Phenological Monitoring of Tomato (Solanum lycopersicum L.) in Response to Irradiated Carrageenan Biostimulant Under Water Deficit Conditions

Abstract

The phenology of tomato can be significantly affected by drought conditions, leading to several problems and challenges in their growth and development. Some key problems may include delayed emergence, poor fruit development, and yield reduction. Understanding these problems and their impact on tomato phenology under drought is crucial for developing strategies to enhance tomato production resilience and mitigate the negative effects of drought on crop yields. Moreover, this study will give insights into whether the use of carrageenan under water deficit conditions will contribute to improving tomato growth. There are several reports on the positive effect of carrageenan on the yield of various crops but very few or none at all on tomato, more so under drought or water deficit conditions. Thus, this study aimed to evaluate the growth and phenology of tomato using the BBCH scale with an emphasis on vegetative to reproductive growth shift. The experiment was conducted in Los Baños from July to October 2022. Results showed that the number of days to phasic transition and GDD did not affect plant phenology because the resulting values of ICB-sprayed plants are closely similar with that of control plants. For instance, transitions from seed germination to lateral shoot formation varied between 22 and 27 days (78 GDD) for treated plants, compared to 27 days (97.35 GDD) for the control. Similarly, from inflorescence emergence to flowering, treated plants ranged from 28 to 36 days (1030.20 GDD), while the control took 39 days (1127.95 GDD).