Intra-line uniformity and inter-line variability of doubled haploid rice lines under different environmental conditions

Abstract

Doubled haploid technology is a valuable tool in plant breeding as it shortens the breeding cycle, fixes agronomic traits in homozygous state and enhances selection efficiency of useful recessive agronomic traits. However, successful adoption of doubled haploid (DH) technology for generating useful breeding material depends on intra-line uniformity and inter-line variability for agro-morphological traits. Therefore, the major emphasis of this study has been to assess these two aspects in DH population developed from F1 anthers of KRH4 rice hybrid. The developed DH lines were evaluated for agro-morphological traits to assess the uniformity of traits within and variability between the DH lines based on Z value and on the analysis of variance test respectively. The results of the experiment indicated that, the agronomic traits were indeed uniform within but different across DH lines. A wide and significant variation was observed among the DH lines for several growth and yield attributing traits. To confirm the uniformity and stability of the traits, selected DH lines were characterized in different seasons and growing conditions. The results showed a strong positive correlation in the agronomic traits within the lines under different seasons and also in contrasting environments. Further, the SSR marker analysis revealed that the DH lines are homozygous and stable across generations. From the study, it can be inferred that the DH technology forms an important tool in generating completely homozygous lines that are stable across seasons, environments and over generations.