Research Notes : United States : Evaluation of soybean germplasm for stress tolerance biological efficiency : To evaluate soybean germplasm and cultivars for stress tolerance toward : Diseases

Screening of improved soybean lines from Alabama A&M University for multiple resistance against bacterial blight, stem canker, and soybean cyst nematode in the greenhouse and in the field continued at Alabama A&M University. Lines obtained from Virginia State University in MG IV (PI 339984, PI 408039, PI 80837); MG V (PI 96089, PI 123440, PI L-76-0132, PI L-77-0049, \u27Hill\u27, \u27Essex\u27); MG VI (FC 31665, PI 407868C, PI 159322, PI 416937, PI 379621, PI 221713, PI 230978, \u27Lee\u27); MG VII (PI 423911, PI 229358); and MG VIII (PI 417134, PI 417063, PI 417061, PI 416893) were screened. Initial results indicated PI L76-0049 is resistant to bacterial blight, PI 159322 and PI 230978 are resistant to soybean cyst nematode (race 3 and 5), and PI 417061 has multiple resistance to bacterial blight and stem canker

Research Notes : United States : Evaluation of soybean germplasm for stress tolerance and biological efficiency towards : Diseases

A field study was conducted for screening and selection of improved soybean germplasm for disease resistance in 1986. The soybean crossing block consisted of 207 germplasm entries screened at flowering and at maturity. One hundred and one were resistant and moderately resistant to bacterial blight (BB)

RAPD markers associated with resistance to blackleg disease in Brassica species

Blackleg, caused by Leptosphaeria maculans, is a serious disease of Brassica species. Genetic analysis of resistance to L. maculans was carried out with 15 accessions from the USDA Brassica germplasm collections, representing diploids (A, C), and tetraploid (AC) genomes, respectively; and 9 cultivars from the National Winter Canola Variety Trials (NWCVT) all carrying AC genomes. All genotypes were screened for blackleg disease at the cotyledonary stage. The results indicated that 46% of the 24 genotypes were resistant, while 54% were susceptible. On the other hand, adult plant screening revealed that all the public genotypes were resistant. In an effort to identify molecularmarkers associated with resistance to blackleg disease, all genotypes were screened with 13 RAPD and 8 SSR markers producing 169 amplified products. Six RAPD markers (OPB01, OPE03, OPE16, OPF10, OPE12, and OPI01) were polymorphic, while the SSR markers were monomorphic. Chi-square analysis indicated that 5 amplified fragments (OPE03-4000, OPE16-1100, OPE16-1300, OPE16-1900, and OPI01- 280) from RAPD primers were significantly associated with blackleg resistance. Thus this study demonstrated that RAPD primers could be effectively used to identify DNA markers that are associatedwith blackleg disease resistance, and that resistance to L. maculans might also exist in the A and C genomes

Coconut cadang-cadang viroid and coconut tinangaja viroid

Coconut cadang-cadang viroid (CCCVd) causes the lethal cadang-cadang disease of coconut palm in the Philippines. Variants of CCCVd are associated with a foliar orange spotting syndrome of African oil palm, showing over 90% sequence identity to CCCVd from coconut, which are also mechanically transmissible, but still require testing for pathogenicity. Coconut tinangaja viroid causes the lethal tinangaja disease of coconut palm in Guam, has about 64% sequence identity to CCCVd, but differs from cadang-cadang in symptomatology. Neither disease is under control and their epidemiology is poorly understood. Viroid-like RNAs with sequence identity to CCCVd have been detected by molecular hybridization in palms and other monocotyledonous plants in many South East Asian and South Pacific countries. Their role in palm viroid epidemiology requires thorough investigatio

Transmission of soil-borne wheat mosaic virus

Call number: LD2668 .T4 1966 P122Master of Scienc

Research Notes : United States : Evaluation of soybean germplasm for stress tolerance and biological efficiency towards : Diseases

A field study was conducted for screening and selection of improved soybean germplasm for disease resistance in 1986. The soybean crossing block consisted of 207 germplasm entries screened at flowering and at maturity. One hundred and one were resistant and moderately resistant to bacterial blight (BB).</p

Research Notes : United States : Evaluation of soybean germplasm for stress tolerance biological efficiency : To evaluate soybean germplasm and cultivars for stress tolerance toward : Diseases

Screening of improved soybean lines from Alabama A&M University for multiple resistance against bacterial blight, stem canker, and soybean cyst nematode in the greenhouse and in the field continued at Alabama A&M University. Lines obtained from Virginia State University in MG IV (PI 339984, PI 408039, PI 80837); MG V (PI 96089, PI 123440, PI L-76-0132, PI L-77-0049, 'Hill', 'Essex'); MG VI (FC 31665, PI 407868C, PI 159322, PI 416937, PI 379621, PI 221713, PI 230978, 'Lee'); MG VII (PI 423911, PI 229358); and MG VIII (PI 417134, PI 417063, PI 417061, PI 416893) were screened. Initial results indicated PI L76-0049 is resistant to bacterial blight, PI 159322 and PI 230978 are resistant to soybean cyst nematode (race 3 and 5), and PI 417061 has multiple resistance to bacterial blight and stem canker.</p