INBREEDING DEPRESSION OF TOMATO HYBRIDS (Solanum lycopersicum L.) DERIVED FROM PROGENITORS WITH DIFFERENT DEGREE OF DOMESTICATION

Abstract

In Mexico, the tomato (Solanum lycopersicum L.) breeding programs are developed by transnational companies, so the seeds of commercial varieties available in the national market are imported, which makes them expensive, since they are quoted in dollars or euros. The objectives of this study were: i) to evaluate fruit quality characteristics and hybrids performance, and ii) to estimate the effects of inbreeding depression on the F₂ generation. During the evaluation, a total of 23 hybrids (F₁), obtained from the crossing between 9 advanced lines S5 of native tomato and three S5 saladette lines advanced from commercial hybrids, were evaluated, as well as their respective generations F₂ and a commercial control. The experiment was performed in the 2016 in the greenhouses of the Colegio de Postgraduados Campus Montecillo, in Texcoco, Estado de Mexico. We performed a variance analysis and a means comparison using the Tukey test (P?0.05), and a contrast analysis to compare the averages of the F₁ vs. F₂. Inbreeding depression (DEP, in %) was estimated using (F₁-F₂)/F₁*-1. The analysis of variance showed significant differences for all variables between the F₁ and F₂ generations for 23 tomato crosses. The values of inbreeding depression in total fruit weight ranged from 0 to 28.6%. The crosses as LOR85 * L, LOR103 * L, LOR95 * L, had values of 68.2%, 3.1% and 3.6% respectively, exceeding F₁. For days to maturation only eight crosses had a percentage reduction in their F₂, while the rest of the crosses their F₂ exceeded their F₁. Intervarietal crosses can be a viable alternative for tomato production for small and medium producers since they show a low inbreeding depression in quality and yield characteristics.