Location: Northwest Irrigation and Soils Research
Title: Kimberly sugar beet germplasm evaluated for Rhizoctonia crown and root rot resistance in Idaho, 2023Author
Submitted to: Plant Disease Management Reports
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 1/9/2024 Publication Date: 3/12/2024 Citation: Vincill, E.D., Majumdar, R., Strausbaugh, C.A. 2024. Kimberly sugar beet germplasm evaluated for Rhizoctonia crown and root rot resistance in Idaho, 2023. Plant Disease Management Reports. 18. Article V009. Interpretive Summary: Rhizoctonia crown and root rot (RCRR) is a serious fungal root disease problem for sugar beets worldwide that is caused by Rhizoctonia solani. In-furrow chemical treatments and host resistance are the primary control measures for RCRR. However, resistance is controlled by a number of genes (quantitative trait) which makes it challenging and time consuming to introgress resistance into commercial hybrids. In order to identify additional sources of resistance, 29 lines from the USDA-ARS Kimberly, Idaho sugar beet program were evaluated along with three check cultivars for resistance to RCRR. The rhizoctonia susceptible check had 26% of its root area covered in rot and 72% of its roots were harvestable. On the other hand, the resistant check had only 6% rot and 88% of its roots were harvestable. Based on root rot, disease index, and harvestable roots, five entries (K23Rcs2, K23Rcs3, K23Rcs7, K23Rcs12, and K23Rcs27) were also significantly better than the susceptible check and not different from the resistant check. These five lines along with some other better performing entries should be evaluated again since they may serve as a starting point for identifying additional sources of resistance to R. solani. These lines will be retested and investigated further for potential release to the general public so they can be utilized to improve RCRR resistance in commercial sugar beet cultivars. Technical Abstract: Rhizoctonia crown and root rot (RCRR) is a serious fungal root disease problem for sugar beets worldwide that is caused by Rhizoctonia solani. In-furrow chemical treatments and host resistance are the primary control measures for RCRR. However, resistance is controlled by a number of genes (quantitative trait) which makes it challenging and time consuming to introgress resistance into commercial hybrids. In order to identify additional sources of resistance, 29 lines from the USDA-ARS Kimberly, Idaho sugar beet program were evaluated along with three check cultivars for resistance to RCRR. The rhizoctonia susceptible check had 26% of its root area covered in rot and 72% of its roots were harvestable. On the other hand, the resistant check had only 6% rot and 88% of its roots were harvestable. Based on root rot, disease index, and harvestable roots, five entries (K23Rcs2, K23Rcs3, K23Rcs7, K23Rcs12, and K23Rcs27) were also significantly better than the susceptible check and not different from the resistant check. These five lines along with some other better performing entries should be evaluated again since they may serve as a starting point for identifying additional sources of resistance to R. solani. These lines will be retested and investigated further for potential release to the general public so they can be utilized to improve RCRR resistance in commercial sugar beet cultivars. |