NATURE OF GENE ACTION FOR SOME ECONOMIC CHARACTERS OF TOMATO (Lycopersicon esculentum L.) VARIETIES

Document Type : Original Article

Abstract

Knowledge about the mode of gene action of economical traits(which directly contribute towards yield and fruit quality) in any crop liketomato (lycopersicon esculentum L.) helps to formulate the genetic basis forbreeding. Thus, the aim of the present study was to estimate different types ofgene action affecting some characteristics of tomato. For this purpose, fivetomato varieties were used. These varieties were: Advantage 2 (P1), Cherry(P2), Fatma (P3), Edkaway (P4) and Castle Rock (P5). The varieties werecrossed by using complete diallel crosses mating design, in order to produce20 hybrids. All genotypes were evaluated during two seasons for somevegetative traits, fruit characteristics and physiological traits. The data weresubjected to biometrical analysis and the obtained results revealed that themean squares of entries were highly significant for the studied traits, leadingto the further partitioning of genetic variance into its components. Thecombined data over the two seasons showed that additive genetic varianceswere higher than their corresponding values of dominance genetic variancesfor plant height and number of primary branches per plant. On the other hand,values of dominance genetic variances were higher than their correspondingvalues of additive genetic variances for leaf area, fruit characters andchemical traits. Furthermore, heritability in broad sense (h2b%) was 93.15%
for plant height, 85.32% for number of primary branches per plant, 78.68% forleaf area, -92.38% for locules number per fruit, 97.02% for firmness fruit,68.78% for Pericarp thickness, 71.62% for total soluble solids, 81.58% forascorbic acid content and 87.13% for lycopene content. However, heritabilityestimates in narrow sense (h2n%) were more less than the correspondingvalues in all studied traits, indicating that the role of non-additive geneticvariance in the genetic expression of these traits are non-negligible. Thesegenetic parameters could be used in carrying out breeding programs suitablefor Tomato.