Potential value of traits associated with perennial habit in the development of new oil-seed crops for arid lands. A comparison of Lesquerella fendleri and L. mendocina subjected to water stress

Lesquerella fendleri is an annual new oil-seed crop under the process of domestication.Lesquerella mendocina , on the other hand, is a perennial species native to the Monte region in Argentina and is not in the process of domestication at the present time. We analysed the impact of the perennial habit on several characteristics that might contribute to confer higher performances in sites with severe water stress limitations. Two experiments were carried out under controlled temperatures during two consecutive seasons. Biomass investment in roots and other vegetative organs, flowering rates between plants and within the plant, and gas exchange parameters were measured in L. fendleri and L. mendocina in both well-watered and water-stressed plants during flowering. Water stress increased the duration of the flowering phase by up to 15 days in L. fendleri and reduced the rate of stem production per plant by 20% at 110 days after sowing (DAS) in both species (p<0•01). Independently of the water treatment, only a fraction of the plants reached the reproductive stage in L. mendocina, while the number of reproductive stems per flowered plant was 50% lower than inL . fendleri (p<0•05). L. mendocina partitioned a higher proportion of biomass to roots and above-ground vegetative organs (p<0•05), and leaf water-use efficiency (WUE) was 35% higher (p< 0•05). The comparison of two related species of the same genus differing in life cycle clearly suggests that some traits of perennials have the potential to be introduced in breeding programmes for new oil-seed crops for arid lands.