Intrapopulation recurrent selection in sweet sorghum for improving sugar yield

Abstract

Sweet sorghum [Sorghum bicolor (L.) Moench] accumulates fermentable sugars in the stalk making this crop an important bioenergy feedstock. The objectives of this study were to implement an intrapopulation recurrent selection program to increase the sugar yield in sweet sorghum [Sorghum bicolor (L.) Moench] and to estimate the genetic progress after a recurrent selection cycle for the main agro-industrial traits of interest. The base population for cycle 0 (C0) was developed from 15 fertility restorer lines using a genetic male-sterile source to promote recombination. A total of 196 half-sib progeny from C0 were evaluated in experiments with a 14 × 14 lattice design in the 2016–2017 season. The following traits were evaluated: days to flowering (DF), plant height (PH), fresh biomass yield (FBY), total soluble solids content (TSS) and tons of Brix per hectare (TBH). Data were analyzed using the mixed model approach. Genetic variation was observed among the C0 half-sib progeny for all of the agro-industrial traits studied. The 40 best progeny were selected based on the best linear unbiased predictions (BLUPs) for TBH, which were then recombined to form the base population for cycle 1 (C1). Subsequently, 40 half-sib progeny from each cycle (C0 and C1) were randomly selected and evaluated in experiments with a 9 × 9 lattice design to estimate the genetic progress for DF, PH, FBY, TSS and TBH traits. The genetic progress was significant, with increases of 3.73% for PH, 8.04% for FBY, and 8.65% for TBH, demonstrating the efficiency of the intrapopulation recurrent selection program used.