Heterosis, potence ratio and correlation of some important characters in tomato (Solanum lycopersicum L.)

Five commercial tomato (Solanum lycopersicum L.) cultivars and their ten F-1 hybrids were used in order to detect the general performances and estimation the heterosis percentages, potence ratios, and phenotypic correlation coefficients among all possible pairs of some important tomato's characters. The obtained results reflected a range of significant variability for most of the traits studied. The general performances of the F-1 hybrids reflected the presence of various degrees of dominance effects; i.e., partial- to over-dominance for the characters of plant height, number of primary branches per plant, pericarp thickness, fruit firmness, total soluble solids, ascorbic acid content, number of flowers per cluster, number of fruits per plant and total fruits yield per plant. Whereas, some others studied characters; i.e., fruit shape index, locules number per fruit and fruit weight, illustrated the presence of partial- to under-recessiveness; but, with different degrees. All 10 F-1 hybrids had significantly higher number of fruits per plant and total fruits yield per plant than their respective mid-parental values, meanwhile for the other traits, hybrids exhibited average heterosis in both directions. The mid-parent heterosis varied from -16.04 to 29.75% for plant height, -5.74 to 20.95 for number of primary branches per plant, -34.72 to 15.18% for fruit shape index, -35.72 to 49.02% for number of locules per fruit, -9.22 to 25.88% for pericarp thickness, -5.02 to 15.21% for fruit firmness, -11.46 to 25.50 for total soluble solids, -1.26 to 15.66% for ascorbic acid content, -9.39 to 22.48% for number of flowers per cluster, 4.37 to 104.69% for number of fruits per plant, -32.78 to 11.29% for average fruit weight, 22.29 to 64.33% for total fruits yield per plant. Significant positive correlation between total fruits yield per plant and each of the number of flowers per cluster, number of fruits per plant and average fruit weight was detected. On the other side, significant negative correlation was observed between number of fruits per plant and fruit weight. (C) 2012 Elsevier B.V. All rights reserved.