Molecular breeding for the development of multiple disease resistance in Basmati rice

Karmakar

Plant Biotechnology Journal

et al. 2020

191

163

Summary Rice sheath blight disease, caused by the basidiomycetous necrotroph Rhizoctonia solani, became one of the major threats to the rice cultivation worldwide, especially after the adoption of high‐yielding varieties. The pathogen is challenging to manage because of its extensively broad host range and high genetic variability and also due to the inability to find any satisfactory level of natural resistance from the available rice germplasm. It is high time to find remedies to combat the pathogen for reducing rice yield losses and subsequently to minimize the threat to global food security. The development of genetic resistance is one of the alternative means to avoid the use of hazardous chemical fungicides. This review mainly focuses on the effort of better understanding the host–pathogen relationship, finding the gene loci/markers imparting resistance response and modifying the host genome through transgenic development. The latest development and trend in the R. solani–rice pathosystem research with gap analysis are provided.

Section: Quantitative Trait Loci (Qtl)‐based Resistancementioning

confidence: 99%

Understanding sheath blight resistance in rice: the road behind and the road ahead

Karmakar

Plant Biotechnology Journal

et al. 2020

191

163

Australasian Plant Pathol.

“…Two-gene model for blast resistance was studied by categorizing as resistant, moderately resistant, moderately susceptible and susceptible. The plant disease reaction was categorized according to Singh et al (2012) with minor modification. Plants expressing lesion with the score 0-2 were considered as resistant, 3 as moderately resistant, 4-6 as moderately susceptible, and 7-9 as susceptible for two-gene model.…”

Section: Evaluation Of Disease Resistancementioning

confidence: 99%

Identification of suitable segregating SSR markers for blast resistance in rice using inheritance and disease reaction analysis in backcross families

Tanweer

Rafii

Sijam

et al. 2015

The study was conducted to identify the suitable SSR markers in relation to blast disease of rice. Backcross breeding was applied and BC 2 F 1 generation was produced using rice variety Pongsu Seribu 2 as blast resistant parent and MR219 as susceptible parent. Eleven SSR markers related to blast resistance genes (Pi gene) were found highly polymorphic between the parental lines. According to single-gene model only two markers, RM208 and RM206, fitted to the expected test cross ratio (1:1) in BC 2 F 1 generation with the relation to resistant and susceptible plants. Further BC 2 F 1 population carrying 320 plants were inoculated with the highly virulent pathotype P7.2 of Magnaporthe oryze. Chi-square (χ2) test for single-gene model showed goodness of fit (p=0.45) to the expected segregation ratio (1:1) for phenotypic segregation in BC 2 F 1 population. In marker segregation analysis two markers RM208 (χ2=1.513, p=0.218) and RM206 (χ2=0.613, P=0.433) clearly produced goodness of fit to the expected test cross ratio (1:1) for the single-gene model. The present finding could help the rice breeders to monitor the blast resistance genes with appropriate and highly segregating SSR markers in rice varietal development program against blast disease.

“…In the case of single-gene model analysis, the rice plants showing lesion types 0 to 3 were considered as resistant and the plants showing lesions type 4 and above were considered to be susceptible to the selected pathotype P7.2 in BC 2 F 1 population. Plant disease reaction was categorized according to Singh et al (2012) with some modification.…”

Section: Methodsmentioning

confidence: 99%

Inheritance patterns and identification of microsatellite markers linked to the rice blast resistance in BC2F1 population of rice breeding

et al. 2015

The BC 2 F 1 population was derived from a cross between rice variety, MR219 (susceptible to blast) and Pongsu Seribu 1 (resistant to blast). The objectives of this research were to know the inheritance pattern of blast resistance and to identify the linked markers associated with blast resistance in BC 2 F 1 population. Sixteen microsatellite markers were found as polymorphic between the parents related to blast resistant genes (Pi-genes). Among the selected blast resistant linked markers, two markers RM6836 and RM8225 showed expected testcross ratio (1:1) for single-gene model in the BC 2 F 1 population with the association between resistant and susceptible progeny. A total of 333-BC 2 F 1 plants were challenged with the most virulent pathotype P7.2 of Magnaporthe oryzae. Chi-square (χ 2 ) analysis for phenotypic segregation in single-gene model showed goodness of fit (P = 0.4463) to the expected segregation ratio (1:1). In marker segregation analysis, two polymorphic markers (RM6836 and RM8225) clearly showed goodness of fit to the expected segregation testcross ratio (1:1) for the single-gene model. The marker RM8225 and RM6836 showed significant R 2 values higher than 10 for the trait of the blast lesions degree (BLD). The positions of RM6836 and RM8225 markers on rice chromosome 6 and the distance between these two markers is 0.2 cM. We conclude that single dominant gene control the blast resistance in Pongsu Seribu 1 located on chromosome 6, which is linked to RM8225 and RM6836 microsatellite markers. This information could be useful in marker-assisted selection for blast resistance in rice breeding involving Pongsu Seribu 1.