In groundnut (Arachis hypogaea L.) the vegetative morphology is used to determine the crop duration, maturity index and is the backbone of taxonomic classification considering the geocarpic pegging nature of the crop. Induced mutation has proved to be very beneficial in groundnut crop. In a mutation breeding program, selection of appropriate mutagen allows production of wide spectrum of desirable mutants. The present study was conducted to study the mutagenic frequency of vegetative traits appearing in M2 population of treated groundnut varieties and study the effect of different doses of chemical mutagens i.e ethyl methane sulfonate (EMS) and sodium azide (SA) in producing aberration in vegetative traits. The occurrence of segregants in M2 allows to study the variation of characters present in the parent population and selection of true mutants. As most of the characters in groundnut are not linked, it alsoallowsthe use of mutants for a varietal development.A diverse range of viable mutations with altered vegetative morphological traits were isolated in the mutagenized groundnut population in M2 generation, which may be useful in yield improvement traits. Most number of dwarf plants (147) were obtained from V3 treated with SA (V3N). Shift in the pattern of growth habit were observedin some mutants. Variation in leaflet number and size followed an order of V3>V4>V1>V2. Cuneate mutant was observed in V1. V4 had unique trait of leaf node pigmentation. The mutagenic frequency ranged from 0.0484 in V4(Total EMS to 0.5308 in V3(Total SA). SA efficiently produced more number of mutants than EMS. In growth habit erect type was prominent mutant. In number of leaflets, pentafoliate and hexafoliate types and in leaf tip the mucronate mutant were most common type of mutation in segregating plant population. In mutation breeding experiment handling and maintaining of the field is a challenging task. Generally, the morphological mutants are not taken into consideration to estimate the mutagenic frequency and even if attempt is made only few desirable ones are recorded. Identification of a mutant was carried out with the set of groundnut descriptors to study the variations occurring and further generation screening and advancement.

Segregation, mutagenic frequency, aberration, mutation, Arachis

A wide range of mutations (aberrations) were observed in the vegetative traits in M2 population. A total of 276 dwarf mutants were observed and 823 number of leaf anomaly mutants recorded in the entire population. The mutation frequency of SA treated plants in every variety was higher than the EMS treated population for inducing mutants in vegetative traits. The percentage of mutants occurring was 2.667 which refers to single event of individual mutant considered at a time, but there is a chance of overlapping of two or more mutant traits in a single plant which further decreases the actual number of mutant. V3 responded very well to SA. plants in the population. This is an important consideration to make while studying the mutant population for individual traits and forwarding the population to next generation. It is to be noted that mutants for vegetative traits help study the effect of different mutagenic doses and developing any uniquemutant into a new variety either directly or in subsequent generations. As vegetative traits are qualitative traits and not affected by environment these do not need stringent methods as pod yield contributing characters. The mutants, mainly dwarf types and early maturing types were forwarded to M3 generation for yield studies and character stability.

Plawani Panda and Banshidhar Pradhan (2022). Segregation of Vegetative Trait Aberrations in Chemical Mutagen Treated Groundnut (Arachis hypogaea L.) Varieties. Biological Forum – An International Journal, 14(4a): 291-296.