Selection for Resistance to Stemphylium botryosum in Alfalfa1
- O. L. Borges,
- E. H. Stanford and
- R. K. Webster2
Selection for resistance to Stemphylium botryosum Wallr. was practiced in the alfalfa (Medicago sativa L.) cultivars, ‘SW44’ and ‘Caliverde.’ The parental clones were evaluated by clonal and selfed progeny testing. The observations from clonal replicated experiments permitted an estimation of broadsense heritability of 49 and 75% for SW44 and Caliverde, respectively. Significant positive correlations between parental clones and their selfed progenies were obtained for both cultivars. From these results we concluded that selection for resistance to S. botryosum would be effective in both cultivars. This expectation was tested experimentally, determining the response after one cycle of selection. For this purpose, four synthetic populations were obtained by intercrossing the selected clones and two populations were developed by intercrossing the best plants within the best selfed families. All synthetics were compared with their respective unselected populations. The results showed that selection for resistance was effective in all synthetic populations. Selfed progeny tests and selfed selection were more efficient than clonal evaluation in increasing the level of resistance.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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