Identification of heat-tolerant rice genotypes and their molecular characterisation using SSR markers

Abstract

The effect of high-temperature stress has a critical impact in causing reduced crop yield. The focus of the current investigation is the identification of heat-tolerant rice varieties that can alleviate the effects of stress. Among the ten genotypes evaluated across various parameters such as leaf area, dry weight, photosynthetic rate, stomatal conductance and spikelet fertility, N-22 showed superior characteristics for the grain filling parameters along with CR-Dhan 307. The variety CR-Dhan 307 with significantly higher mean pollen viability (80.23%), spikelet fertility (81.18%) and 1000 grain weight (25.45 gm) can be utilized as a heat-tolerant variety. Other genotypes Ptb-7 and CR-Dhan 202 seemed to have tolerance traits beneficial at the vegetative stage. The genotype Rajalakshmi can be characterised as heat susceptible as it had significantly lower values for all parameters. Polymorphic analysis was carried out to validate SSR markers associated with heat tolerance. The polymorphic information content (PIC) was found to be the highest for RM236 and RM6100. The SSR marker RM6100 has been validated in the current investigation to be associated with heat tolerance. As the PIC value is an indication of the ability of the marker in indicating genetic diversity, the PIC values of the 11 polymorphic markers is useful for identify heat-tolerant genotypes. The genetic diversity analysis was carried out using DendroUPGMA to establish the relationship between the genotypes. The genotypes Ptb-7 and CR-Dhan 204 were thus found to be closely related to the heat-tolerant check variety, N-22 indicating genetically related traits for tolerance to heat.

Identification of simple sequence repeat markers linked to heat tolerance in rice using bulked segregant analysis in F2 population of NERICA-L 44 × Uma

“…(2014) , in their study, found association between RM6100 and a major quantitative trait locus affecting tolerance to heat stress at the flowering stage. The association of RM6100 with high temperature tolerance in rice was also reported by Stephen et al. (2022a) .…”

“…Bharathkumar et al (2014), in their study, found association between RM6100 and a major quantitative trait locus affecting tolerance to heat stress at the flowering stage. The association of RM6100 with high temperature tolerance in rice was also reported by Stephen et al (2022a). Revathi et al (2013) reported that RM6100 linked to the fertility restoration gene, Rf4, had 85% efficiency in identifying restoration lines in rice.…”

Population Structure Analysis and Marker Trait Association in Traditional Rice (Oryza sativa L.) Landraces of Kerala under High Temperature Condition

“…Number of lled grains under high temperature condition was found to be drastically decreased Julia and Dingkuhn (2013). andStephen et al, (2022b) found similar results that the decrease in fertile pollen grains on the stigma might result in the decrease in grain number in each panicle. Number of un lled grains under high temperature condition was found to be increased.…”