Inoculação de Fusarium moniliforme (Sheld.) em sementes de duas cultivares de pepino através da técnica da restrição hídrica e sua influência sobre a qualidade fisiológica.

Abstract

The cucumber (Cucumis sativus L.) is a vegetable belonging to the family Cucurbitaceae, of great importance in Brazil. It is grown, preferentially in tropical climate, in high temperature conditions. It has a high economical, nourishing and social value because it generates direct or indirect jobs, requiring a labor demand from its cultivation to its commercialization. Due to the cultivation expression, the seed physiological and sanitary quality constitutes an important factor, being responsible for limitations in the product quality which is addressed to commercialization. So, with this work, one aimed at verifying the influence of Fusarium moniliforme on the seed physiological quality of two cucumber cultivars: Wisconsin and Caipira, through the hydric restriction inoculation technique, besides assessing the efficiency of the vigor tests for the stratification of the lots according to its physiological quality. The isolate of F. moniliforme was obtained from cucumber seeds. Each cultivar was divided into three lots of different physiological quality, differentiated by artificial aging. The treatments consisted in: Absolute witness; PDA + mannitol 0.8 Mpa; PDA pure; PDA + mannitol 0.8 Mpa + F.moniliforme; and PDA + F. moniliforme. The seed physiological quality was evaluated through tests carried out in laboratory conditions and in greenhouse. The hydric restraint was efficient to infect the seeds of two cultivars by pathogen, proving that this influences negatively in physiological quality of them and it can be transmitted by these. For cultivar Wisconsin, the tests of germination, cold and seedling growth were sensible to the lot stratification in two physiological levels. In the emergence of plants the speed emergence index, the root length and dry matter were able to classify the lots in three physiological categories. For the cultivar Caipira, the tests of germination and cold stratified the lots in two levels of vigor. In the test of growth of seedlings, the length of hypocotyls and root presented sensitivity to the classification of the lots in three physiological levels. For the plant emergence, the length of the hypocotyls and root and, dry matter showed themselves apt to the lot classification according to the physiological quality of them.