Molecular mapping of three nuclear male sterility mutant genes in cultivated sunflower ( Helianthus annuus L.)

The nuclear male sterility (NMS) trait is a useful tool for sunflower ( Helianthus annuus L.) breeding and genetic programs. Previously, we induced NMS mutants in cultivated line HA 89. The mutants possessed single recessive genes ms 6 , ms 7 , and ms 8 , respectively, in NMS HA 89-872, NMS HA 89-552, and NMS HA 89-747. Bulked segregant analysis based on the male-fertile and male-sterile DNA pools and 560 simple sequence repeat and insertion/deletion markers randomly selected from 17 linkage groups (LGs) were used to locate ms 6 to LG16, ms 7 to LG6, and ms 8 to LG5. Subsequent genotyping of three F2 populations of 88, 93, and 76 individuals confirmed their map positions. Additional polymorphic markers derived from four restriction fragment length polymorphism-converted sequence-tagged site primer pairs were identified. A partial linkage map consisting of eight markers was constructed for the ms 6 locus, covering a region of 69.24 cM, with markers ORS807 and ORS996 flanking the ms 6 locus at distances of 7.2 and 18.5 cM, respectively. Six markers were constructed for ms 7 , covering a region of 53.4 cM, with ORS608 and ORS1229 flanking ms 7 at distances of 2.6 and 9.5 cM, respectively. Ten markers were constructed for ms 8 , covering a region of 18.0 cM, with six markers below ms 8 and CRT518 above flanking ms 8 at distances of 7.4 and 3.8 cM, respectively. The markers and mapping information will be useful for selection of the recessive NMS genes in sunflower breeding programs.