Preferential segregation of two allelic mutations for small leaf character in groundnut.

Two radiation induced small leaf mutants were isolated in a Spanish Improved variety of groundnut. Both had more than a 50% reduced leaflet size which was associated with an increased number of imparipinnate leaves in one mutant and light yellow flower colour in the other. Genetic studies demonstrated that both mutants were allelic and controlled by recessive factors. Phenotypic and genotypic segregation ratios indicated a lower frequency of mutants. This was attributed to preferential segregation in favour of normal leaf size. Marker genes controlling krinkle leaf, virescent and chlorina characters showed independent assortment in crosses with the small leaf mutants. Absence of assortment of associated mutant characters viz., small leaf and light yellow flower colour, generally indicated pleiotropic effects. However, monohybrid segregation for flower colour in the cross between the two small leaf mutants showed that the two characters were independently induced and hence attributed to close linkage and not pleiotropy.