Non-parametric survival analysis in seed germination of forest species

Abstract

ABSTRACT: In statistical analyses of seed germination experiments, it is essential to ensure that the assumptions of the chosen methods are not violated to obtain valid and reliable results. When these assumptions are violated, alternative methods should be considered, one of which is survival analysis. This study aimed to evaluate the application of this methodology, using a nonparametric approach, to assess the germination of Cecropia pachystachya and Jacaranda caroba. In the first experiment, alternating temperatures of 30/20 °C and 25/15 °C were applied under two light conditions (light and darkness). In the second, germination was assessed at constant temperatures ranging from 15 to 35 °C. Germination reached or exceeded 50% in both species under alternating temperatures and light conditions. In continuous darkness, J. caroba exhibited a higher germination speed and percentages, whereas C. pachystachya was unaffected by light conditions. The recommended alternating temperature for both species was 30/20 °C. The optimal constant temperatures were 25 °C for J. caroba and 30 °C for C. pachystachya. It is concluded that the nonparametric survival analysis technique effectively discriminates seed germination of the studied species.

Keywords

• Cecropia pachystachya
• censored data
• Jacaranda caroba
• photoperiod
• temperature