Author
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Panella, Leonard |
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Strausbaugh, Carl |
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Submitted to: Plant Disease Management Reports
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 7/7/2010 Publication Date: 8/23/2010 Citation: Panella, L.W., Strausbaugh, C.A. 2010. Beet curly top resistance of released germplasm from the USDA-ARS program at Fort Collins, CO, 2009. Plant Disease Management Reports. 4:FC071 DOI:10.1094/PDMR04. Interpretive Summary: Seventy sugar beet (Beta vulgaris L.) germplasms released from the USDA-ARS Breeding Program in Fort Collins, Colorado over the last 40 years and 27 experimental germplasm were screened for resistance to Beet severe curly top virus (BSCTV) in 2009. The curly top evaluation was conducted at the USDA-ARS North Farm in Kimberly, ID which had been in beans in 2008. The germplasm was planted on 18 May. The plots were two rows 10 ft long and 22 in row spacing and arranged in a randomized complete block design with three replications. A resistant breeding line from Betaseed, Inc., G6040, was included as a resistant check. The fields were sprinkler irrigated and hand weeded as necessary. The plant populations were thinned on 19 Jun. The plants were inoculated at on June 23 Jwith six viruliferous beet leafhoppers per plant. The beet leafhoppers were moved twice a day (right after sunrise and just before sunset) for one week. The plants were sprayed on 7 Jul to kill the beet leafhoppers. The plots were rated for foliar symptom development on using a scale of 0- 9 (0 = healthy and 9 = dead).. Data were analyzed. Disease development was uniform and severe. Other disease problems were not evident in the plot area. Only 14 germplasm (some of the FC600 series, FC403CMS, and some experimental germplasms) were not significantly different from G6040 (resistant control). Very little of the germplasm tested was selected specifically for resistance to beet curly top, except for FC600 lines. They were developed to combine resistance to BSCTV with resistance to Cercospora beticola. Nonetheless, it is important for germplasm to be screened against as many diseases as possible, because plant breeders want as much information with a germplasm as is available. Many of the germplasms under development were from a collaborative breeding project with the USDA-ARS sugar beet breeding program at Salinas, CA, and much of the germplasm from there has good resistance to beet curly top. Two of the lines that did well were experimental hybrids in which the female parent was a Salinas germplasm with good resistance to beet curly top. Some of the more recently released lines from the FC700 series also did well, although significantly worse than the resistant check. Both FC721 and FC723 were developed to combine resistance Rhizoctonia root and crown rot with resistance to beet curly, and both were significantly better than the worse performing germplasm Technical Abstract: Seventy sugar beet (Beta vulgaris L.) germplasms released from the USDA-ARS Breeding Program in Fort Collins, Colorado over the last 40 years and 27 experimental germplasm were screened for resistance to Beet severe curly top virus (BSCTV) in 2009. The curly top evaluation was conducted at the USDA-ARS North Farm in Kimberly, ID which had been in beans in 2008. The field was plowed in the fall, fertilized (75 lb N/A and 75 lb P2O5/A) on 22 Apr 09, sprayed with Ethotron (2 pt/A), and roller harrowed. The germplasm was planted (density of 142,560 seeds/A) on 18 May. The plots were two rows 10 ft long and 22 in row spacing and arranged in a randomized complete block design with three replications. A resistant breeding line from Betaseed, Inc., G6040, was included as a resistant check. The fields were sprinkler irrigated and hand weeded as necessary. The plant populations were thinned to 47,520 plants/A on 19 Jun. The plants were inoculated at the four to six leaf growth stage on 23 Jun with six viruliferous beet leafhoppers per plant. The beet leafhoppers were moved twice a day (right after sunrise and just before sunset) for one week. The plants were sprayed with Lorsban 4E (1.5 pints/A) on 7 Jul to kill the beet leafhoppers. The plots were rated for foliar symptom development on using a scale of 0- 9 (0 = healthy and 9 = dead; described in Plant Disease 91:1459-1463) in a continuous manner with all numbers between 0 and 9 possible. Data were analyzed using the general linear models procedure (Proc GLM-SAS), and Fisher’s protected least significant difference was used for mean comparisons. Disease development was uniform and severe. Other disease problems were not evident in the plot area. Only 14 germplasm (some of the FC600 series, FC403CMS, and some experimental germplasms) were not significantly different from G6040 (resistant control). Very little of the germplasm tested was selected specifically for resistance to beet curly top, except for FC600 lines. They were developed to combine resistance to BSCTV with resistance to Cercospora beticola. Nonetheless, it is important for germplasm to be screened against as many diseases as possible, because plant breeders want as much information with a germplasm as is available. Many of the germplasms under development were from a collaborative breeding project with the USDA-ARS sugar beet breeding program at Salinas, CA, and much of the germplasm from there has good resistance to beet curly top. Two of the lines that did well were experimental hybrids in which the female parent (C790-15cms and C833-tcms) was a Salinas germplasm with good resistance to beet curly top. Some of the more recently released lines from the FC700 series also did well, although significantly worse than the resistant check. Both FC721 and FC723 were developed to combine resistance Rhizoctonia root and crown rot with resistance to beet curly, and both were significantly better than the worse performing germplasm (DI = 9.0). The FC400 lines were released as parental lines for performance under Spanish growing conditions and both FC403CMS and FC401 did well. |
