Traits and underlying genetics important for low‐input organic sorghum production

Abstract

Sorghum [Sorghum bicolor (L.) Moench] is a potential crop for organic production that could help meet the demand increase in organic food products and feed grains, but no efforts have been made to improve sorghum breeding tools, techniques, and methods for this cropping system. Based on revelations in other crops, focal traits and their prioritization to optimize sorghum for organic use likely differs from conventional sorghum breeding targets. This study evaluated yield performance, agronomic characteristics, and biotic stress resistance under certified organic practices in a range of grain sorghum genotypes that included 70 hybrids, 72 advanced breeding lines, and 43 diverse accessions, as well as 10 sweet sorghum cultivars and four commercial maize hybrids. Multiyear, multilocation trial data demonstrated that sorghum can be effectively produced using sustainable and organic inputs, but hybrid or cultivar selection is extremely important for success as entry means for grain yield ranged from 26 to 5,970 kg ha−1. Yields of top sorghum entries rivaled commercially available maize (Zea mays) hybrids. Overall, hybrids significantly outperformed inbred lines as heterosis proved beneficial for influential agronomic traits, although a Clemson F6 advanced breeding line, PV20_0426, ranked second in yield. Sugarcane aphid tolerance, increased canopy closure, and grain mold resistance were positively correlated with grain yield and should be considered target traits for breeding sorghum hybrids and cultivars for organic use. Depending on possible seed production constraints, developing pure line cultivars with the proper trait package may be effective to diminish this potential obstacle for the organic sorghum market.