GENETIC PARAMETERS OF F1 AND F2 GENERATIONS FROM CROSSING Solanum lycopersicum L. × S. habrochaites LA1223

Abstract

Research on the knowledge of phenotypic variability of different genetic reservoirs and the estimation of genetic parameters are important aspects for tomato genetic improvement. Thus, this study aimed to evaluate Solanum habrochaites S. Knapp & D.M. Spooner as a source of variability to broaden the genetic base of the cultivated tomato by estimating genetic parameters in an interspecific cross with S. lycopersicum L. Four genotypes (an S8 line derived from the Loreto hybrid, the accession LA1223 of S. habrochaites and the F₁ and F₂ generations from the cross of both materials) were evaluated in a randomized complete block design with five replications, during a growing cycle under a greenhouse hydroponics production system. The type of gene action, mid-parent heterosis, inbreeding depression and narrow-sense heritability were estimated. Most of the variables exhibited partial dominance as the type of gene action. Stem diameter, plant height, total number of fruits and the fruit sugar content showed greater positive heterosis (27.32, 35.48, 43.10 and 34.76 %, respectively); therefore, they could be used to broaden the genetic base of tomato; however, yield and its components were affected to a great extent, as they were reduced 20.76 % on average in the F1 and F2 generations. Average narrow-sense heritability was low in F₁ (0.22), but in F₂ it increased to 0.30, even though the number of locules per fruit, number of flowers per cluster and total number of fruits per plant increased to 0.35, 0.61 and 0.25, respectively; this suggested the possibility of identifying transgressive segregants in later generations with allelic arrangement