Development of near-isogenic Japonica rice lines with enhanced resistance to Magnaporthe grisea.
Thirteen near-isogenic lines (NILs) of japonica rice were developed via a backcross method using the recurrent parent Chucheong, which is of good eating quality but is susceptible to Magnaporthe grisea, and three blast resistant japonica donors, Seolak, Daeseong and Bongkwang. The agro-morphological traits of these NILs, such as heading date, culm length, and panicle length, were similar to those of Chucheong. In a genome-wide scan using 158 SSR markers, chromosome segments of Chucheong were identified in most polymorphic regions of the 13 NIL plants, and only a few chromosome segments were found to have been substituted by donor alleles. The genetic similarities of the 13 NILs to the recurrent parent Chucheong averaged 0.961, with a range of 0.932-0.984. Analysis of 13 major blast resistance (R) genes in these lines using specific DNA markers showed that each NIL appeared to contain some combination of the four R genes, Pib, Pii, Pik-m and Pita-2, with the first three genes being present in each line. Screening of nine M. grisea isolates revealed that one NIL M7 was resistant to all nine isolates; the remaining NILs were each resistant to between three and seven isolates, except for NIL M106, which was resistant to only two isolates. In a blast nursery experiment, all the NILs proved to be more resistant than Chucheong. These newly developed NILs have potential as commercial rice varieties because of their increased resistance to M. grisea combined with the desirable agronomic traits of Chucheong. They also provide material for studying the genetic basis of blast resistance.
Kwon
Soon-Wook
SW
National Institute of Crop Science, RDA, Suwon 441-857, Korea.
Cho
Young-Chan
YC
Kim
Yeon-Gyu
YG
Suh
Jung-Pil
JP
Jeung
Ji-Ung
JU
Roh
Jae-Hwan
JH
Lee
Sang-Kyu
SK
Jeon
Jong-Seong
JS
Yang
Sae-Jun
SJ
Lee
Young-Tae
YT
D003433:Crosses, Genetic; D017343:Genes, Plant; D005819:Genetic Markers; D007113:Immunity, Innate / Q000235:genetics; D020082:Magnaporthe / Q000302:isolation & purification; D012275:Oryza / Q000235:genetics* / Q000382:microbiology*; D010641:Phenotype; D010935:Plant Diseases / Q000235:genetics* / Q000382:microbiology*
D005819:Genetic Markers