Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/30/2002
Publication Date: 12/20/2002
Citation: JAN, C.C., FERNANDEZ-MARTINEZ, J.M., RUSO, J., MUNOZ-RUZ, J. REGISTRATION OF FOUR SUNFLOWER GERMPLASMS WITH RESISTANCE TO OROBANCHE CUMANA RACE F. CROP SCIENCE. 2002. V. 42 (6). P. 2217-2218. Interpretive Summary: Genetic resistance to broomrape has been introduced from wild sunflower species into cultivars since the early work on sunflower breeding in the former USSR. The widespread use of resistant cultivars has resulted in the appearance of new races of the parasite capable of overcoming the resistance genes already in use (Or1-Or5). Recent studies have shown an evolution of sunflower broomrape races in Spain, with a new race, designated F, overcoming all the known resistance genes identified thus far. This paper reports the production and the characterization of four sunflower germplasms with resistance to the F race of broomrape. These germplasms are useful in developing sunflower hybrids in areas where broomrape race F is prevalent.
Technical Abstract: Four sunflower (Helianthus annuus L.) germplasm populations, BR1 to BR4 (PI 617026 through PI 617029) resistant to the new race F of broomrape were cooperatively developed and released by the USDA-ARS, the North Dakota Agricultural Experiment Station, Fargo, ND, and the Institute de Agricultura Sostenible, CSIC, Cordoba, Spain, in January, 2001. The resistance genes of BR1 to BR4 were derived from wild perennial sunflowers Helianthus maximiliani Schrader, H. grosseserratus Martens, and H. divaricatus L. These populations will provide sunflower breeders with genetic resistance to race F of broomrape. The BR1 through BR4 germplasm populations are F4 bulks from 10 resistant F3 families grown from selected immune F2 plants. Wild perennials were used as female parents in crosses to P21. The F1 seedlings were treated with colchicine to induce chromosome doubling and restore fertility. Chromosomally doubled (D) or partially doubled (PD) heads of the initial interspecific hybrids of BR1 to BR3 were backcrossed to P21 to produce triploid BC1F1 plants having 2n=51chromosomes. The BC1F1's were crossed with HA89 to produce BC2F1 plants which had chromosome numbers ranging from 34 to 51, and were evaluated for broomrape resistance in the greenhouse. Resistant plants were either self or sib-pollinated within each group. Only the 2n=34 chromosome BC2F2 progenies were grown at Fargo, self-pollinated, and their progeny tested for broomrape resistance in the greenhouse and the field in Cordoba. Self-pollinated BC2F3 seeds from 10 resistant BC2F2 plants were grown in the greenhouse in Fargo to produce seed for release. BR1 through BR4 have plant heights of 122, 147, 139, and 103 cm, and flower 59, 64, 71, and 60 days after planting, respectively. Seeds of BR1 to BR4 are black, with 1000 seed weights of 54, 61, 26, and 47 grams, respectively, and self-pollinated seed set percentage of 72, 82, 49, and 66, indicating good self-compatibility. BR3 plants are branched; plants of the other three populations are nonbranched.