Male Sterile Rice Lines Developed From US Varieties.

Male-sterile (MS) lines for hybrid rice breeding have been developed in Arkansas by crossing genetically widely divergent accessions from the US Rice Germplasm Collection.  Frequently the parent lines are from geographically distant origins as well.  However, recent attempts to create male-sterile lines using US cultivars have also been successful.  Because this source of MS begins with cultivars that have been selected for adaptation and grain characteristics for our target market, selection for acceptable hybrids potentially could be faster.  The cultivars Francis, Wells, Spring, Cybonnet, M202, Bengal, Jupiter, and a local wild volunteer were crossed with established maintainer (B lines) from Asia.  Twelve male-sterile lines were identified from crosses where the female was a US cultivar. These selected MS plants then were planted in the greenhouse under short, cool days to determine if they were 2-line or 3-line MS.  Those which became fertile in the winter environment were 2-line, those that remained sterile were 3-line.  Test crosses of these male sterile lines will be made and evaluated.