Germination of radish seeds under adverse temperatures

Abstract

The temperature markedly influences seed germination and seedlings emergence of cultivated species. Thus, an experiment was carried out aiming to  evaluate the adverse effect of temperature on the germination of radish seeds (Raphanus sativus L). A completely randomized design was used, with a
factorial scheme 5 x 3 + 1, consisting of five cultivars, three temperatures and an additional treatment with emergency in substrate under greenhouse conditions, with four replications of 50 seeds. Seeds of the cultivars ‘Sparkler’, ‘Saxa’, ‘Branco Comprido’, ‘Gigante Siculo’ e ‘Vermelho Comprido’ were used. The seeds were evaluated in relation to moisture content, first count germination, primary root length, germination at 20 °C and under adverse conditions of 10 and 35 °C, and seedlings emergence. The radish seeds were not affected by adverse temperatures and showed satisfactory germination (above 90%) at temperatures ranging from 10 to 35 ºC. However, high temperatures (35 °C) negatively influenced the germination of the cultivars ‘Branco Comprido’ and ‘Vermelho Comprido’, and affected the root system development of seedlings. The seeds planted in substrate under greenhouse conditions, at average temperature of 25 ºC, showed germination greater than 93%, reflecting the vigour of the cultivars lots used in the study.