Crescimento de genótipos de tomateiro sob deficiência hídrica

Abstract

The tomato has great importance in the national and international scenario, presenting great production and commercial movement. Water deficiency affects the development of the crop and negatively interferes in fruit productivity and quality, its effects can be aggravated when the temperature conditions are high and the relative humidity is low. However, the technical recommendations and / or genotypes developed exclusively for the organic production system are still incipient. The crop requires a lot of care, especially when the producer uses a cultivar not adapted to the region and the cultivation system adopted. Its cultivation is considered high risk, mainly due to its great sensitivity to a series of biotic and abiotic factors. In this way the objective of the present study was to evaluate morphological characters of tomato genotypes submitted to water deficiency, with a view to analyze the performance of f2 population from two different crosses. The experiment was conducted in the experimental area of the Federal Technological University of Paraná, Campus Pato Branco. The F2 genotypes evaluated came from the selffertilization of plants from the cross between tomatoes accesses (Access 2037 and Access 2016) belonging to the Tomato Plant Bank of UTFPR and a commercial hybrid (male parental), resulting in two combinations: Access UTFPR_2037 x Hybrid (junction 1) and Access UTFPR_2016 x Hybrid (junction 2). The design of the plants was completely randomized, being used 100 plants for each crossing. The evaluations were performed when the containers had 25% of the field capacity, being this index determined from the beginning of typical symptoms of water stress (wilt, yellowing and leaf fall) observed in the plants. The following evaluations were carried out: fresh aerial mass MFPA, aerial dry mass MSPA, fresh mass of roots MFRA, dry mass of root MSRA, root / air ratio MSRA / MSPA, number of leaves NF, height ALT and diameter of the DC cell for all genotypes from each cross. The mean values of MFPA and MSPA were higher for crossing 2 (3.62 and 1.52 g) respectively, due to the higher means found for NF (6.33 g) and DC (3.77 g). The MFRA, MSRA and MSRA / MSPA characters were larger for crossing 1 (0.63, 0.32 and 0.39 g), respectively. The mean values for the root and height characters were more significant for the population obtained from crossing 1, which may indicate a greater potential for obtaining tolerant varieties under the condition of water stress. However, although the averages for these characters are relatively higher for the population at junction 1, both populations presented selection potential for genotypes tolerant to water deficiency.