Submitted to: Arkansas Experiment Station Research Series
Publication Type: Experiment Station
Publication Acceptance Date: 12/31/2006
Publication Date: 8/1/2007
Citation: Rutger, J.N., Lee, F.N., Bryant, R.J. 2007. Three Early Flowering Germplasms of a Blast Disease-Resistant Indica Rice for U.S. Rice Improveemnt Programs. Arkansas Experiment Station Research Series. 550: p.127-131. Interpretive Summary: This paper describes 3 early flowering germplasms of the famous blast disease resistant indica cultivar OL5 from Colombia. OL5 was a month too late in maturity for the the US, these lines are significantly earlier and retain blast resistance, making them useful for US breeders.
Technical Abstract: Three early flowering indica germplasms of rice (Oryza sativa L.), indica-16 through indica-18, are described. These three lines are induced early flowering mutants of Oryzica llanos 5 (PI 584668, henceforth abbreviated as OL5), a highly blast disease [Pyricularia grisea (Cooke) Sacc.] resistant cultivar from Colombia, which in itself is a month too late in maturity for the US. These mutants are part of a base broadening effort to develop indicas for the US, where very narrow genetic bases, essentially all in japonicas, have evolved because of need for adaptation to temperate climates. These three germplasm lines are 24 to 36 days earlier than the parent, making them 6 to 18 days later than the southern tropical japonica long grain cultivar Francis (PI 632447). These germplasms retain the blast resistance of the OL5 parent. Their early maturity and blast resistance make them useful sources of indica diversity for US rice improvement programs.