Effect of different environments in homemade germination chambers on the germination and growth of cacao (Theobroma Cacao L.) rootstock in the Lodana parish of Santa Ana canton

Abstract

The objective of this research was to evaluate the effect of thermotherapy on the germination and development of cacao rootstocks (Theobroma cacao L.). The experiment was conducted using a completely randomized design (CRD) with five treatments: (T1) Germination chamber with transparent plastic, (T2) Germination chamber with perforated transparent plastic, (T3) Germination chamber with transparent plastic and zaram shade, (T4) Germination chamber with dark plastic, and (T5) Traditional germination (control). The evaluated variables included: days to germination, seed germination rate (%), seed mortality rate (%), seedling height (cm), stem diameter (mm), vigor or slenderness index, root length (cm), fresh aerial biomass (g), fresh root biomass (g), dry aerial biomass (g), dry root biomass (g), and Dickson’s quality index (DQI). Results showed that T1 achieved the fastest emergence (6 days), followed by T2 and T3 (8 days), while T5 required 9 days. Germination percentage exceeded 97% in T1 and T3, with minimal mortality (≤ 2%), compared to 96.55% germination and 3.45% mortality in T5. Regarding growth, T1 and T3 produced taller seedlings (41.5 cm) with higher slenderness indices; however, no significant differences were observed in stem diameter among treatments. T2 promoted the greatest root length (38.2 cm), whereas T1 generated the highest total biomass and the highest DQI (~0.73), indicating balanced and vigorous growth. The use of transparent plastic chambers, particularly when combined with zaram shading or perforations for ventilation, accelerates germination and improves the quality of cacao seedlings.