Limits...
Rice tungro spherical virus resistance into photoperiod-insensitive japonica rice by marker-assisted selection.

Shim J, Torollo G, Angeles-Shim RB, Cabunagan RC, Choi IR, Yeo US, Ha WG - Breed. Sci. (2015)

Bottom Line: Japonica1, a rice variety bred for tropical conditions, is photoperiod-insensitive, has a high yield potential, but is susceptible to RTD and has poor grain quality.To transfer RTD resistance into Japonica1, we made two backcrosses (BC) and 8 three-way crosses (3-WC) among Japonica1 and RTSV-resistant cultivars.Among 8,876 BC1F2 and 3-WCF2 plants, 342 were selected for photoperiod-insensitivity and good grain quality.

View Article: PubMed Central - PubMed

Affiliation: Plant Breeding, Genetics, and Biotechnology Division, International Rice Research Institute , DAPO Box 7777, Metro Manila , Philippines.

ABSTRACT
Rice tungro disease (RTD) is one of the destructive and prevalent diseases in the tropical region. RTD is caused by Rice tungro spherical virus (RTSV) and Rice tungro bacilliform virus. Cultivation of japonica rice (Oryza sativa L. ssp japonica) in tropical Asia has often been restricted because most japonica cultivars are sensitive to short photoperiod, which is characteristic of tropical conditions. Japonica1, a rice variety bred for tropical conditions, is photoperiod-insensitive, has a high yield potential, but is susceptible to RTD and has poor grain quality. To transfer RTD resistance into Japonica1, we made two backcrosses (BC) and 8 three-way crosses (3-WC) among Japonica1 and RTSV-resistant cultivars. Among 8,876 BC1F2 and 3-WCF2 plants, 342 were selected for photoperiod-insensitivity and good grain quality. Photoperiod-insensitive progenies were evaluated for RTSV resistance by a bioassay and marker-assisted selection (MAS), and 22 BC1F7 and 3-WCF7 lines were selected based on the results of an observational yield trial. The results demonstrated that conventional selection for photoperiod-insensitivity and MAS for RTSV resistance can greatly facilitate the development of japonica rice that is suitable for cultivation in tropical Asia.

No MeSH data available.


Related in: MedlinePlus

Representative genotypes of 3-WCF4 plants using the SSR marker RM336 which is tightly linked to RTSV resistance. Japonica1 is susceptible whereas Hwaseong, Dongjin, Sangju, MS11, and Jinmi are resistant to RTSV. Three plants per line were examined for genotypes with RM336. Genotypes from different lines were separated by dashed lines. Underlined italic genotypes indicate segregation of genotypes in a line. M) marker, Hw) Hwaseong, Ja) Japonica1, Ji) Jinmi, Do) Dongjin, Ms) MS11, Sa) Sangju, R) resistant, S) susceptible, H) heterozygous.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4542936&req=5

f3-65_345: Representative genotypes of 3-WCF4 plants using the SSR marker RM336 which is tightly linked to RTSV resistance. Japonica1 is susceptible whereas Hwaseong, Dongjin, Sangju, MS11, and Jinmi are resistant to RTSV. Three plants per line were examined for genotypes with RM336. Genotypes from different lines were separated by dashed lines. Underlined italic genotypes indicate segregation of genotypes in a line. M) marker, Hw) Hwaseong, Ja) Japonica1, Ji) Jinmi, Do) Dongjin, Ms) MS11, Sa) Sangju, R) resistant, S) susceptible, H) heterozygous.

Mentions: A total of 462 BC1F4 and 3-WCF4 lines were planted in the field. Among the 462 lines, 78 lines were selected for MAS based on field performance. Three plants from each of the 78 lines were subjected to genotyping for RTSV resistance using RM336 (Fig. 3, Table 3). Among the 78 lines, all plants of 50 lines were found to have homozygous RTSV resistance alleles, whereas 11 lines segregated into resistant, susceptible, or heterozygous genotypes (underlined italic genotypes in Fig. 3, Table 3). It appeared that the locus linked to RM336 is heterozygous in Japonica1, and that only either of the two alleles in Japnoica1 was passed on to some progenies (genotypes indicated as ā€˜Sā€™ in Fig. 3). In case of IR97709, no segregating or susceptible lines were found among the previous 71 lines of 3-WCF3 examined for phenotypes for RTSV infection (Table 2); however, the genotype data showed segregation in the 3-WCF4 generation of IR97709 (underlined italic genotypes in Fig. 3), suggesting that the contradictory results may be due to missed inoculation of RTSV via GLH on some 3-WCF3 plants of IR97709 that might have occurred during the phenotyping of the 3-WCF3 lines. Three panicles were harvested from each of the 60 BC1F4 and 3-WCF4 lines that have homozygous or heterozygous RTSV resistance alleles (Table 3), and a total of 180 lines were advanced to the next generation (Table 4). Another MAS for RTSV resistance for 180 BC1F5 and 3-WCF5 lines identified 62 lines to be homozygous for RTSV resistance alleles. The grains of 62 lines were dehulled and evaluated by visual examination. Forty-two lines were selected for good grain quality (Table 4). Three panicles were taken from each of the 42 lines and consequently a total of 126 lines were advanced to the next generation for observatory yield trial (OYT). Based on yield performance and agronomic traits in the OYT, we finally selected 22 lines (Table 5). The 22 lines selected showed a yield higher compared to MS11 and Japonica1 (Table 5).


Rice tungro spherical virus resistance into photoperiod-insensitive japonica rice by marker-assisted selection.

Shim J, Torollo G, Angeles-Shim RB, Cabunagan RC, Choi IR, Yeo US, Ha WG - Breed. Sci. (2015)

Representative genotypes of 3-WCF4 plants using the SSR marker RM336 which is tightly linked to RTSV resistance. Japonica1 is susceptible whereas Hwaseong, Dongjin, Sangju, MS11, and Jinmi are resistant to RTSV. Three plants per line were examined for genotypes with RM336. Genotypes from different lines were separated by dashed lines. Underlined italic genotypes indicate segregation of genotypes in a line. M) marker, Hw) Hwaseong, Ja) Japonica1, Ji) Jinmi, Do) Dongjin, Ms) MS11, Sa) Sangju, R) resistant, S) susceptible, H) heterozygous.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4542936&req=5

f3-65_345: Representative genotypes of 3-WCF4 plants using the SSR marker RM336 which is tightly linked to RTSV resistance. Japonica1 is susceptible whereas Hwaseong, Dongjin, Sangju, MS11, and Jinmi are resistant to RTSV. Three plants per line were examined for genotypes with RM336. Genotypes from different lines were separated by dashed lines. Underlined italic genotypes indicate segregation of genotypes in a line. M) marker, Hw) Hwaseong, Ja) Japonica1, Ji) Jinmi, Do) Dongjin, Ms) MS11, Sa) Sangju, R) resistant, S) susceptible, H) heterozygous.
Mentions: A total of 462 BC1F4 and 3-WCF4 lines were planted in the field. Among the 462 lines, 78 lines were selected for MAS based on field performance. Three plants from each of the 78 lines were subjected to genotyping for RTSV resistance using RM336 (Fig. 3, Table 3). Among the 78 lines, all plants of 50 lines were found to have homozygous RTSV resistance alleles, whereas 11 lines segregated into resistant, susceptible, or heterozygous genotypes (underlined italic genotypes in Fig. 3, Table 3). It appeared that the locus linked to RM336 is heterozygous in Japonica1, and that only either of the two alleles in Japnoica1 was passed on to some progenies (genotypes indicated as ā€˜Sā€™ in Fig. 3). In case of IR97709, no segregating or susceptible lines were found among the previous 71 lines of 3-WCF3 examined for phenotypes for RTSV infection (Table 2); however, the genotype data showed segregation in the 3-WCF4 generation of IR97709 (underlined italic genotypes in Fig. 3), suggesting that the contradictory results may be due to missed inoculation of RTSV via GLH on some 3-WCF3 plants of IR97709 that might have occurred during the phenotyping of the 3-WCF3 lines. Three panicles were harvested from each of the 60 BC1F4 and 3-WCF4 lines that have homozygous or heterozygous RTSV resistance alleles (Table 3), and a total of 180 lines were advanced to the next generation (Table 4). Another MAS for RTSV resistance for 180 BC1F5 and 3-WCF5 lines identified 62 lines to be homozygous for RTSV resistance alleles. The grains of 62 lines were dehulled and evaluated by visual examination. Forty-two lines were selected for good grain quality (Table 4). Three panicles were taken from each of the 42 lines and consequently a total of 126 lines were advanced to the next generation for observatory yield trial (OYT). Based on yield performance and agronomic traits in the OYT, we finally selected 22 lines (Table 5). The 22 lines selected showed a yield higher compared to MS11 and Japonica1 (Table 5).

Bottom Line: Japonica1, a rice variety bred for tropical conditions, is photoperiod-insensitive, has a high yield potential, but is susceptible to RTD and has poor grain quality.To transfer RTD resistance into Japonica1, we made two backcrosses (BC) and 8 three-way crosses (3-WC) among Japonica1 and RTSV-resistant cultivars.Among 8,876 BC1F2 and 3-WCF2 plants, 342 were selected for photoperiod-insensitivity and good grain quality.

View Article: PubMed Central - PubMed

Affiliation: Plant Breeding, Genetics, and Biotechnology Division, International Rice Research Institute , DAPO Box 7777, Metro Manila , Philippines.

ABSTRACT
Rice tungro disease (RTD) is one of the destructive and prevalent diseases in the tropical region. RTD is caused by Rice tungro spherical virus (RTSV) and Rice tungro bacilliform virus. Cultivation of japonica rice (Oryza sativa L. ssp japonica) in tropical Asia has often been restricted because most japonica cultivars are sensitive to short photoperiod, which is characteristic of tropical conditions. Japonica1, a rice variety bred for tropical conditions, is photoperiod-insensitive, has a high yield potential, but is susceptible to RTD and has poor grain quality. To transfer RTD resistance into Japonica1, we made two backcrosses (BC) and 8 three-way crosses (3-WC) among Japonica1 and RTSV-resistant cultivars. Among 8,876 BC1F2 and 3-WCF2 plants, 342 were selected for photoperiod-insensitivity and good grain quality. Photoperiod-insensitive progenies were evaluated for RTSV resistance by a bioassay and marker-assisted selection (MAS), and 22 BC1F7 and 3-WCF7 lines were selected based on the results of an observational yield trial. The results demonstrated that conventional selection for photoperiod-insensitivity and MAS for RTSV resistance can greatly facilitate the development of japonica rice that is suitable for cultivation in tropical Asia.

No MeSH data available.


Related in: MedlinePlus