MUTAGENIC EFFECTS OF DIETHYL SULPHATE ON CERTAIN MORPHOLOGICAL CHARACTERS OFNICOTIANA TABACUM

Abstract

Dry seed of flue-cured tobacco cultivars Hicks Broadleaf, Yellow Gold, and Canadel were soaked in a freshly mixed saturated solution of the chemical mutagen, diethyl sulphate, at 30 °C for 3 and 5 hours. All the plants with major visible aberrations were eliminated from the tests. Random plants were selected in 1965 and selfed seed was obtained. C2populations were grown in 1966 and C3in 1967.The means for plant height and for length of top and middle leaves of the C2and C3populations were smaller, and the means for number of days to flower were larger than those of the controls. The variances and the ranges of variation of all the treated populations were larger than those of the controls. The frequency distribution in the C3generation was skewed towards lateness to flower for the three cultivars. Negative and significant skewness was found for height in Hicks Broadleaf, and for height and length of the top leaves in Canadel. All the computed values for kurtosis were positive indicating a peaked curve of distribution. The difference between kurtosis values for the 5-hour treated populations and their respective controls was positive and significant in the cultivars Yellow Gold and Canadel for days to flower and for length of both top and middle leaves. Heritability in the broad sense ranged from 27 to 85%.