HETEROSIS IN CROSSES AMONG BELL PEPPER-SHAPED MEXICAN NATIVE TOMATO (Solanum lycopersicum L.) LINES AND SALADETTE TYPE LINES

Abstract

Tomato (Solanum lycopersicum L.) is one of the most important vegetables cultivated in México due to its cultivated surface, its commodity status, the number of jobs required for production, and its nutritional and cultural value. However, little is known about the native Mexican landraces in terms of yield performance, fruit quality, resistance to biotic and abiotic factors, and their potential as a source of germplasm for plant breeding programs. In this work, heterotic performance of 40 crosses formed among 10 S5 lines derived from Mexican native tomato pepper type accessions, locally called “Chino Criollo”, and four S5 lines originated from commercial hybrids of “saladette” type was evaluated. The experiment was carried out under greenhouse and hydroponics conditions, in a randomized complete block design with three replications and five plants per replication. Traits evaluated were total weight of fruit (PTF), average fruit weight (PPF), total number of fruits (NTF), fruit firmness (FF), number of flowers in the third cluster (NFR3), number of clusters per plant (NRP), and days to flowering in the first cluster (DF1). There were significant differences (P ≤ 0.01) between genotypes, crosses, lines and groups of genetic materials for most variables. The cross with the highest yield was LOR111R with 3624 g/plant, followed by the control variety El Cid, with 3452 g/plant. For traits PPF, NTF and NRP, there were some crosses that at least equaled and in some cases exceeded the values of the hybrid control variety. Positive values for mean heterosis were obtained in most variables, except for days to flowering. For fruit yield the mean heterosis ranged from -21.8. to 111.2 %, whereas for PPF it was -13 to 80.7 %. Results for the per se performance of the lines and their crosses show great genetic divergence among native genetic materials, which was reflected in high yields and high mean heterosis that can be exploited in tomato breeding programs.