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Abstract Detail

Botanical foundations for perennial agriculture: Evolution and ecology of perennial herbaceous plants

Ravetta, Damian [1], Vilela, Alejandra [1], Gonz├ílez Paleo, Luciana  [1], Van Tassel, David [2].

Domestication of Silphium integrifolium (Asteraceae): are we inadvertently moving the phenotype from a conservative to an acquisitive strategy?

Silphium integrifolium Michx. (silflower, wholeleaf rosinweed) is in the early stages of domestication as a perennial version of oilseed sunflower, its close relative. We evaluated changes brought about in the process of domestication as a case study to evaluate potential unwanted changes in structural and functional traits, when yield is used as the sole selection criteria. In order to check for progress in traits under direct selection (yield and its components), we established experiments in Kansas (U.S.) and Patagonia (Argentina), with wild populations and populations that underwent several cycles of selection for yield at The Land Institute. We evaluated seed-yield and yield components, and also checked for changes in early vigor, biomass allocation pattern, leaf morphology and anatomy, gas exchange, root acquisition capacity and defense compounds.
We found that selection for high yield increased desirable traits of a crop, such as reproductive output, seed size, capitulum size, and harvest index. Increases in plant biomass and seed production were sustained by changes in leaf anatomy (i.e. increase of xylem vessel’s diameter and increase of palisade parenchyma), changes in leaf morphology (thinner and bigger leaves) and changes in gas exchange (more CO2 uptake and transpiration), as well as reductions in carbohydrate reserves and leaf resin content.
Taken altogether these changes indicate a shift in the strategy of use of resources, from conservative, typical of perennial wild plants, to an acquisitive one, typical of crops (and in particular, annual crops). Similar changes have been found in other perennial oil-seed crops when yield components were the main breeding objective. Some of these changes may be inevitable and/or acceptable but others may represent a “path of least resistance” through a rugged fitness landscape leading to losses of ecologically desirable conservative traits that are inevitable only if breeders focus exclusively on high-level traits (yield) without monitoring and considering lower-level functional and anatomical changes.

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Related Links:
Silphium domestication at The Land Institute
Progress and Bottlenecks in the Early Domestication of the Perennial Oilseed Silphium integrifolium, a Sunflower Substitute

1 - National Scientific and Technical Research Council (CONICET), MEF, Fontana 140, Trelew, Chubut, Argentina
2 - The Land Institute, 2440 E Water Well Rd,, Salina, KS, 67401, United States

perennial grain candidates
functional traits
Leaf anatomy.

Presentation Type: Colloquium Presentations
Session: C02, Botanical foundations for perennial agriculture: Evolution and ecology of perennial herbaceous plants
Location: 102/Mayo Civic Center
Date: Monday, July 23rd, 2018
Time: 10:15 AM
Number: C02008
Abstract ID:576
Candidate for Awards:None

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