Performance of Pinus elliottii, Pinus caribaea, their F, F and backcross hybrids and Pinus taeda to 10 years in the Mesopotamia region, Argentina.

Performances of Pinus taxa were studied to 10 years of age in two trials in each of Misiones and Entre Ríos provinces across the Mesopotamia region of Argentina. Taxa comprised 22 populations from sources in Argentina, Australia, Brazil and Zimbabwe including Pinus elliottii var. elliottii (P ee), Pinus caribaea var. hondurensis (P ch), their four, inter-specific hybrids (F, F and backcrosses from F to P ch and to P ee-all as broadly based bulks); other P ee and Pinus taeda (P t) comprised narrower or unspecified bulks. Variable numbers of taxa were missing at each site. Mean survival across sites at age 10 years ranged 53.2-91.3% averaging 74.2%. Analysis of variance of plot means indicated population effect was statistically significant ( p < 0.05) for all or most growth and quality traits at all sites. However, significant differences from the nominated check seedlot at the Entre Ríos sites (P ee, Australia) were extremely rare, while quite common at the northern, Misiones sites (check seedlot a P t population). In the Misiones trials, F, F and both backcross hybrids showed better stem straightness than P ee and P t from Argentina, generally with statistically significant differences ( p < 0.05). P t showed lowest forking scores (desirable). Taxon × environment interaction was statistically significant ( p < 0.01) for growth traits only ( p > 0.05). However, this interaction contributed an average of only 34.1% of the taxon variance suggesting a lack of practical importance. Taxa most suitable for deployment in the Mesopotamia region, Argentina are suggested. [ABSTRACT FROM AUTHOR]