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Title: Evaluation of Beta PIs from the USDA-ARS, NPGS for Rhizoctonia crown and root rot resistance, 2012

Author
item Panella, Leonard
item Vagher, Travis
item Fenwick, Ann

Submitted to: Plant Disease Management Reports
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/16/2013
Publication Date: 8/14/2013
Citation: Panella, L.W., Vagher, T.O., Fenwick, A.L. 2013. Evaluation of Beta PIs from the USDA-ARS, NPGS for Rhizoctonia crown and root rot resistance, 2012. Plant Disease Management Reports. 7:FC119.

Interpretive Summary: Thirty sea beet plant introduction (PI) accessions from the USDA-ARS Beet collection were screened for resistance to Rhizoctonia root and crown rot, at the USDA-ARS Fort Collins, CO Research Farm. Seed was planted on 18 May to moisture and furrow irrigated as needed. The field was rotary bedded to remove any plants on 18 Jun, and replanted on 20 Jun due to severe soil crusting. Beets were harvested 20 Sep with a single row lifter (pulled and cleaned by hand), and each root was rated for rot on a scale of 0 (no damage) to 7 (dead plant with root completely rotted). There were highly significant differences among entries for Disease Index in this test and good separation among entries. PIs with a DI > 3.7 (24 PIs) were not significantly different than the worst performing Plant Introduction – PI 518414, which had a DI of 5.7. The 4 most resistant PIs (PI 604511, PI 604533, PI 604510, PI 518367) were not significantly different from the highly resistant check (FC709/2) and represent potential sources of resistance to Rhizoctonia root and crown rot. There were 2 PIs that were significantly more resistant than the worst performing line but not significantly different in performance from the resistant control (FC703) – PI 604519 and PI 518360. These accessions will be retested and, if the resistance is confirmed, entered into the USDA-ARS Rhizoctonia root rot-resistance breeding program at Fort Collins, CO. These data will be entered into the USDA-ARS, NPGS GRIN database (http://www.ars-grin.gov/npgs/index.html).

Technical Abstract: Thirty sea beet (Beta vulgaris subsp. maritima (L.) Arcang) and beet (Beta vulgaris subsp. vulgaris L.) plant introduction (PI) accessions from the Beta collection of the USDA-ARS National Plant Germplasm System were screened for resistance to Rhizoctonia root and crown rot, at the USDA-ARS Fort Collins, CO Research Farm. The rhizoctonia screening nursery in 2012 was a randomized complete-block design with five replications in one-row plots (76 cm row spacing) 4 m long. Seed was planted on 18 May to moisture and furrow irrigated as needed. The field was rotary bedded to remove any plants on 18 Jun, and replanted on 20 Jun due to severe soil crusting. Beets were harvested 20 Sep with a single row lifter (pulled and cleaned by hand), and each root was rated for rot on a scale of 0 (no damage) to 7 (dead plant with root completely rotted). Because the analysis of variance does not group the entries into discrete classes, Dunnett’s one-tailed t-test was used on DI to compare entries to the resistant check (FC703), the highly resistant check (FC709-2) and the most susceptible Plant Introduction (PI 518414). There were highly significant differences among entries for Disease Index in this test and good separation among entries. PIs with a DI > 3.7 (24 PIs) were not significantly different (Dunnett’s one-tailed t-test) than the worst performing Plant Introduction – PI 518414, which had a DI of 5.7. The 4 most resistant PIs (PI 604511, PI 604533, PI 604510, PI 518367) were not significantly different (Dunnett’s one-tailed t-test) from the highly resistant check (FC709/2) and represent potential sources of resistance to Rhizoctonia root and crown rot. There were 2 PIs that were significantly more resistant than the worst performing line but not significantly different in performance from the resistant control (FC703) – PI 604519 and PI 518360. These accessions will be retested and, if the resistance is confirmed, entered into the USDA-ARS Rhizoctonia root rot-resistance breeding program at Fort Collins, CO. These data will be entered into the USDA-ARS, NPGS GRIN database (http://www.ars-grin.gov/npgs/index.html).