II.18. Genetic linkage map of barley chromosome 5. II. An experiment with nine widely spaced loci.
Jens Jensen and J. Helms Jørgensen, Agricultural Research Department, Danish Atomic Energy Commission Research Establishment Risø DK-4000 Roskilde, Denmark.
The experiment comprises recombination percentages from seven crosses: three two-point, three three-point, and one four-point tests, for details see Jensen and Jørgensen (1974). Some of the data have been reported previously in BGN (Jensen and Jørgensen, 1972, 1973).
The mapping procedure suggested by Jensen (1974) was applied. It utilizes jointly the information from all seven crosses and gives the following map (distances in centimorgans, cM).
The map includes four loci: nec1 (necrotic leaf spots), wst5 (white streaks), Ml-nn (= JMl-nn), and Pa4 (resistance to powdery mildew and leaf rust), which are not on the map estimated from the data in the literature (see Jensen, 1974). The order of six of the nine loci is presumably definite, but the order of nec1 and ert-b, and that of Ml-nn in relation to Ml-k and Ml-a needs further investigations.
A comparison of the present map with that estimated from the literature data (Jensen, 1974) suggested that the mapping procedure is reliable, because common distances and loci orders are in a good agreement.
References:
Jensen, J. 1974. Genetic linkage map of barley chromosome 5. I. A procedure to estimate linkage maps applied to literature data. BGN 4:40-42.
Jensen, F. and J. Helms Jørgensen. 1972. Gene mapping on chromosome S. BGN 2:29-31.
Jensen, J. and J. Helms Jørgensen. 1973. Locating some genes on barley chromosome 5. BGN 3:25-27.
Jensen, J. and J. Helms Jørgensen. 197A. The barley chromosome 5 linkage map. Extension of the map wlth four loci.- In preparation
