Plant Genome II Conference
Town & Country Conference Center, San Diego, CA, January, 1994.
PG-II: APPLE GENE MAPPING IN NEW ZEALAND
APPLE GENE MAPPING IN NEW ZEALAND
S.E. Gardiner, J.M. Zhu, H.C.M. Whitehead, C. Madie, *M. Lay Yee
and *E.H.A. Rikkerink. HortResearch, Batchelar Research Centre,
Palmerston North and *Mt Albert Research Centre, Auckland; NEW
ZEALAND.
The New Zealand Apple Genome Mapping Programme has been
established to aid development of new cultivars by NZ breeders
through marker assisted selection and ultimately gene transfer.
We aim to develop a linkage map of 10-20cM density, and locate
major gene loci and QTLs of agronomic importance on it.
Screening of our mapping line of 90 seedlings from a cross
between 2 cultivars has given segregation data for more than 140
markers to date (one third RFLPs, two thirds RAPDS). The mapping
population segregates for the Vf gene for scab resistance and a
number of fruit characters and we have other lines segregating
for further major gene characters, particularly for pest and
disease resistances. Large populations (>500 plants) from the
cultivar breeding programme will be used for QTL analysis.
Special populations are being created for the fine mapping
leading to isolation of disease resistance genes. We are now
developing methodology for generation of an apple YAC library
with average DNA inserts greater than 2OOkb and approximately
10,000 clones to cover 3n to 5n apple genomes. We have developed
non-radioactive methods for in situ hybridisation of DNA probes
to the very small (1-3.5um) chromosomes of apple, and present
results on chromosome localisation for three probes related to
fruit ripening.
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