Plant Genome II Conference
Town & Country Conference Center, San Diego, CA, January, 1994.
PG-II: A DETAILED GENETIC LINKAGE MAP INCLUDING A CITRUS TRISTEZA
VIRUS RESISTANCE GENE DERIVED FROM A CROSS BETWEEN TWO
INTERGENERIC CITRUS X PONCIRUS HYBRIDS
A DETAILED GENETIC LINKAGE MAP INCLUDING A CITRUS TRISTEZA
VIRUS RESISTANCE GENE DERIVED FROM A CROSS BETWEEN TWO
INTERGENERIC CITRUS X PONCIRUS HYBRIDS.
Frank Suozhan Chenq*, Mikeal L. Roose, Claire T. Federici, and
Ricarda S. Kupper. Department of Botany and Plant Sciences
University of California, Riverside, CA 92521. *Department of
Horticultural Sciences, Cornell University, Geneva, NY 14456.
A detailed genetic linkage map was developed from a cross
between two citrus rootstocks, 'Sacaton' citrumelo (Citrus
paradisi x Poncirus trifoliata) and 'Troyer' citrange (C.
sinensis x P. trifoliata) using the JOINMAP program [P. Stam, The
Plant Cell 3:739 (1993)]. It includes 53 codominant isozyme and
RFLP markers and 106 dominant RAPD markers on 9 linkage groups
that presumably correspond to the 9 citrus chromosomes. The
total map length was 530 cM and 6 markers were unlinked. Bulked
segregant analysis was used to locate a gene for resistance to
citrus tristeza virus (CTV) in this population. Replicate
cuttings of the mapping population were inoculated with CTV,
grown in a greenhouse, and resistance determined using an ELISA
test for CTV. Resistance segregated as a single dominant gene.
10 RAPD markers were mapped within 5 cM of the CTV resistance
gene and one RAPD marker showed complete cosegregation with the
gene. However, this marker is homozygous in Poncirus, whereas
CTV resistance is heterozygous, so the marker is informative in
only some crosses.
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