Cucurbit Genetics Cooperative
Other Crop Genetics Cooperatives
Home About Membership Reports Gene Lists Conferences Links Search NCSU
Cucurbit Genetics Cooperative Report 2:8 (article 4) 1979

Linkage of Bacterial Wilt Resistance and Sex Expression Genes in Cucumber

A. F. Iezzoni and C. E. Peterson

Department of Horticulture, University of Wisconsin, Madison, WI 53706

Cucumber lines resistant to bacterial wilt caused by Erwinia tracheiphila were established for each of the four sex types (gynoecious, monoecious, hermaphrodite, and andromonoecious) to investigate a possible linkage between the gene for bacterial wilt resistance and the genes controlling sex expression. From the backcross data, a strong linkage was detected between the gene B for bacterial wilt resistance and the gene M for pistillate vs. perfect flowers (Table 1). Similar results were obtained from F2 data from populations in which the M and B alleles were in coupling phase (Table 2). A linkage intensity of .011 ± .0032 was calculated by the product method. Bacterial wilt segregation was consistent with a single monogenic gene as has previously been reported. However, the poor fit of the M / m locus to a 3:1 ratio in the F2 data is unexpected and is being investigated.

Table 1. BC1 data from populations in which the M and B alleles were in coupling phase

Backcross coupling phase

Mm Bb

Mm bb

mm Bb

mm bb

Total

% Recomb

MB / mb x mb / mb

102

0

0

111

213

0

1M:1m probability 50-60%
1B:1b probability 50-60%

Table 2. F2 data from populations in which the M and B alleles were in coupling phase.

F2 coupling phase

M- B-

M- bb

mm B-

mm bb

Total

% Recomb

MB / mb selfed

311

1

10

132

454

1.1±0.32

3M:1m probability approx. 0%
3B:1b probability 1-5%

Home About Membership Reports Gene Lists Conferences Links Search NCSU
Department of Horticultural Science Box 7609North Carolina State UniversityRaleigh, NC 27695-7609919-515-5363
Page citation: Wehner, T.C., Cucurbit Genetics Cooperative;
Created by T.C. Wehner and T. Ng, 1 June 2005; design by C.T. Glenn;
send questions to T.C. Wehner; last revised on 23 October, 2009