Identification of QTLs involved in the resistance to South American leaf blight (Microcyclus ulei) in the rubber tree

• Published in: Theoretical and applied genetics Vol. 100; no. 6; pp. 975 - 984
• Main Authors: LESPINASSE, D, GRIVET, L, TROISPOUX, V, RODIER-GOUD, M, PINARD, F, SEGUIN, M
• Format: Journal Article
• Language: English
• Published: Heidelberg Springer 01.04.2000; Berlin Springer Nature B.V
• Subjects: Agronomy. Soil science and plant productions; Biological and medical sciences; Cloning; Determinism; Fundamental and applied biological sciences. Psychology; Fungi; Genetics and breeding of economic plants; Hevea brasiliensis; Leaves; Microcyclus ulei; Pest resistance; Plant pathogens; Rubber; Varietal selection. Specialized plant breeding, plant breeding aims; South America; America; Guyana; East Asia; Africa; Genetic mapping; Quantitative character; Chromosome; Plant leaf; Microcyclus ulei; Fungi; Progeny; Improvement; Microorganism resistance; Hevea; Dicotyledones; Angiospermae; Interspecific hybridization; Euphorbiaceae; Ascomycetes; Spermatophyta; Thallophyta
• ISSN: 0040-5752; 1432-2242
• DOI: 10.1007/s001220051379

South American leaf blight (SALB) is a disease of the rubber tree caused by the fungus Microcyclus ulei. Quantitative trait loci (QTLs) for resistance were mapped using 195 F^sub 1^ progeny individuals derived from the cross between a susceptible cultivated clone, PB260, and a resistant clone, RO38, derived from interspecific hybridization. The resistance level of the progeny individuals was evaluated in controlled conditions. The reaction type (RT) and the lesion diameter (LD) were measured on immature leaves after artificial inoculation of the fungus. Five different strains of the fungus were used, all highly sporulating on PB260. Among those, four did not sporulate and one sporulated partially on RO38. Both pseudo-testcross parental genetic maps and the consensus map were constructed. The search for QTLs was performed using the Kruskal-Wallis marker-by-marker test and the Interval-Mapping method for the three maps. Eight QTLs for resistance were identified on the RO38 map. Only one QTL was detected on the PB260 map. The analysis of the F^sub 1^ consensus map confirmed results obtained with the parental maps. A common QTL was detected for resistance to the five strains for both RT and LD. Two QTLs were common for complete resistance to four strains, for RT and LD respectively. Resistance determinism for complete and partial resistance, and perspectives for breeding for durable resistance to SALB are discussed.[PUBLICATION ABSTRACT]