Genetic mapping and localization of quantitative trait loci for chlorophyll content in Chinese cabbage (Brassica rapa ssp. pekinensis)

Chlorophyll a and chlorophyll b present in the chloroplasts of higher plants are the main pigments of leaf photosynthesis. The aim of this study was to localize the genetic factors affecting chlorophyll a and chlorophyll b content in the Chinese cabbage (Brassica rapa ssp. pekinensis) genome. To achieve this goal, we updated our previous genetic map, which was developed on the basis of an F2 mapping population derived from a cross between 2 diverse Chinese cabbage lines, ‘501’ and ‘601’ with additional unigene-derived microsatellite markers. Eleven new polymorphic markers along with 227 previously mapped marker loci were used to construct a new updated B. rapa map containing 238 marker loci and covering a total length of 926.7 cM, with an average distance of 3.9 cM between markers. Quantitative trait loci (QTL) mapping using the chlorophyll a and chlorophyll b phenotypic data from an F2:3 mapping population over 2 years identified 10 QTL in 8 genetic intervals in the Chinese cabbage accounting for 7–17% of the observed phenotypic variation.

► An updated genetic map was constructed containing 238 marker loci and covering a total length of 926.7 cM.
► Quantitative trait loci (QTL) mapping using the chlorophyll a and chlorophyll b phenotypic data over two years identified 10 QTL in 8 genetic intervals.
► Chlorophyll content is usually affected by various environmental factors.