

The combining ability and heterosis for dry matter yield of seven previously selected high yielding alfalfa cultivars were estimated using a half-diallel crosses. These cultivars originated from Croatia (OS-88, Slavonka), Denmark (Resis), Bulgaria (Prista), USA (Columbia 2000) Australia (Super 10) and Argentina (Lujan). Dry matter yield of the 21 F1 progenies and their parents were evaluated during two growing seasons (2008 and 2009) at the experimental field of the Agricultural Institute Osijek in Croatia. The analysis of variance indicated significant differences between parents and F1 progenies for dry matter yield. An analysis of the components of combining ability showed that general and specific combining ability effects were highly significant. Significant positive general combining ability effects were recorded in parents OS-88 and Columbia 2000. The five F1 progenies were obtained between the six highest-yielding crosses throughout the experiment and they demonstrated significant positive specific combining ability effects. Mid-parent heterosis ranged from -18.42 to 61.47% and high-parent heterosis ranged from -22.94 to 58.70%. The highest yields, significant specific combining ability effects and highest mid and high parent heterosis were found in the progenies OS-88 x Columbia 2000, OS-88 x Super 10, Slavonka x Columbia 2000 and Slavonka x Super 10. Therefore cultivars OS-88 and Columbia 2000 demonstrated favourable genetic potential that could contribute to the improvement of alfalfa yield in our breeding programme. The results of this study indicated that the development of progenies superior in yield is possible in crosses of high yielding Medicago sativa cultivars of different geographic origin.

alfalfa; dry matter yield; diallel crosses; combining abilities; heterosis; breeding

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