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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

Phenotypic selection criteria for photoperiod insensitivity and grain quality. (a) Difference in height among photoperiod-sensitive varieties (Sangju, Dongjin and Hwaseong) and photoperiod-insensitive varieties (MS11, Jinmi and Japonica1). (b) Typical segregation of panicle length and grain number in BC1F2 plants. Panicles from BC1F2 plants of IR97705. Scale bar equals 10 cm. (c) Typical segregation in grain chalkiness and opacity in BC1F2 plants. Grains from BC1F2 plants of IR97705.
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f2-65_345: Phenotypic selection criteria for photoperiod insensitivity and grain quality. (a) Difference in height among photoperiod-sensitive varieties (Sangju, Dongjin and Hwaseong) and photoperiod-insensitive varieties (MS11, Jinmi and Japonica1). (b) Typical segregation of panicle length and grain number in BC1F2 plants. Panicles from BC1F2 plants of IR97705. Scale bar equals 10 cm. (c) Typical segregation in grain chalkiness and opacity in BC1F2 plants. Grains from BC1F2 plants of IR97705.

Mentions: The photoperiod-sensitive japonica rice varieties typically exhibit early flowering and poor vegetative growth when grown under tropical conditions (12–14 hour day length; 25–33°C average day temperature). In the tropical condition of Philippines, the average height of highly photoperiod-sensitive japonica varieties is about 55 cm; they flower earlier than 45 days after seeding (Fig. 2A); and their panicles are shorter than 15 cm (Fig. 2B). Stricter criteria were applied for background selection of the BC1F2 and 3-WCF2 generations for photoperiod insensitivity. Plants that were taller than 75 cm; had panicles longer than 22 cm; and that flowered at or after 60 days after seeding were considered photoperiod-insensitive. The selection criteria for good grain quality include grain chalkiness, opacity, color, boldness and appearance (Webb et al. 1985). The grains were dehulled and examined by visual test. Plants with grains that are not chalky, clear translucent, bold (length/width ratio less than 1.9), and short (shorter than 5.5 mm in length) were selected (Fig. 2C).


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)

Phenotypic selection criteria for photoperiod insensitivity and grain quality. (a) Difference in height among photoperiod-sensitive varieties (Sangju, Dongjin and Hwaseong) and photoperiod-insensitive varieties (MS11, Jinmi and Japonica1). (b) Typical segregation of panicle length and grain number in BC1F2 plants. Panicles from BC1F2 plants of IR97705. Scale bar equals 10 cm. (c) Typical segregation in grain chalkiness and opacity in BC1F2 plants. Grains from BC1F2 plants of IR97705.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

f2-65_345: Phenotypic selection criteria for photoperiod insensitivity and grain quality. (a) Difference in height among photoperiod-sensitive varieties (Sangju, Dongjin and Hwaseong) and photoperiod-insensitive varieties (MS11, Jinmi and Japonica1). (b) Typical segregation of panicle length and grain number in BC1F2 plants. Panicles from BC1F2 plants of IR97705. Scale bar equals 10 cm. (c) Typical segregation in grain chalkiness and opacity in BC1F2 plants. Grains from BC1F2 plants of IR97705.
Mentions: The photoperiod-sensitive japonica rice varieties typically exhibit early flowering and poor vegetative growth when grown under tropical conditions (12–14 hour day length; 25–33°C average day temperature). In the tropical condition of Philippines, the average height of highly photoperiod-sensitive japonica varieties is about 55 cm; they flower earlier than 45 days after seeding (Fig. 2A); and their panicles are shorter than 15 cm (Fig. 2B). Stricter criteria were applied for background selection of the BC1F2 and 3-WCF2 generations for photoperiod insensitivity. Plants that were taller than 75 cm; had panicles longer than 22 cm; and that flowered at or after 60 days after seeding were considered photoperiod-insensitive. The selection criteria for good grain quality include grain chalkiness, opacity, color, boldness and appearance (Webb et al. 1985). The grains were dehulled and examined by visual test. Plants with grains that are not chalky, clear translucent, bold (length/width ratio less than 1.9), and short (shorter than 5.5 mm in length) were selected (Fig. 2C).

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