Author
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Krupinsky, Joseph |
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Berdahl, John |
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Submitted to: Plant Disease
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 8/18/2000 Publication Date: N/A Citation: N/A Interpretive Summary: Intermediate wheatgrass is a forage grass that is widely grown in the northern Great Plains. Forage production of intermediate wheatgrass can be reduced by plant diseases. Methods were developed to select plants that were resistant to diseases caused by two fungi, Fusarium graminearum and Bipolaris sorokiniana. Methods were based on the number of intermediate wheatgrass plants that were healthy after being exposed to fungal diseases With one fungus, F. graminearum, more sick plants were obtained when fungus-infested wheat seed was mixed with the potting medium used to cover intermediate wheatgrass seed. With another fungus, B. sorokiniana, more sick plants were obtained when fungus-infested wheat seed was sprinkled over the seed before the seed was covered with potting medium. Intermediate wheatgrass varieties, Reliant and Manska, were more resistant to B. sorokiniana than to F. graminearum. Resistant plants were selected from both varieties to start four intermediate wheatgrass populations. When resistant plants were intercrossed, there was an increase in the percentage of progeny plants that were healthier than the original parent population. Technical Abstract: Forage yield and persistence of intermediate wheatgrass and pubescent intermediate wheatgrass can be adversely affected by root rot and/or seedling blight diseases caused by Fusarium graminearum and/or Bipolaris sorokiniana. Methods were evaluated for selecting resistant intermediate wheatgrass plants that were based on the number of seedlings surviving after being exposed to fungal diseases. With F. graminearum, the lowest seedling survival was obtained using fungus-infested sterile wheat seed that was mixed with the potting medium above the seed. With B. sorokiniana, the lowest seedling survival was obtained using fungus- infested sterile wheat seed that was placed with the seed before the seed was covered with potting medium. Intermediate wheatgrass cultivars, Reliant and Manska, exhibited more resistant to B. sorokiniana than to F. graminearum. Putative resistant plants were selected from both Reliant and dManska for B. sorokiniana and F. graminearum to initiate four populations. When plants from half-sib families that were selected for resistance were intercrossed, subsequent selection cycles for B. sorokiniana resistance had progressively higher percentages of surviving seedlings compared to the original base population. Progress for F. graminearum resistance was evident in one of two populations. Thus, progressive improvement in seedling survival was realized for three of four populations selected for resistance using two cycles of recurrent phenotypic selection among and within half-sib families. |
