ABSTRACT
Effects of seed pre-soaking with aqueous extract of coconut shell biochar on biochemical profile of chiltepi­­n pepper (Capsicum annuum L. var. glabriusculum) under different light environments

Mari Carmen López-Pérez1, Ranjita Saikia2, Ernesto Fernández-Herrera3, Antonio Juárez-Maldonado4, 5, and Fabián Pérez-Labrada4*
 
Chiltepi­­n pepper (Capsicum annuum L. var. glabriusculum (Dunal) Heiser & Pickersgill) is a genetic resource with high economic potential; however, it shows high agronomic variability in response to the developmental environment. The aim of the present study was to investigate the effects of pre-soaking wild chiltepi­­n seeds in a coconut shell biochar aqueous extract (BC) on the phytochemical profile (leaf and fruit) and yield of chiltepi­n peppers under different light environments. The BC treatments studied were 0.00%, 0.05%, 0.25%, and 0.75% (BC0, BC05, BC25, and BC75, respectively) and the light environments studied were low (LLE, 180 ± 26 µmol m-2 s-1), medium (MLE, 437 ± 37 µmol m-2 s-1), and high (HLE, 959 ± 49 µmol m-2 s-1). In leaf tissue, BC25·LLE increased the total chlorophyll content by 7% and flavonoids by 13%. Vitamin C was higher in BC0·HLE (3.23 mg g-1 DW), while total phenols increased by 5.4% in BC25·HLE. RuBisCO presented the highest activity in BC05·MLE (126% higher than the control), whereas BC75·LLE increased phosphoenolpyruvate carboxylase (PEPC) activity by 92.9%. Fruit quality parameters such as phenols and flavonoids increased by 31.5% and 10.7% in BC25·HLE and BC05·LLE, respectively (p < 0.05). The BC05·MLE increased fruit production and yield by 118 % (p < 0.05) and 106%, respectively. Seeds pre-treated with 0.05% of BC and grown in an environment of 437 ± 37 µmol m-2 s-1 could be a reliable strategy to improve phytochemical profile and yield of chiltepin pepper.
Keywords: Capsaicin, carotenoids, radiation, RuBisCO, total phenols.
1Universidad Estatal de Sonora, Unidad Academica Navojoa, Navojoa 85875, Mexico.
2Asian Institute of Technology, Bio-Nano Material Science and Engineering, Khlong Nueng, Khlong Luang District, Pathum Thani 12120, Thailand.
3Universidad de Sonora, Departamento de Agricultura y Ganaderia, Hermosillo 83000, Mexico.
4Universidad Autonoma Agraria Antonio Narro, Departamento de Botanica, Saltillo 25315, Mexico.
5Universidad Autonoma Agraria Antonio Narro, Laboratorio Nacional Conahcyt de Ecofisiología Vegetal y Seguridad Alimentaria (LANCEVSA), Saltillo 25315, Mexico.
*Corresponding author (fabian.perezl@uaaan.edu.mx)