Agronomic performance and the effect of genotype-by-environment interaction for Brassica carinata in the southeastern US

Abstract

Carinata (Brassica carinata A. Braun) is an emerging oilseed crop with potential as a dual use winter cover/cash crop in the southeastern US region. Although carinata is historically cultivated as a spring crop in northern latitudes, incorporating carinata into southeastern US cropping systems can provide winter/cover ecosystem services and a bio-feedstock for a high value, renewable aviation fuel without displacing feed and food crops. In this study, our major objective was to quantify the agronomic performance and stability of selected carinata genotypes across several locations in the southeastern US. Extensive field evaluations of twelve, elite carinata genotypes, arranged in a randomized complete block design with four replications, were conducted from 2016 to 2019 across Mississippi, Alabama, Georgia, Florida, South Carolina, and North Carolina. Data was collected on days to 50% bolting, days to 50% flowering, plant height, grain yield, and test weight. Results demonstrated the ability to produce viable grain yields across the region, but also highlighted the impact of freezing temperatures on winter production. In total 20% of all environments were lost to mortality due to freezing temperatures. Overall, genotype 15 produced the highest grain yield across individual environments, topping the trial in 74% of all environments. However, both crossover and non-crossover genotype × environment interactions were detected for agronomic traits, with problematic crossover interactions more prevalent for days to 50% bolting and days to 50% flowering. Our results also suggest the southeastern US be separated into three mega environments to include 1) northern Georgia, South Carolina, and North Carolina, 2) southern and central Georgia and Alabama, and 3) northern Florida. Future efforts to identify advanced breeding lines and/or commercial seed products with adaptation to the region should consider field testing in each of these mega environments.