lntrogression of Bacterial Leaf Blight Resistance Gene from Oryza Minuta J.B. Presl. Ex C. B. Presl. into New Rice Type (Oryza sativa L.)

Abstract

F1 Hybrids, backcross progenies, advanced introgression lines (2n=24) and monosomic alien addition lines or MAALs (2n=25) were successfully produced following embryo rescue between an elite new plant type (NPT) breeding line of Oryza sativa (2n=24, AA) and a wild species, O. minuta (2n=48, BBCC). F1 hybrids performance were intermediate between the parents. The F1 hybrids had 36 chromosomes indicating having 12 chromosome A from O. sativa and 12 B and 12 C from O. minuta. THE BACK CROSS progenies had different chromosome number indicating abnormal meiosis of the hybrids and back cross progenies. Plant with 2n=24 and 25 chromosomes were obtained in BC4FI. The hybrids and backcross progenies were susceptible to bacterial leaf blight (BB). However, several of the 2n=24 plants derived resistant plant to bacterial leaf blight race 1 of the Philippines races. The gene is different from introgressed gene intio rice from O. longistaminata ( Xa21) and from O. Minuta Acc. 101141

I Key words: Oryza minuta, MAALS, Bacterial leaf blight