Genetic study of some morphological characteristics in sugar beet using diallel cross analysis and GGE Biplot methodology

In order to study the mode of genetic control and heritability of morphological characteristics important for the improvement of root weight, sugar yield and white sugar yield in tropical beet, Griffing's diallel cross method along with the biplot display of diallel data were applied. Nine sugar beet lines including 7112-36, 7173, 474, 452, 261, 436-104, SB-FIROZ, RR607 and 436 were crossed in one-way diallel cross. Parental lines along with 36 consequent hybrids were implemented at Safiabad Agricultural Research Center, Dezful, Iran in 2009. The experimental design was a triple lattice with three replications. The traits root length, root diameter and crown height was measured. Analysis of variance showed significant differences among genotypes for root length and crown height at one percent and for root diameter at five percent probability levels. The highest broad-sense heritability was estimated for root length, a trait that was mainly controlled by non-additive gene effects. For root diameter and crown height, additive gene effects were found to be more important than non-additive effects. General combining ability (GCA) of genotypes was significant for all the three morphological characters at five percent probability level. The GGE bi-plot graphical analysis was used to evaluate the potential utility of the O-type lines. The parent 7173 had a positive, significant GCA for root diameter. The best hybrids for short root length, large root diameter and short crown height were 7173 × 436, 436-104 × 436 and 436 × 261, respectively.