Herança e mapeamento da resistência à antracnose na cultivar de feijão carioca BRS Cometa
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2018-04-17
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Universidade Federal de Goiás
Resumo
The common bean anthracnose caused by the fungus Colletotrichum lindemuthianum is one of the
main diseases that impacts negatively on crop yield. The use of resistant cultivars is an efficient
tool to control this disease. However, the wide variability of C. lindemuthianum is a challenge for
breeding programs. The pyramiding of different resistance alleles is a recommended strategy
aiming to effective and durable resistance. Fourteen resistance loci to common bean anthracnose
have been identified and described so far: Co-1, Co-2, Co-3, Co-4, Co-5, Co-6, co-8, Co-11, Co-
12, Co-13, Co-14, Co-15, Co16, and Co-17. This work has aimed to: (1) evaluate common bean
resistance source based on their reaction to anthracnose in controlled environment and on the
molecular analysis with molecular markers previously identified as linked to resistance loci; (2)
test the allelic relationship among the anthracnose resistance loci present in the carioca seeded
cultivars BRS Horizonte and BRS Cometa; and (3) study the genetic inheritance and mapping the
anthracnose resistance in BRS Cometa. The phenotypic screening of the population F2 BRS
Horizonte × BRS Cometa and F2 and F2:3 Rosinha G2 × BRS Cometa were carried out using the
C. lindemuthianum pathotypes 89 and 91, respectively. The phenotypic and molecular
characterization of 26 common bean lines were performed using two pathotypes (races 73 and 81)
and seven SCAR and one STS markers. The evaluation of the reaction to disease was carried out
using a 1-to-9 scale (resistant = 1 to 3, and susceptible = 4 to 9). The genotyping of the 104 F2
plants from the Rosinha G2 × BRS Cometa cross with SNP markers was carried out using the
BARBean6K_3 Illumina Bead Chip on the Illumina Infinium HD Assay Ultra® genotyping
platform. The genomic regions flanking the SNP markers were aligned against the reference
genome of Phaseolus vulgaris, Andean variety (G19833) and Mesoamerican variety (BAT 93),
using the BLASTN tool. As result from the phenotypic characterization, BRS Cometa and other
thirteen common bean lines have been considered resistant to the races 73 and 81. The molecular
characterization result has indicated that the resistance to anthracnose in BRS Cometa can be
controlled by the Co-3 or other resistance locus in the chromosome Pv04, since BRS Cometa has
showed amplification only for markers linked to the Co-3. Results from the phenotyping of the F2BRS Horizonte × BRS Cometa population indicated that the segregation ratio for the resistance to
anthracnose has fit to the expected ratio of 15R_:1rr ( 2 = 1.24% and P = 26.41%). The segregation
ratios in the F2 and F2:3 Rosinha G2 × BRS Cometa population has fit to expected ratio of 3R_:1rr
( 2 = 0.40% and P = 50.50%) and 1RR:2Rr:1rr ( 2 = 0.0% and P = 100%), respectively,
indicating that the resistance to anthracnose in BRS Cometa is monogenic and dominant. The
anthracnose resistance locus in BRS Cometa (Co-Cometa) was mapped on Pv04. Based on the
genetic and physical distances observed between Co-Cometa and other resistance loci already
described in Pv04 (Co-3, Co-15 and Co-16), the evidences indicate that Co-Cometa is a different
locus.
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MORAIS, S. R. P. Herança e mapeamento da resistência à antracnose na cultivar de feijão carioca BRS Cometa. 2018. 69 f. Dissertação (Mestrado em Genética e Melhoramento de Plantas) - Universidade Federal de Goiás, Goiânia, 2018.