Evaluation of leaf carbon isotopes and functional traits in avocado reveals water-use efficient cultivars

Abstract

Plant water-use efficiency (WUE) describes the ratio of carbon gain to water loss during photosynthesis. It has been shown that WUE varies among crop genotypes, and crops with high WUE can increase agricultural production in the face of finite water supply. We used measures of leaf carbon isotopic composition to compare WUE among 24 cultivars of Persea americana Mill (avocado) to determine genotypic variability in WUE, identify potentially efficient cultivars, and to better understand how breeding for yield and fruit quality has affected WUE. To validate carbon isotope measurements, we also measured leaf photosynthetic gas exchange of water and carbon, and leaf and stem functional traits of cultivars with the highest and lowest carbon isotope composition to quantify actual WUE ranges during photosynthesis. Our results indicate large variation in WUE among cultivars and coordination among functional traits that structure trade-offs in water loss and carbon gain. Identifying cultivars of subtropical tree crops that are efficient in terms of water use is critical for maintaining a high level of food production under limited water supply. Plant functional traits, including carbon isotopes, appear to be an effective tool for identifying species or genotypes with particular carbon and water economies in managed ecosystems.

Variability in physiological responses of Venezuelan cacao to drought

“…A poor relationship between δ 13 C and instantaneous WUE and between δ 13 C and A/g s was obtained when data of all clones were pooled. A positive linear relationship between δ 13 C and instantaneous WUE has been observed in fast-growing crop species such as wheat (Farquhar and Richards, 1984), barley (Hubick and Farquhar, 1989), cotton (Hubick and Gibson, 1993), beans (Monti et al, 2006), and sugar beet (Rajabi et al, 2008), and between A/g s and instantaneous WUE in avocado (Acosta-Rangel et al, 2018). In contrast, values of WUE in grapevines at different time scales did not follow the trend in values of δ 13 C (Medrano et al, 2015) and, in Poa pratensis (Ebdon et al, 1998), environmental factors such as air temperature and Δ W caused a negative relationship between δ 13 C and WUE.…”

“…Long-term WUE is an important trait associated with yield and adaptation to water deficit (Monti et al, 2006;Rajabi et al, 2008). The ability to recognize genotypes that combine high yield with high WUE is essential when breeding crops for drought-prone areas (Acosta-Rangel et al, 2018;Dias et al, 2007;dos Santos et al, 2016). Although the importance of screening large numbers of crops under similar agricultural management has been recognized, many breeding programs fail due to inappropriate clone choice for a certain region as a consequence of inadequate knowledge of the potential of clones and their growth and productivity under different site conditions (Rajabi et al, 2008).…”

Carbon Isotope Discrimination (δ13 C) of Grape Musts Is a Reliable Tool for Zoning and the Physiological Ground-Truthing of Sensor Maps in Precision Viticulture

“…To our knowledge, our study is the first work where a relationship of δ 13 C of grape musts with A N and g s is presented, and between δ 13 C and WUEi with such a large and diverse dataset (Figure 4). Our results are corroborated by those obtained in different crops such as avocado (Persea Americana Mill., Acosta-Rangel et al, 2018), peach (Prunus persica, L., Pascual et al, 2016), and rice (Oryza sativa, L., Tao et al, 2015).…”

Fire-fallow agriculture as a sustainable cropping system for maintaining organic carbon in Maré Loyalty Island (New Caledonia, southwest Pacific)

“…The impact of this straw mulch on the soil is notably highlighted by the 13 C values of SOC. 13 C values of avocado leaves in different cultivars range from −32.62 to −27.17‰, i.e., in the same range as other C3 vegetation (Acosta-Rangel et al 2018). Thus, while the soils of other avocado orchards (Tawaïnèdre, Taodé) and forests have 13 C signatures relating to their dominant C3 vegetation, the SOC of the Atha orchard is enriched in 13 C because of C4 plant biomass inputs from straw mulch (Balesdent et al 1987).…”