Production of thornless Cnidoscolus phyllacanthus Pax. et K. Hoffm. progenies from open pollinated native trees

Abstract

Cnidoscolus phyllacanthus (faveleira), a caatinga xerophyte Euphorbiaceae tree, produces proteinrich
forage consumed by ruminants. It should be used carefully due to urticaceous thorns in leaves, fine branches and fruits, and antinutritional substances present in fresh material. The narrow gene pool of the few thornless mutants should be widened by additional thornless individuals grown from open-pollinated seeds. This study checked the potential of six thorny and three thornless open-pollinated native trees in a caatinga site to produce thornless progenies, and estimated the proportion of their thornless progenies. The trial took place at the seed laboratory and seedling nursery facilities of UFCG/UAEF, Patos-PB, Brazil, from March 2002 to November 2003, in a completely random design with nine treatments (trees) and number of replications depending on seed and seedling quantity. Proportions of germinated seeds and thornless progenies were compared by the Student´s "t" test. Seven of the monitored trees produced thornless progenies (5.8% to 20.6%) consistently in two years.
Three thorny and two thornless trees generated 15.1% to 20.6% of thornless progenies. Thornless progenies
should be grown isolated to produce genetically improved seeds for the thornelss trait with a wide gene pool basis for distribution to local farmers and use to improve other traits such as forage and seed oil production. Further studies should investigate the genetic basis involved in the exhibition of this trait and if other trees in other C. phyllacanthus populations can produce thornless progenies as well.

doi: 10.4336/2010.pfb.30.62.147