Introgression of Resistance Genes from Feral Relatives Has No Impact on Yield Traits of ALS and Accase Inhibitor Herbicide Resistant Sorghum.

Though ranked second among the major feed crops, sorghum (Sorghum bicolor (L.) Moench) acreage showed a prickly decline over the past few decades. One of the factors responsible for continued reduction of acreage under sorghum is better weed control options that competing crops have offered. The discovery of the ALS and ACCase resistance traits in feral relatives of sorghum opened the path for breeding herbicide resistance into cultivated sorghum. However, because the resistance gene donors for both ALS and ACCase inhibitors represent wild relatives, there is a fair concern that some wild characteristics may drag in to cultivated types and undermine yield potential. The objective of this study was to compare the agronomic characteristics and productivity of large set of experimental hybrids with and without herbicide resistance traits. A total of 182 hybrids were grown in three sets at three locations in three replications during 2014 and 2015 crop seasons along with two commercial check hybrids. The experimental hybrids were synthesized by intercrossing seed and pollinator parents carrying ALS, ACCase herbicide resistance traits and those with our herbicide resistance genes. Of the total of 182 hybrids, 8 were ALS×ALS, 13 ACCase × ACCase, 48 ALS × ACCase, 7 ACCase × ALS, 12 Regular × Regular, 35 ALS × Regular, 25 ACCase × Regular, 13 Regular × ALS, and 21 Regular × ACCase. Date were collected on 11 different traits including yield and major yield components. Analysis of the data showed no significant difference among the hybrid categories though there was significant difference among the hybrids. The top performing hybrids were those from ALS × Regular, ACCase × Regular and ACCase × ACCase categories. The result indicates that deploying herbicide resistance traits does not seem to cause yield penalty.