Zongbu Yan, Wengui Yan, C.W. Deren, A. McClung

Rice is a self-pollinated crop that depends on male-sterility for F₁ hybrid seed production.  As an alternative to accessing existing male-sterile lines from other hybrid breeding programs, the program in Arkansas has created its own novel male-sterile sources.  These were developed out of germplasm accessions in the U.S. National Small Grains Collection, using lines identified in the core collection.  Wide crosses between genetically distant lines were observed in segregating populations. Plants with blank heads that clearly were not attributable to other causes such as insects, disease, etc. were observed in ratoon growth.  Those plants that had fertility restored under cooler, shorter daylength were likely environmental male-steriles (EMS), and were possible candidates for a 2-line hybrid system.  Plants which remained sterile were possibly cytoplasmic-genetic male-steriles (CMS), appropriate for a 3-line system.   Out of 200 parent lines from locations as diverse as Madagascar, Indonesia, West Africa, China, Korea, and South America, crosses and subsequent selection yielded 22 male-sterile lines.