ABSTRACT
The objective of this study was to evaluate the phyllochron and the thermal requirement of Italian tomato hybrids in different phenological phases and different cycles of cultivation. The experiments were carried out in the experimental area of the Federal University of Santa Maria campus Frederico Westphalen, Rio Grande do Sul State, Brazil, in the years 2012 and 2013. The experimental design was a randomized block 2x2x5, with two tomato hybrids, two crop cycles and five phenological stages, with four replications. Hybrids San Vito and Neptune were evaluated, with indeterminate growth habit, during winter-spring and summer-autumn. Thermal needs for each phenological phase was calculated by the accumulation of temperature throughout each phase. Hybrid San Vito showed a phyllochron superior to Neptune in the winter-spring, but, both were similar in summer-autumn. The total thermal requirement for the winter-spring crop was 1749.4 and 1717.5 degrees days for San Vito and Neptune hybrids and 1534.6 and 1495.2 degrees days in the summer-autumn, respectively. Neptune hybrid was earlier and presented a longer production period. In the winter-spring cycle, the highest thermal requirement occurred in fruit maturation phase, while in the summer-fall, the highest thermal requirement occurred in the vegetative growth stage. During summer-autumn, the cycle of both hybrids was shorter, with early production and concentrated fruiting period.
Keywords:
Solanum lycopersicum; stage; leaf emission; temperature; solar radiation; season
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