Gradient of Vernalization Requirement in Carrot Cultivars from Diverse Geographical Origins

WOHLFEILER, J.; ALESSANDRO, M. S.; CAVAGNARO, P. F.; GALMARINI, C. R.

CROP SCIENCE

CROP SCIENCE SOC AMER

Lugar: Baltimore; Año: 2021 p. 1 - 9

0011-183X

On the bases of the vernalization requirement for flowering, a genetically-conditioned trait, carrots are typically classified as annuals ?commonly wild carrots- and biennials ?most cultivated carrots. A previous study using F2 populations derived from crosses among carrots from different geographical origins revealed a model of two genes and three alleles controlling the vernalization requirement, with dominance of annuality for both genes, and suggested a certain amount of hours of cold exposure that each allele requires for the plant to become vernalized. The objective of the present work was to evaluate the vernalization requirement of the carrot cultivars used in our previous study in order to validate the dominance statement of the model.We induced vernalization in five cultivated carrots from diverse origins -including those used for this genetic model- during different periods of cold temperature exposure (20, 30, 40, 60 and 90 days) and different temperatures (~5 and ~15°C). Rates of flowering increased with the duration of cold exposure, and initiation of flowering took place earlier with longer cold inducement. A temperature of ~5°C was appropriate for vernalization but ~15°C was not. Biennials required longer periods of cold exposure than annuals to flower. However, variability among annuals and among biennials also occurred, suggesting the presence of a gradient for vernalization requirement in the carrot germplasm, which reinforces the genetic model proposed in our previous study. The plant materials used in this work cover the broadest range of vernalization requirements in carrot reported to date.