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ARS Home » Southeast Area » Mayaguez, Puerto Rico » Tropical Crops and Germplasm Research » Research » Publications at this Location » Publication #326808
Title: Reaction of the BASE 120 lines to angular leaf spot in Puerto Rico

Author
item ESTEVEZ DE JENSEN, C. - University Of Puerto Rico
item RODRIGUEZ, D. - University Of Puerto Rico
item BEAVER, JAMES - University Of Puerto Rico
item Porch, Timothy - Tim

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 1/11/2016
Publication Date: N/A
Citation: N/A

Interpretive Summary: Common bean is limited by diseases such as Angular leaf spot (ALS). The virulence of ALS isolate ALS-9029-JD2 from Juana Diaz, PR was determined by inoculating 76 bean lines of the BASE 120 trial and susceptible controls in two different screenhouse trials during June (Juana Diaz) and October (Mayaguez), 2015. Five plants of each line were spray inoculated (1 x 105 conidia ml-1) two weeks after emergence. In the first experiment, a sprinkler maintained high relative humidity (51/96%, average min./max.). Daily average temperatures registered were 24/34 0C (min./max.). Twenty one days after inoculation disease severity was evaluated using the CIAT 1-9 scale. Resistant genotypes were considered as those with disease severity scores below 3 and no synnemata emerging after 24 hours of incubation of the leaves under humid chamber conditions. Ten genotypes were resistant, 17 were moderately resistant and the remaining 51 genotypes were susceptible to the isolate ALS-9029-JD2. In the second trial of the 76 lines, eight genotypes showed resistance. These results are in agreement with the results from the trial conducted in Juana Diaz. SCAR markers SH13 and SNO2 were used to correlate the presence of the Phg-1 and Phg-2 genes with the phenotypic response of the genotypes inoculated with isolate ALS-9029-JD2. This research is aiding to identify ALS resistant germplasm that is being used for the improvement of common bean disease resistance.

Technical Abstract: Common bean (Phaseolus vulgaris L.) is limited by diseases such as Angular leaf spot (ALS), caused by Phaeoisariopsis griseola (Sacc.) Ferraris sin. Pseudocercospora griseola (Sacc.) Crous & U. Braun. The virulence of Phaeoisariopis griseola isolate ALS-9029-JD2 from Juana Diaz, PR was determined by inoculating 76 bean lines of the BASE 120 trial and susceptible controls in two different screenhouse trials during June (Juana Diaz) and October (Mayaguez), 2015. Five plants of each line were spray inoculated (1 x 105 conidia ml-1) two weeks after emergence. In the first experiment, a sprinkler maintained high relative humidity (51/96%, average min./max.). Daily average temperatures registered were 24/34 0C (min./max.). Twenty one days after inoculation disease severity was evaluated using the CIAT 1-9 scale. Resistant genotypes were considered as those with disease severity scores below 3 and no synnemata emerging after 24 hours of incubation of the leaves under humid chamber conditions. Ten genotypes were resistant, 17 were moderately resistant and the remaining 51 genotypes were susceptible to the isolate ALS-9029-JD2. In the second trial of the 76 lines, eight genotypes showed resistance. These results are in agreement with the results from the trial conducted in Juana Diaz. SCAR markers SH13 and SNO2 were used to correlate the presence of the Phg-1 and Phg-2 genes with the phenotypic response of the genotypes inoculated with isolate ALS-9029-JD2.