Phenotypic characterization and genetic analysis of dwarf and early flowering mutants of rice variety Nagina22

Plant height and flowering time are two of the important traits that affect plant architecture. Efforts were made in this study to characterize morphologically the-EMS-induced dwarf and early flowering mutants of rice variety Nagina22 and to study their mode of inheritance. Nine true breeding mutants generated earlier by EMS treatment were analysed for differences in their phenotypic characteristics recorded according to the national guidelines for Distinctness, Uniformity and Stability (DUS). The mutants exhibited variation from Nagina22 for maximum of 11 DUS characteristics to a minimum of 4 DUS descriptors, while retaining majority of the wild type features. Plant height of the dwarf mutants ranged from 69 to 101cm, while tiller number was in the range of 9 to 60. The early flowering mutants were weak in their plant stature, but flowered approximately 20-25 days earlier than Nagina22. Significant correlation among various traits of the selected mutants was observed. The mutant traits exhibited monogenic inheritance giving 3:1 phenotypic segregation ratio in F2 generation. These mutants have potential usage in functional analysis of the traits and in rice improvement programs.