Variability and genetic diversity study in an advanced segregating population of rice with bacterial blight resistance genes introgressed

Abstract

Bacterial blight disease of rice caused by Xanthomonas oryzae pv. oryzae is one of the most important widespread disease around the globe and can cause severe yield reductions of up to 30% of the total yield. Genetic variability was studied in 54 families of CB 174 R × IRBB 60 rice with bacterial blight resistance genes introgressed at the Department of Rice, Tamil Nadu Agricultural University, Coimbatore, India. Traits such as plant height and the number of productive tillers per plant were found to have negative skewness in this study, indicating the duplication of gene effects. Panicle length and the number of grains per panicle were found to have positive kurtosis, indicating gene interactions. The phenotypic coefficient of variation was slightly higher than the genotypic coefficient of variation for all traits, indicating that the observed variation was not only due to genotypic but also due to the environmental effect on the expression of these traits. High heritability coupled with high genetic advance as a percent of the mean was observed for plant height. Moreover, moderate heritability coupled with high genetic advance as a percent of the mean was observed for the single plant yield of rice. Cluster and principal component analyses revealed that the 54 F2:3 families were grouped into three clusters based on six agro-morphological traits. Clusters III and II had higher mean values for most of the studied traits than cluster I. Intercrossing lines from distinct clusters can be identified and crossed to generate larger variability to produce desirable recombinants for higher yield with a wide genetic base.

Exploring the Relationship between Yield and Yield Attributing Traits in Advanced Breeding Lines of Rice (Oryza sativa L.)

“…Heritability estimates for different traits ranged from 21 per cent to 84.2 per cent, while as genetic advance as per cent of mean ranged from 5.31 per cent to 39.52 per cent. Govintharaj et al, [10]; Adhikhari et al, [11] and Dhavaleshvar et al, [12] also found similar results in their research findings. Traits viz., total number of tillers per plant, number of effective (productive) tillers per plant, grain yield per plant and grain yield per plot were found to have high genetic advance (GAM) coupled with high heritability implying that these traits have been efficiently inherited from generation to generation.…”

Agro-morphological and Genotypic Diversity among Rice Germplasms under Rainfed Lowland Condition

“…In accord with our findings, grain yield was reported for a higher phenotypic and genotypic coefficient of variation by several researchers. These researchers also find phenotypic components higher over genotypic components of variation in the studied traits (Abebe, Alamerew, & Tulu, 2017;Adhikari, Joshi, Shrestha, & Bhatta, 2018;Govintharaj, Manonmani, & Robin, 2018;Kishore, Srinivas, Nagabhushanam, Pallavi, & Sameera, 2015;Tiwari, Tripathi, Tripathi, Khatri, & Bastola, 2019). Broad sense heritability values were recorded highest for DTF (97.40%), DTM (91.78%), PHT (86.62%), HI (87.17%), and TGW (71.06%) whereas found moderate for PL (63.22%), BY (47.45%), and GY (64.26%) respectively.…”

Effect of selection response for yield related traits in early and later generations of groundnut (Arachis hypogaea L.)

“…The study of distribution using skewness and kurtosis provides information about the nature of gene action and the number of genes controlling the traits (Govintharaj et al 2018). Positive skewness is associated with complementary gene action, while negative skewness is associated with duplicate (additive × additive) gene interactions.…”