Seed-yield and yield components response to source–sink ratio in annual and perennial species of Lesquerella (Brassicaceae)

Author: W.J. Masnattaa, D.A. Ravettaa,
Date: May 2011
Abstract: Although the annual Lesquerella fendleri is the prime candidate for the development of a lesquerolic rich oil-seed crop, within this genus there are other species available to breeders, some of which are perennials. However, the feasibility of a perennial crop of Lesquerella is not clear because increases in seed-yield tend to reduce perennially. The objective of this work was to determine the effect of the source–sink ratio on seed yield and yield components in annual and perennial species of Lesquerella. We predicted that (i) due to differences in allocation patterns of annual and perennial species, seed-yield and yield components in perennials would be less affected by the source–sink ratio (higher stability) than in annuals and (ii) since seed-weight has been found to be the most stable yield component in other crops and their wild relatives, most of the variation in seed-yield as a consequence of source–sink ratios would be determined by changes in the number fruits per plant and the number of seeds per fruit. A field experiment was carried out in Chubut, Patagonia Argentina in a complete randomized design with four treatments to examine source–sink relationships in four species of Lesquerella, two annuals (L. angustifolia, L. gracilis) and two perennials (L. pinetorum, L. mendocina). We used either shading (reduction of source) or removal of flowerbuds (reduction of sink) to develop a range of source–sink relationships. All four species showed a similar yield response to source–sink variations. Seed-yield was lower in shaded plants, although the timing of shading influenced this response. Flower-bud removal resulted in a significant increase in seed-yield. Seed-yield differences among source–sink treatments were best explained by changes in the number of fruits per plant than by the number of seeds per fruit. Source–sink manipulations had no affect on seed weight. Flower-bud removal significantly increased the number of fruits per plant in all species except for L. mendocina. The number of seeds per fruits increased only in L. pinetorum. Our results show that carbon stored during pre-anthesis plays a key role in reproduction both in annual and perennial Lesquerella. The increase in the seed-yield components found with bud removal could potentially reduce longevity in perennial species. The results also show that the number of fruits per plant is a good proxy for seed-yield within a species.

Relationships between reproductive output, morpho-physiological traits and life span in Lesquerella (Brassicaceae)

This research evaluates the reproductive output and ecophysiological traits in annual and perennial Lesquerella (commonly known as Bladderpod). The plants showed a gradation in traits that provide drought-tolerance or high productivity. Perennial species showed drought tolerance traits whereas other species showed intermediate values of traits, related with productivity and drought tolerance.

Author: Luciana González-Paleo, Damián Ravetta
 March 2011
Affiliation: Industrial Crops and Products
Abstract: The development of perennial industrial crops could contribute to increase agriculture sustainability and yield stability in arid environments. Since perennial plants allocate resources preferentially to perpetuation and to structural and functional characters that provide drought tolerance, they tend to have lower reproductive output (yield) than their congeneric annuals. Four species of Lesquerella native to arid regions were evaluated to understand the relationships between reproduction, drought tolerance, and their association with the plant’s life span. We assessed the following set of characters (defined as plant strategies): phenology, gas exchange, specific leaf area, leaf area ratio, total biomass and biomass allocation. Annual (Lesquerella gracilis and Lesquerella angustifolia) and perennial (Lesquerella mendocina and Lesquerella pinetorum) species were compared under water limiting conditions. Within this set of species differences in structural and functional characters were observed… Read full research article here.

Lesquerella : New crop development and commercialization in the U.S.

Author: D.A. Dierig et al
 January 2011
Affiliation: Industrial Crops and Products
Abstract: While Lesquerella fendleri Gray (Wats.) is not yet a commercial crop, its history serves as a model for new crop development. The most important characteristic is the absence of any significant biological barriers to commercialization. Other potential crops may have valuable, high-demand products but possess traits difficult to overcome such as seed shattering or poor yield capacity. Lesquerella has a distinctive plant architecture that is conducive to seed productivity under a variety of conditions, and the trait could be further exploited. The plant also has high amounts of within-species and interspecific genetic diversity allowing breeding improvements in traits including oil quantity and quality. The unique seed oil is predominately composed of a hydroxy fatty acid, lesquerolic acid (C20:1OH), that is similar to ricinoleic acid (C18:1OH) found in castor oil. Improvements in agronomics will help increase seed yields, water use efficiency, while reducing crop production costs. New tools offered by remote sensing will help plant breeders and growers assess crop development. Defining herbicides and obtaining registrations for use in lesquerella appears to be the biggest obstacle for commercialization of this crop. The improvements in agronomics, breeding, genetics, and the expansion of new markets started in the 1980’s, and has made lesquerella a viable potential crop that could utilize thousands of hectares in arid climates of the world provided research continues.

Read full article here.