Stacking of elite indica rice genotype with bacterial blight, blast, and Brown plant hopper resistance genes through marker assisted selection

Abstract

Brown planthoppers, bacterial blight, and blast are the predominant biotic stress factors that cause tremendous yield loss in rice. To address these challenges, this study aimed to develop high-yielding rice lines resistant to multiple stresses by incorporating various resistance genes through functional/linked marker-assisted selection. The common rice variety CO51 from India was initially enhanced with the bacterial blight resistance genes xa5, xa13, and Xa21, as well as the blast resistance gene Pi54. The improved CO51 was backcrossed with the donor PTB33 to introgress the BPH resistance genes bph2 and Bph32, resulting in the development of F₁ hybrids. Marker-assisted backcrossing was employed to successively backcross these hybrids, resulting in the development of BC₁F₁ and later BC₂F₁ hybrids. Foreground selection via linked markers was performed on F₁, BC₁F₁, and BC₂F₁ hybrids by selecting plants heterozygous for all target genes and assessing their recurrent parent genome (RPG%) levels. In the BC₂F₃ generation, along with foreground selection, phenotypic selection was conducted, and 27 superior plants out of 530 with CO51 characteristics were selected. The selected plants were further subjected to quality trait analysis and phenotypic screening for resistance to bacterial blight, blast, and BPH biotypes. The bioassay confirmed that pyramiding genes or single-gene introgression enhanced resistance compared with that of the recurrent parent, CO51.The six pyramided lines, CB MAS 22059 (BB and blast), CB MAS 22030 and 22042 (BPH and BB) and CB MAS 22009,22015 and 22019 (BPH, BB and blast) are promising with high grain yield, good grain quality traits and multiple stress resistance, these lines could be released as an improved CO51 cultivars for disease prone areas.