Phenotypic Recurrent Selection and Heritability Estimates for Total Dissolved Solids and Sugar Type in Carrot

Abstract

Abstract Five cycles of phenotypic recurrent selection for total dissolved solids and sugar type (reducing vs. nonreducing) were performed on four carrot (Daucus carota L.) populations of common background. The populations contained high or low percentage of total dissolved solids (HTDS and LTDS, respectively) with high or low levels of reducing sugar (HRS and LRS, respectively). Effective selection for total dissolved solids (TDS) and sugar type was indicated by significant gains over five cycles of selection. TDS decreased in LTDS/HRS and LTDS/LRS populations by 21.9% and 15.9%, respectively. Corresponding increases of 22.4% and 28.2% were observed in HTDS/HRS and HTDS/LRS populations. Mean reducing sugar levels in HRS roots after five cycles of selection were limited to 2.0% of root fresh weight; sucrose was the primary storage carbohydrate. Reducing sugars were not detected in LRS roots. Mean total sugar levels in the HTDS and LTDS populations were 7.1% and 3.1% of root fresh weight, respectively. Realized heritability estimates ranged from 0.40 to 0.45 for the four populations. The onset of flowering was markedly delayed in plants of the two HTDS populations after five cycles of selection.