Inheritance of Phytosterol Content in Tobacco1
- Asep Tojib,
- D. L. Davis and
- P. D. Legg2
The pattern of sterol concentration and estimates of combining ability effects were studied in seven selected tobacco (Nicotiana tabacum L.) genotypes. Data for total sterols and individual sterols in air-cured laminae were obtained from the parental genotypes and all possible crosses among the genotypes.
Total sterol contents of the genotypes ranged from 1.46 to 2.34 mg/g dry weight. Stigmasterol had the highest concentration of the four sterols in four of seven lines, while in the other three lines, sitosterol was predominant. The cumulative total of stigmasterol and sitosterol accounted for about 70% of the total sterol. Cholesterol was present in the least amount, followed by campesterol.
With the exception of cholesterol, average heterosis was less than 2% and nonsignificant. The analysis of combining ability revealed that the variances of GCA effects for five variables (total sterol, cholesterol, campesterol, stigmasterol, and sitosterol) were significant (0.05 level). Variances of SCA effects were signiicant (0.05 level) for stigmasterol, sitosterol, and total sterols. The relative magnitudes of the GCA and SCA effects suggest that the variables were governed more by additive gene action than by dominance. The relatively low amounts of nonadditive types of gene action was substantiated by the (Wr, Vr) graphs. Breeding procedures designed to accumulate favorable alleles at all loci should be an effective means for altering sterol content.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
Copyright © . .