Initial Evaluation ofProsopis albaGriseb Clones Selected for Growth at Seawater Salinities

Abstract

In a previous article, growth and survival of Argentine and Peruvian Prosopis were measured in a greenhouse hydroponic system in which the salinities were increased from 10 to 45 dS m À1 . Twenty-one of the Prosopis alba seedlings that grew at the 45 dS m À1 salinity were propagated by rooting cuttings and a seed orchard= long-term evaluation trial established. To develop predictors and=or correlations between seedling and performance in mature field trials, this study characterized the seedlings for growth, leaf, and thorn morphology and ease in asexual propagation by rooting of cuttings. The percentage rooting of all clones varied from 40 to 100%, the roots per cutting from 0.60 to 67, and the length of the longest root from 1.63 to 6.70 cm. The parent trees were selected from P. alba specimens in a highly saline area of Argentina where P. ruscifolia Griseb (which has larger leaves and 15 cm long spines) was the dominant species. Some progeny were intermediate in spine and morphological characters between P. alba and P. ruscifolia and were locally known as vinalillo (P. vinalillo Stuck). The thorn length varied from 7.7 mm to 53.3 mm for the vinalillo ''species'' and from 0 thorns to 28 mm for P. alba. There was no correlation between leaf=thorn characters and salinity tolerance. The overwhelmingly greater abundance of spiny P. ruscifolia over P. alba may be due to livestock palatability rather than salinity tolerance. The increasing demand for the high-quality Prosopis lumber for furniture may make recuperation of moderately saline soils (<30 dS m À1 ) economically attractive.

Improving initial trials in tree breeding using kinship and breeding values estimated in the wild: the case of Prosopis alba in Argentina

“…Although genetic gains in clonal seed orchards are expected to occur faster than in seedling seed orchards (Felker and Guevara 2003), so far there is only one clonal orchard under evaluation with a narrow genetic basis. A cause for this is that high variability exists in P. alba clones for rooting ability (Felker and Guevara 2003;Felker et al 2008). Only 21 P. alba genotypes were asexually propagated by rooting cuttings using bottom heat, water soluble salts of plant hormones and Agrobacterium rhizogenes (Ewens et al 2012).…”

Five Year Field Evaluation of Prosopis alba Clones on pH 9–10 Soils in Argentina Selected for Growth in the Greenhouse at Seawater Salinities (45 dS m−1)

“…In spite of the fact that specimens were selected of P. alba mother trees in accordance with Burkart [17], great segregation in morphological characters was observed in the progeny. As described in other studies [18], some clones have finely divided leaflets typical of the P. alba mother tree while other clones have much larger and more widely spaced leaflets typical of P. vinallilo (little vinal). Some taxonomists have suggested P. vinallilo could be a hybrid between P. alba and P. ruscifolia [17].…”

“…As described earlier there was great variability among the clones for ability to produce roots from cuttings [18]. Fortunately, some of the highest biomass producing clones also had high rooting percentages.…”

“…In a previous paper [18], based on the growth at high salinity levels, it was suggested that none of these putative P. vinalillo progeny had significant growth advantages over P. alba and perhaps the greater ecological adaptability of the P. ruscifolia (parent in the P. vinallilo) over P. alba was due to the much greater palatability to goats of P. alba than P. ruscifolia.…”

Rooting of Prosopis alba mini-cuttings

“…Prosopis alba Grisebach, a species of the family Leguminosae, is of great importance in the arboreal composition of arid and semiarid regions (Felker et al 2008) and has great potential for the production of forest products (Ewens and Felker 2010). At present, this resource is obtained mainly from natural areas, via the intensive exploitation of native forests (Patch and Felker 1997).…”