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United States Department of Agriculture

Agricultural Research Service

Research Project: Evaluation, Enhancement, Genetics and Breeding of Lettuce, Spinach, and Melon

Location: Crop Improvement and Protection Research

Title: The inheritance of resistance to Verticillium wilt caused by race 1 isolates of Verticillium dahliae in the lettuce cultivar La Brillante.

Authors
item Hayes, Ryan
item Mchale, Leah -
item Vallad, Gary -
item Jose-Truco, Maria -
item Michelmore, Richard -
item Klosterman, Steven
item Maruthachalam, Karunakaran -
item Subbarao, Krishna -

Submitted to: Theoretical and Applied Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 26, 2011
Publication Date: May 13, 2011
Repository URL: http://10.1007/s00122-011-1603-y
Citation: Hayes, R.J., Mchale, L.K., Vallad, G.E., Jose-Truco, M., Michelmore, R.W., Klosterman, S.J., Maruthachalam, K., Subbarao, K.V. 2011. The inheritance of resistance to Verticillium wilt caused by race 1 isolates of Verticillium dahliae in the lettuce cultivar La Brillante. Theoretical and Applied Genetics. DOI 10.1007/s00122-011-1603-y.

Interpretive Summary: Verticillium wilt of lettuce caused by Verticillium dahliae can cause severe economic damage to lettuce producers. Complete resistance to race 1 isolates of the disease is available in the lettuce cultivar La Brillante and understanding the inheritance of this resistance will aid development of new resistant cultivars. Families from artificial crosses between La Brillante and three susceptible iceberg cv. were evaluated for the frequency of resistant and susceptible plants in greenhouse experiments, which was consistent with a single incompletely dominant gene conferring resistance. In addition, a recombinant inbred line (RIL) population was developed from six generations of self pollination of 95 randomly selected plants derived from a cross between the susceptible cultivar Salinas 88 and La Brillante. Each RIL was tested for resistance in replicated greenhouse and field experiments, and a genetic map of molecular markers was constructed for this cross. The analysis identified a single large effect gene, which we are naming Verticillium resistance 1 (Vr1), on chromosome 9 of lettuce. The Vr1 gene does not confer complete resistance by itself, and, it is likely that minor genes in combination with Vr1 are needed for complete resistance. The position of Vr1 is coincident with a molecular marker having DNA sequence similarities to the Ve gene found in tomato, a gene that also confers resistance to race 1 isolates of V. dahliae. These results suggest, but do not prove, the resistance in the lettuce cultivar La Brillante is due to the same type of gene found in tomato. The relatively simple inheritance of resistance in lettuce indicates that breeding procedures designed for single genes will be applicable for developing resistant cultivars.

Technical Abstract: Verticillium wilt of lettuce caused by Verticillium dahliae can cause severe economic damage to lettuce producers. Complete resistance to race 1 isolates is available in L. sativa cultivar (cv) La Brillante and understanding the inheritance of resistance will aid development of new resistant cultivars. F1 and F2 families from crosses between La Brillante and three iceberg cv. as well as a recombinant inbred line population from L. sativa cv. Salinas 88 x La Brillante were evaluated for disease incidence and disease severity in replicated greenhouse and field experiments. One hundred and six molecular markers were used to create a genetic map of Salinas 88 x La Brillante and for detection of quantitative trait loci (QTL). Segregation was consistent with a single incompletely dominant gene which we are naming Verticillium resistance 1 (Vr1). The gene described large portions of variation (R2 = 0.49 to 0.68) and was mapped to linkage group 9 coincident with a 721 nucleotide expressed sequence tag of lettuce (QGD8I16.yg.ab1) that has homology with the Ve race 1 resistance gene in tomato. The Vr1 gene does not confer complete resistance by itself, and, three experiment specific minor QTL for resistance (R2 < 0.04) were found on linkage groups 5 and 8. It is likely that minor genes in combination with Vr1 are needed for complete resistance. The relatively simple inheritance of resistance indicates that breeding procedures designed for single genes will be applicable for developing resistant cultivars. QGD8I16.yg.ab1 is a good candidate for functional analysis and development of markers suitable for marker assisted selection.

Last Modified: 9/23/2014
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