Influência de diferentes posições de sementes sobre o crescimento de plântulas de Citrullus lanatus (Thunb.) Matsum. & Nakai.

Abstract

Citrullus lanatus (Thunb.) Matsum. & Nakai is one of the most widely cultivated fruit vegetables in the world and has great agricultural importance in Brazil, especially in Bahia, the largest producing state. The production and productivity of this crop are influenced by the physiological potential of the seeds, framed within the overall value of the lot. Germination and vigor are two attributes of physiological potential and can influence the uniformity of emergence and the initial development of seedlings in the field. Although the germination test is used to assess seed lot quality, it is not sufficient to predict their performance under unfavorable conditions because it is conducted under ideal conditions, making it necessary to apply broader methodologies, such as vigor tests. The vigor of a seed lot can be measured by different tests, such as the seedling length test, which measures the main seedling structures — shoot and root — as well as by the dry matter test, which have proven effective and do not require sophisticated equipment, only standardized and well-defined methods. During the preparation of these tests, it is assumed that the position in which the seed radicle is placed in relation to the germination paper interferes with the initial seedling growth. That said, this study aimed to evaluate the influence of the radicle position of watermelon seeds on vigor, assessed through seedling length and dry matter tests. The experiment was carried out at the Seed Laboratory (LASEM) on the Umuarama campus of the Federal University of Uberlândia (UFU), in a randomized block design, with a 3x3 factorial scheme, the first factor being the three positions (position 1: radicle downward; position 2: radicle horizontal; position 3: radicle upward), and the second factor being three lots of watermelon seeds (lots 16789926, 16789943 and 16789897), totaling 9 treatments, with 4 replications. After 10 days in the germinator, the seedlings were classified as strong and weak, then the shoot and root parts were measured, dissected into cotyledons, hypocotyl and radicle, dried in an oven and finally weighed on a precision scale. The data obtained were subjected to analysis of variance and to Tukey’s mean comparison test at 5% significance. The results confirmed the hypothesis that position can influence seedling vigor, with position 1 being the most suitable and position 3 an alternative.