Deciphering lodging resistance in oat and other cereal crops

Abstract

Lodging impedes the successful cultivation of oat and other cereal crops in the upper midwestern United States. Lodged cereals not only possess reduced grain yields, but also decreased grain quality. This dissertation first conceives of a camera system to capture plant movement in the wind in the field via a 360-degree field of view camera, followed by a video analysis pipeline to quantify the frequency and amplitude of cereal stem movement under varying wind conditions in the field. The natural oscillating frequencies and amplitudes of stems were dependent on wind speeds and at the cultivar, crop level. Nonetheless, the substantial environmental effects in the field that induce lodging make discovering specific morphologies that confer lodging resistance difficult. Next, in seeking to better identify promising morphological targets for breeding and selecting lodging resistance in cereal crops, a diverse panel of 38 cereal cultivars (oat, wheat, barley) were subjected to replicated testing in a wind tunnel. Wind tunnel testing revealed that a cereal ideotype consisting of low total biomass, high stem strength, and high stem elasticity should confer increased lodging resistance. A field study using the camera system to quantify aspects of plant movement and correlated these phenotypes with physical plant traits is presented next, which indicated that patterns of plant movement are spatially independent in a randomized complete block design of 16 cereal cultivars and that the relationships between plant height, heading date, and plant movement vary among the major cereal crops. Finally, a GWAS and QTL validation study is presented on lodging in oat, which revealed significant marker trait associations for plant height, heading date, and stem snapping, though only QTL for plant height and heading date were successfully validated in derived biparental populations.