Light-mediated self-organization of sunflower stands increases oil yield in the field

Abstract

Here, we show a unique crop response to intraspecific interference, whereby neighboring sunflower plants in a row avoid each other by growing toward a more favorable light environment and collectively increase production per unit land area. In high-density stands, a given plant inclined toward one side of the interrow space, and the immediate neighbors inclined in the opposite direction. This process started early as an incipient inclination of pioneer plants, and the arrangement propagated gradually as a “wave” of alternate inclination that persisted until maturity. Measurements and experimental manipulation of light spectral composition indicate that these responses are mediated by changes in the red/far-red ratio of the light, which is perceived by phytochrome. Cellular automata simulations reproduced the patterns of stem inclination in field experiments, supporting the proposition of self-organization of stand structure. Under high crop population densities (10 and 14 plants per m2), as yet unachievable in commercial farms with current hybrids due to lodging and diseases, self-organized crops yielded between 19 and 47% more oil than crops forced to remain erect.

The genetics underlying natural variation of plant–plant interactions, a beloved but forgotten member of the family of biotic interactions

“…Mathematical leaf models showed in silico that perception and response to light signals in distinct leaf areas should increase growth in densely populated environments (Pantazopoulou et al, 2017). Low R:FR ratio in densely planted sunflower fields leads to alternate stem inclinations, which is required for increased oil production per land area, thereby illustrating the adaptive value of neighbor detection in cropping systems (L opez Pereira et al, 2017). Low R:FR ratio also modulates the expression of jasmonic acid (JA)-mediated immunity genes in a species-specific manner (Gommers et al, 2017).…”

Rewiring of auxin signaling under persistent shade

“…These cues are sensed via a reduction in the activity of photosensory receptors, mainly phytochrome B (phyB) and cryptochrome 1 (cry1), consequently initiating shade-avoidance responses such as the promotion of stem and petiole elongation (1)(2)(3). Light-driven changes in canopy architecture can significantly impact yield of agricultural crops (4).…”

Shade-avoidance responses become more aggressive in warm environments

“…water availability) are not considered by the current growth model and could distort this trend. Bearing in mind this limitation and taking into account that shade-avoidance responses have both negative (Robson, McCormac, Irvine & Smith 1996) and positive effects (López Pereira, Sadras, Batista, Casal & Hall 2017) on crop productivity, the sensitivity to neighbour cues might need to be modified to optimise crop plant architecture in the context of global climate change.…”