Half-sib families from high yielding plants, grown in patagonia. yield, structure and function

RAVETTA, D.A.; GONZÁLEZ-PALEO, L.; VILELA, A; VAN TASSEL, DAVID L.

Salina, Kansas

Workshop; Fourth International Silphium meeting 2019; 2019

The Land Insitute

HALF-SIB FAMILIES FROM HIGH YIELDING PLANTS, GROWN IN PATAGONIA. YIELD, STRUCTURE AND FUNCTIONDamian Ravetta, Luciana Gonzalez-Paleo, Alejandra Vilela, David Van Tassel. Museo Egidio Feruglio- CONICET, Argentina and TLIThe objectives of this experiment are several fold: 1.Select for high yielding lines in an environment with low pest and disease pressure; 2.Estimate heritability of leaf structure, anatomy and function; 3. Continue divergence selection for resource use strategy: characterize and select lines and individual plants with high CO2 assimilation (A) and low A strategies.Materials and Methods. A set of 100+ 5th generation plants was followed for 3 years in Salina, Kansas. On these plants we evaluated yield and yield components, nitrogen usage, carbohydrate reserves, and leaf structure and function (manuscript in preparation). Half-sib families from these 100 plants (20 plants per line) are been grown now in Patagonia. The report in this abstract is from these half ?sib families. Seedlings were transplanted in April 2018 on flat beds, and flood irrigated during establishment. Lines are 1.3 m apart to allow for mechanical weed control. Plants are spaced at 50 cm.Measurements: 1. Phenology: precociousness (bolted and flowered the first year?) and earliness (earlier or later in the flowering season); 2. Growth: total biomass and number of stalks; 3. Seed-yield: number of capitula, seeds per capitulum, seed-weight; 4. Gas exchange: CO2 uptake and transpiration; 5. Leaf morphology: Leaf area, weight, specific leaf area and thickness.In another experiment we selected 3 from the 100 half sib lines: a) all plants in the line flowered, b) no plant in the line flowered, and c) 50% of the plants flowered. These plants were uprooted and biomass was partitioned and carbohydrate reserves determined. The goal was to determine signals that trigger precociousness. Preliminary results: There were significant differences in precociousness between lines: most lines flowered this first year although there were lines with 100% of the plants flowered, some lines that did not flower, and some intermediate lines with various proportions of flowering/non-flowering plants. Also, significant differences between lines were found in all morphological and physiological variables. Gas exchange was consistently different bewteen lines, when meassured at preflowering and and seed-filling, with lines of high A (Net CO2 uptake) and low A.Biomass and seed yield also greatly differed between lines that flowered this first year. The highest yield was 114g of seed/plant in two lines . Average yield for all lines that flowered was: 40g/plantWe have selected the highest yielding lines and also some individual plants from other lines to continue the selection process. Another set of plants has been selected just considering leaf structure and function in two groups: high A (acquisitive plants) and low A (conservative plants).