Abstract

MENDOZA-DE JESUS, V. et al. Intervarietal heterosis in indeterminate saladette tomato. Rev. Chapingo Ser.Hortic [online]. 2010, vol.16, n.1, pp.57-66. ISSN 2007-4034.

Producing high-quality and high-yielding tomatoes (Lycopersicon esculentum Mill.) in Mexico is expensive, largely due to the high cost of seed. To contribute to solving this problem, an experiment was carried out under greenhouse and hydroponics conditions to assess the potential of saladette tomato hybrids of indeterminate growth and long shelf-life for the development of varieties with low-cost seed. Nine saladette hybrids and their 72 direct crosses were evaluated according to Griffing's design I. The 81 entries were assessed in a randomized complete block design with four replications. Results showed significance (P≤0.01) of the mean squares for general (GCA) and specific combining ability (SCA) effects for all measured variables except for shelf life (SL) and plant height, but significance (P≤0.05) was not found for maternal and reciprocal effects in any case. However, six crosses that involved at least one of the top five hybrids for fruit yield equaled the SL of their parents (P≤0.05) and showed heterotic effects with respect to the best and mean parent that ranged from 9 to 11 and 7 to 17 kg of fruit per experimental unit of eight plants, respectively (P≤0.01 or P≤0.05). This information suggests that these crosses should be cheap and economically successful for the producer. The fruit yield heterotic effects were related to those for total fruit number and number of fruits per cluster which were also significant (P≤0.01 or P≤0.05). In addition, one hybrid, which showed the largest effect of GCA and mean for fruit yield, can be used in a breeding program designed to exploit the additive gene action.

Keywords : yield components; general combining ability; specific combining ability; Lycopersicon esculentum Mill.