Plant Genome I Conference
Town & Country Conference Center, San Diego, CA, November, 1992.
PG-I: 53pg1
IDENTIFICATION OF GENES INFLUENCING MORPHOLOGICAL AND
PHYSIOLOGICAL TRAITS IN APPLE.
D. Lawson, M. Hemmat, and N. Weeden, Department Of Horticultural
Sciences, Cornell Univ., Geneva, NY 14456.
A linkage map consisting of over 300 markers was, developed
for an apple progeny produced from a White Angel by Rome Beauty
cross. The markers were used to identify and characterize major
genes controlling segregating traits. Analysis was performed
using a simple EXCEL-based screening program that easily and
efficiently identified the approximate position of these genes.
Markers for known single gene characters such as resistance to
powdery mildew were readily identified. A single gene controlled
an important difference in branching habit, and another gene
governed the presence or absence of root suckers. Variability in
spring bud break was primarily determined by a single locus, and
time of blooming appeared to be controlled by another gene.
Persistent calyx, an important taxonomic character, was
controlled by two genes, although environment and other factors
not segregating in the cross influenced the expression of the
trait. Major genes also were found affecting precocity, fruit
size, and fruit coloration. The several genes affecting fruit
color were partially characterized with regard to the role each
played in generating the complete phenotype. Our results
demonstrate that relatively complete linkage maps constitute
valuable tools for furthering our understanding of the
inheritance of traits in woody perennial crops.
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