Estimation of genetic variability, correlation and path coefficient analysis in local landraces of rice (Oryza sativa L.) for the improvement of salinity tolerance

Abstract

Twenty eight local rice landraces were assessed for eleven morphological traits for the improvement of salt tolerance ability of rice genotypes. Genotypic variance (σ 2 g), phenotypic variance (σ 2 p), phenotypic co-variance (PCV), genotypic co-variance (GCV), heritability, genetic advance, genetic advance as a percentage of mean, correlation coefficient and path coefficient were estimated. For all the traits, PCV was higher than the GCV indicating that they were controlled by non-additive gene action and selection for the improvement of these traits would be promising. Among the traits, survival rate of plant exhibited high estimates of PCV (460.72) and GCV (324.73) indicated wide range of variability for these traits where lowest phenotypic coefficient of variation (PCV) and genotypic coefficient of variation (GCV) where low PCV and GCV were observed for root dry weight (0.17 & 0.12) followed by shoot dry weight (0.31 & 0.16) and total number of roots (0.61 & 0.34) indicating lack of inherent variability and limited scope for improvement through selection for these traits among the genotypes. Highest heritability had observed in all traits except chlorophyll content and root length and maximum value of heritability was noticed for shoot length (75.96%). High heritability along with high genetic advance was noticed for survival rate of plant (31.14%) followed by live leaves percentage (11.98) and the lowest genetic advance was found in root dry weight (0.58) and shoot dry weight (0.58). Correlation study revealed that significant negative correlations at both phenotypic and genotypic level exist between standard evaluation score (SES) and survival rate (%), root length, shoot length, root fresh weight, root dry weight and shoot dry weight at the seedling stage further confirmed the importance of these parameters as useful selection criteria for screening for salt tolerance rice genotypes. Path analysis revealed that the root length (0.487), root dry weight (0.394) and shoot dry weight (0.047) had direct positive effect on standard evaluation score at genotypic level where live leaves (%) per plant (0.168), total number of roots (0.006), chlorophyll content (0.243) and shoot fresh weight (0.102) had direct positive effect on standard evaluation score at phenotypic level. From the correlation and path analysis it can be concluded that root length, root dry weight and shoot dry weight would be more promising for the improvement of salt tolerance in rice genotypes.

Genetic Mapping to Detect Stringent QTLs Using 1k-RiCA SNP Genotyping Platform from the New Landrace Associated with Salt Tolerance at the Seedling Stage in Rice

“…Different independent traits, such as survival, shoot length, shoot dry weight, root length, SPAD value, Na + concentration, K + concentration, and Na + /K + ratio, directly and indirectly contributed to the salt tolerance (dependent trait). Thus, the total salt tolerance is the sum of these eight characteristics and includes a residual effect (R), which is consistent with earlier research [ 55 , 56 , 57 , 58 , 59 ]. A path coefficient analysis revealed that survival, Na + concentration, K + concentration, and Na + /K + ratio are the most crucial features for estimating the degree of salt tolerance, as these variables collectively account for the majority of phenotypic variance.…”

Correlation coefficient and path analysis of yield and yield attributing characters of rice (Oryza sativa L.) genotypes under reproductive drought stress in the Terai region of Nepal

“…In contrast, the research we have conducted does not support the idea by Augustina et al (2013) that panicle length and grain yield are negatively correlated. Additionally, the scientist discovered a weak and positive correlation between plant height and grain yield as well as a weakly significant correlation between days to 50% heading and grain yield, all of which are similar to our findings (Rasel et al, 2018). However, there was a slight and substantial negative significant correlation between panicle weight (r=-0.096) and thousand-grain weight (r=-0.192) with grain yield.…”

Physiological and agronomical evaluation of elite rice varieties for adaptation to heat stress

“…This finding is consistent with previous reports on rice [ 39 ]. According to [ 40 ], the coefficients of phenotypic variation are low below 11%, moderate between 11 and 20%, and high above 20%. The coefficient of phenotypic variation was higher than the coefficient of genotypic variation for all traits.…”