Stalk Lodging Phenotyping: An Improved Device.

Stalk lodging currently impedes efforts to develop superior grain varieties. In particular, efficiently identifying lodging resistant cultivars has been troublesome in the past due to lack of quantitative, reliable and unconfounded techniques for measuring stalk strength. This poster presents a novel, field deployable device that has been developed to accomplish this task. The device is able to measure both the applied breaking moment (torque) and the flexural rigidity of plants in the field. Flexural rigidity measurements can be obtained without damaging the plant and are highly correlated with stalk strength (R^2 > 0.5). Recent improvements to the device include a GPS sensor, an onboard screen and graphical user interface, as well as a temperature and humidity sensor. The ergonomics of the device has likewise been improved to increase plant throughput. In its current configuration the device can be operated by a single user and process approximately 200 maize plants an hour. Results from field tests conducted in 2016 and 2017 indicate that device measurements allow the differentiation of elite hybrids. Preliminary genetic analyses are planned for summer 2017 as well a direct comparison with rind penetration resistance ( a more commonly used method to phenotype stalk strength).