Marker Assisted Breeding of Blast Resistant CA Varieties 98

Marker-assisted Breeding of Blast Resistant CA Rice Varieties - 98
Project Leader and Principal UC Investigators Pamela C. Ronald, Associate Professor, Department of Plant Pathology, University of California, Davis Dahu Chen, VPS, Department of Plant Pathology, University of California, Davis Dave Mackill, Research Geneticist, USDA-ARS, Department of Agronomy and Range Science, University of California, Davis	The goal of this project is to lay the genetic groundwork to breed blast resistance into California rice varieties. Specific objectives in 1998 were to assay the current level of blast resistance in M-202 and to develop genetic markers to assist in the breeding of resistant genes into California varieties. Different blast resistance genes display a range of resistance. In order to tap resistance sources more effectively, it is necessary to evaluate the resistance genes. Eight rice lines carrying different blast resistance genes were used in this study. Five resistance genes were introduced into the Japonica variety LTH (a Chinese variety) and three resistance genes were introduced into the Indica variety CO39. Crosses between these lines and M-202 were made in a growth chamber. Five genes conferring resistance to blast were identified in the these crosses. M-202 was susceptible to 12 different sources of blast innoculum, but the number of lesions were few. This suggests that M-202 carries partial resistance genes. Some of the F₁ plants derived in these crosses were fertile and some were almost sterile, a reflection of the incompatibility between japonica and indica types. Backcrossing with M-202 is needed to restore the fertility of progeny derived from these crosses. Further experiments will focus on developing DNA markers that can be used in marker-assisted breeding of the resistance gene.

Marker-assisted Breeding
of Blast Resistant CA Rice
Varieties - 98

Project Leader and Principal UC Investigators

Pamela C. Ronald, Associate Professor, Department of Plant Pathology, University of California, Davis

Dahu Chen, VPS, Department of Plant Pathology, University of California, Davis

Dave Mackill, Research Geneticist, USDA-ARS, Department of Agronomy and Range Science, University of California, Davis

The goal of this project is to lay the genetic groundwork to breed blast resistance into California rice varieties. Specific objectives in 1998 were to assay the current level of blast resistance in M-202 and to develop genetic markers to assist in the breeding of resistant genes into California varieties.

Different blast resistance genes display a range of resistance. In order to tap resistance sources more effectively, it is necessary to evaluate the resistance genes. Eight rice lines carrying different blast resistance genes were used in this study. Five resistance genes were introduced into the Japonica variety LTH (a Chinese variety) and three resistance genes were introduced into the Indica variety CO39. Crosses between these lines and M-202 were made in a growth chamber. Five genes conferring resistance to blast were identified in the these crosses. M-202 was susceptible to 12 different sources of blast innoculum, but the number of lesions were few. This suggests that M-202 carries partial resistance genes.

Some of the F₁ plants derived in these crosses were fertile and some were almost sterile, a reflection of the incompatibility between japonica and indica types. Backcrossing with M-202 is needed to restore the fertility of progeny derived from these crosses.

Further experiments will focus on developing DNA markers that can be used in marker-assisted breeding of the resistance gene.