Philippine E-Journals

Phenotypic and Genotypic Mutations in Cowpea Bukal Variety (Vigna unguiculata, Walp) Induced with Gamma Radiation

Jhoanna B. Calubaquib

 

Abstract:

Mutation Breeding through Gamma Irradiation is a potential technique to induce mutation for crop improvement. The study was done to induce phenotypic and genotypic variations in Vigna unguiculata using radiation doses expressed in Gray of the Cobalt60 Gamma Chamber. Cytogenetic analysis and irradiation were conducted in Manila while field testing was undertaken in Cagayan, Philippines. Chromosome assay in anaphase cells revealed that the G1 (100Gy) cells exhibited interlocking chromosomes. G2 (150) cells showed parallel chromosome segments. G3 (200) and G4 (250) cells exuded double bridges and criss-crosses of chromosome segments, respectively. Under anaphase I, G5 (300) cells exhibited ringed chromosomes and breakages from the centromeres, while G5 anaphase II showed double bridges. Results of phenotypic evaluation indicated that all the yield-contributing mutants such as heavier pod, longer pod, increased number of seeds and green pods were consistently induced by doses -200, 100 and 300 Grays. The most effective dose to induce desirable traits was the 200 Gy. Qualitative mutants like pod and seed coat colors were manifested in all the samples. The quantitative phenotypic mutants developed in M1 and M2 progenies were all considered beneficial traits and majority of these showed considerable improvement in the second mutagenic (M2) generation.