Morphological and molecular description of three commercial Capsicum varieties: a look at the correlation of traits and genetic distancing

Abstract

Capsicum L. is a genus of vegetables with a high global demand due to the pungency of its fruits. The species C. annuum L., C. frutescens L. and C. chinense Jacq. are the most cultivated and are closely related, belonging a group known as the annuum complex. Within these species, there are varieties with great morphological diversity that are widely exploited commercially. In this study, morphological measurements were performed on commercial chili pepper varieties, including Tabasco (C. frutescens), Cayenne (C. annuum) and Habanero (C. chinense), which are widely cultivated in the southwestern Colombian region, to generate a detailed phenotypic description and determine the correlation between traits. Additionally, microsatellite and SNP molecular markers were implemented to evaluate the genetic distances between them. The probability of forming hybrids between these varieties was also evaluated. Descriptive statistical parameters were estimated for the traits evaluated in forty plants of each commercial variety, and positive morphological correlations were found between the number of seeds, fruit mass and fruit length, as well as the independence or low correlation of this trait group versus the fruit diameter, day of first flower, number of fruits and productivity. The fruit capsaicin contents were estimated, with Habanero being the most pungent with 54.37 ± 5.83 mg/g. Molecular characterization using microsatellite markers and SNPs demonstrated the absence of heterozygous individuals and wide genetic distances between the commercial varieties evaluated; this outcome supported the impossibility of forming hybrids. The high genetic similarity among individuals within varieties could be useful to explore phenotypic plasticity in different environments. The methodology used here proved to be robust in testing trait correlation and cultivar genetic distancing, showing a look at the morphological and molecular relationships inside the genus which can be improved with the inclusion of more varieties. This information is especially useful for growers and breeders who wish to use and evaluate these plant materials.