Guayule (Parthenium argentatum Gray, Asteraceae) is a potential domestic source of natural rubber, but is presently not competitive economically with imported Hevea rubber. Guayule can become competitive by either increasing rubber yield or reducing the costs of cultural practices, or both. Pollarding, harvesting the branches by cutting leaving the root-crown to regrow new branches, can potentially increase both rubber yields and reduce the costs of stand establishment. The objective of this study was to determine the efficiency of mechanical-pollarding, and to determine if there were increased rubber yields one year after pollarding. A mechanical clipper was used to pollard shrub (accession N396), planted at the standard density of 36.650 plants ha. 17 and 29 months after stand establishment. Mechanical pollarding at 17 months left 19% of the branches unclipped on both a fresh and dry weight basis, representing 16% of the potential resin and rubber yield. After regrowth for one year (29 months), pollarded plants had increased fresh weight, dry weight and resin yield over non-pollarded plants of 25, 24 and 15%, respectively. However, rubber yield increased by only 3%, due mainly to the low rubber content in the regrowth. After a single pollarding (17 months) 98% of the plants survived and regenerated new growth. Plants pollarded two consecutive years (17 and 29 months) had only a 66% survival rate. The low rubber yield in the regrowth after one year, and the reduced survival rate of plants pollarded two consecutive years, suggests that a clipping interval of two years may be optimal for line N396.
- Guayule (Parthenium argentatum)
- Mechanical pollarding
- Rubber yield increase
ASJC Scopus subject areas
- Agronomy and Crop Science