Improving Blast Resistance of Rice thru Marker-assisted Gene Pyramiding

Rice blast is one of the major diseases that decrease rice production. In China, severe seeding and neck blast were reported to affect approximately 20% of hybrid rice fields in 2006. Blast is often treated using fungicides however this practice increases the input costs of production and may also post hazard in the environment and the health of the farmers. Thus, the use of resistant varieties could be a more favorable solution to protect rice from the disease.

Yuqing He and colleagues at Huazhong Agricultural University conducted introgressive hybridization to transfer genes Pi1, Pi2, and D12 to Jin 23B, a highly susceptible line, and its hybrids Jinyou 402 and Junyou 207 through marker-assisted selection (MAS). The improved lines carrying one, two, and three genes were assessed for their resistance to rice blast using natural inoculation techniques in a disease nursery. Results of the study showed that better rice blast resistance was exhibited by the lines with more resistance genes.

The three genes showed strong dosage effect on rice blast resistance in hybrid background under field condition, thus effective for breeding blast resistant hybrids. The team also observed the agronomic traits of the improved lines. It was found that the improved lines were taller than or similar to controls, and no indications of disease stress were found.

Read the abstract at http://www.springerlink.com/content/q6872j37005246m6/.