ISHS Acta Horticulturae 637: XXVI International Horticultural Congress: Advances in Vegetable Breeding
GENETIC PARAMETERS OF MEAN FRUIT WEIGHT AND THEIR COMPONENTS OF TOMATO |
| Authors: | E. Rodríguez, A. Carballo, G.A. Baca, A.G. Martinez, M.R. Rosas |
| Keywords: | Lycopersicon esculentum, breeding, fruit quality, genetic action, heritability |
| Abstract:
Tomato breeding in Mexico has been oriented to increase yield, earliness, growth habit and tolerance or resistance to environmental stresses, pests and diseases, but varieties with firm fruit and high quality are necessary. The present research determined gene action for mean fruit weight, pericarp weight and locule content weight. A complete diallel using 10 experimental lines was evaluated during Spring-Summer 1998 in a greenhouse at Lomas de Cristo, Mexico and in a non-recirculating, open hydroponic system using Steiner’s Universal solution applied via drip irrigation at 0.7 atm osmotic pressure. The experimental design was a 10 x 10 partially balanced lattice with two replications. To estimate mean fruit weight, pericarp weight and locule content weight, fruit were collected mature, weighed individually, cut equatorially to extract locule contents and fruit parts weighted separately. Genetic variance analysis was done following Griffing’s method 1. Additive genetic effects prevailed; narrow sense heritability was low, 18% to 25%. Improvement of these characters in selection requires the appropriate breeding method, using a low pressure selection index. The best parents (CJPL-8-7-4, CJPL-2-2-1) were equal in their general combining ability for the three characters studied. Mean fruit weight components permit improvement for soluble solids and fruit flavor along with increased fruit weight. Significant reciprocal effects indicated that mean fruit weight and its components were influenced by the male parent. Parents with the highest reciprocal effects estimates for crossing should be identified before initiating a selection process. An equilibrium exists between pericarp weight and locule content weight: an increase for one results in a decrease for the other. | |
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