The application of doubled haploid plants to population improvement in Brassica rapa

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Friesen, Holly A.
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This study investigated improvements in the efficiency of doubled haploid line (DH) applied to population improvement in B. rapa. Methods were investigated to overcome self-incompatibility in B. rapa, to improve agronomic performance of DH lines through the production of composite populations and to identify genetic variation between DH lines. Field studies on B. rapa cv. Reward determined that 3 and 5% NaCl solutions as well as bud pollination were effective at overcoming self-incompatibility. NaCl solutions were found to be more efficient than bud pollination. Composite populations were produced by random interpollination of 4, 8, 12 and 22 DH lines, developed from B. rapa cv. Reward and the B. rapa breeding line DSC-3, for two generations. Several agronomic parameters were measured at one and two field locations for the DH lines and the composite populations, respectively. Intercrossing as few as 4 DH lines from the breeding line DSC-3 and 8 DH lines from cv Reward improved population performance over that of the contributing DH lines. Random amplified polymorphic DNA (RAPD) analysis successfully characterized genetic variation in DH lines produced from cv. Reward and the breeding line DSC-3. RAPD analysis detected 40 to 83% polymorphic bands in the DH populations using five oligonucleotide primers and 17-53% and 27-47% polymorphic bands in the first composite and second composite populations, respectively. (Abstract shortened by UMI.)