Molecular Analysis of Oryza latifolia Desv. (CCDD Genome)-Derived Introgression Lines and Identification of Value-Added Traits for Rice (O. sativa L.) Improvement

Oryza latifolia is a tetraploid wild Oryza species with a CCDD genome that has been reported to harbor resistance to bacterial blight (BB), brown planthopper, and whitebacked planthopper. Aside from these traits, O. latifolia is also being tapped as a new source of resistance to lodging and high biomass production. To explore the genetic potential of O. latifolia as a novel genetic resource for the improvement of existing O. sativa cultivars, 27 disomic derivatives of O. latifolia monosomic alien addition lines (MAAL) were characterized for alien chromosome segment introgressions and evaluated for yield components, BB resistance, and strong stem characteristics. A total of 167 simple sequence repeat, sequence tagged site, and single nucleotide polymorphism markers, along with newly developed indel markers that were specifically designed to detect O. latifolia chromosome segment introgressions in an O. sativa background, were used to define alien introgressions in 27 disomics derived from O. latifolia MAALs. Genotype data showed that 32 unique introgressions spanning 0.31-22.73 Mb were introgressed in different combinations in each of the 27 disomic derivatives. Evaluation of the disomic derivatives for agronomic traits identified lines with putative QTLs for resistance to Philippine races 3A, 4, 9A, and 9D of BB. Putative quantitative trait loci (QTLs) conferring strong stem in 19 out of the 27 disomic derivatives studied were also identified from O. latifolia introgressions on chromosome 6.