Genetic variability for quantitative characters among commercial varieties of sugar beet (Beta vulgaris L.)

Includes references.

Twenty six sugar beet (Beta vulgaris L.) varieties introduced from different countries were used in this investigation during three successive seasons of (2002- 2003 and 2004), at three different locations (Nubari8- Kafr EI Sheik and Fayum). The main objectives of this study were to determine variance components for the important characters as root and sugar yields. Root yield, in particular, is a complex character dependent on many simpler components of varieties x environment interaction which were apparent in the rankings of the cultivars in the nine environments examined. Two varieties namely, H. poly and kawernena poly, were the highest yielding, 41.9 and 40.22 ton /fed, respectively for root yield. Sugar yield /s the most important characters for the present study. Cultivar H. poly was the highest and Mezano poly was the lowest during three seasons at three locations where averages of sugar yield were 6.68 and-2.65 ton/fed respectively. The present investigation was carried out to study the relationship between various morphological and economic traits in sugar beet. Data were recorded on characters associations in sugar beet as root length, root width, top weight, crown size, root number, root yield / plot, root weight and total soluble solids percentage. The object was also subjected to study some biometrical parameters as the range, genotypic and phenotypic variance, genotypic and phenotypic coefficient of variability, heritability percentage and genetic advance percent of mean for the important characters of sugar yield component. The genetic variance calculated for the different characters was essential in determining the phenotypic variance, which ranged from 0.325 for root weight to 732.61 for yield/plot. The variance due to the interaction of genotype x environment was secondary to genetic variance, while the variance due to error was the smallest part of the phenotypic variance. Coefficient of variability percentage estimates was the lowest for total soluble solids and the highest for root weigh Heritability in broad sense estimates ranged from 22% for root yield to 96% for total soluble solids. Genetic advance percent was high for sugar yield ton/fed (71%), root weight /kg (46.5%) and yield /plot/kg (38.26%) while it was lowest for top weight (10.4%) and total soluble solids (13.13%).

Summary in Arabic.

1