Agronomic performance of F2 populations from tomato hybrids (Solanum lycopersicum L.)

Most tomato (Solanum lycopersicum L.) seed used in commercial in Mexico crops are acquired from foreign companies; this seed is very expensive. To avoid the expense, smaller farmers try sowing hybrid seeds from early generations (F-2 and F-3), possibly losing fruit yield and fruit quality. This work evaluated fruit yield per plant (PTF), yield components and some quality related traits of seven Saladette tomato hybrids of indeterminate growth and their respective F-2 generations. A randomized completely block design with four replications was employed in plants grown under greenhouse and hydroponic conditions. The analysis of variance of contrasts of averages between F-1 vs. F-2 detected significant differences for the variable PTF in five out of the seven genotypes ('Sun 7705' 'Moctezuma' 'Cuauhtemoc' 'Reserva' y 'Cid'). In the case of the other two genotypes ('Loreto' and 'Espartaco'), the differences were not significant, thus indicating that the reduction of fruit yield in F-2 generations was minimal. These results suggest that inbreeding depression in an F-2 generation depends particularly on the genetic constitution of the lines that formed the commercial hybrid. For total fruit number, total soluble solids content, fruit firmness, length and pH, in a general way and for the majority of the genotypes, there were no statistical differences between the averages of the F-1 and F-2 generations. These findings show that the magnitude of these characteristics remained without change in F-2 segregating individuals, some of them being quality related traits.