Cyto-sensitivity of some locally grown pigeon pea [cajanus cajan (l.) millsp] to amiprophos methyl treatment as a guide for improvement

Effects of mutagens on the chromosomes of crop plants are a good indicator to deciphering the extent to which they can be utilized for crop improvement. The aim of this research work was to evaluate the cyto-sensitivity of two landraces of pigeon pea [Cajanus cajan (L.) Millsp] to amiprophos methyl (APM). The seeds from the two varieties were soaked in different concentrations of APM (4ppm, 6ppm and 8ppm) for 24, 48 and 72 hours, respectively. From the control experiment, it was observed that the diploid chromosome number was 2n=22. This diploid was also observed in other treated cells not affected by the APM treatment. The APM treatment caused varying types of chromosomal aberrations or abnormalities, which was observed to be concentration and time – dependent. The following chromosome abnormalities were observed viz,; disoriented chromosomes, clumped chromosome, laggards, sticky chromosomes, irregular chromosomes with bridges, inhibited chromosomes, elongated chromosomes, curved chromosomes; thick and sticky chromosomes. Chromosome doubling (polyploidy; 4n = 44) was also observed in seeds of brown pigeon pea treated with 6ppm of AMP for 24 hours; 6ppm of AMP for 48 hours and 8ppm of AMP for 48 hours for the white variety, respectively. Our result also revealed that the total percentage chromosomal aberrations increased with increase in the concentration of the mutagen and majorly on the duration of soaking, the variety notwithstanding. Succinctly, the chromosomal aberrations caused by the treatment of the seeds with amiprophos methyl (APM) notwithstanding, the induction of polyploidy to these pigeon pea landraces is significant in crop breeding and improvement if meticulously exploited.