Howick, South Africa
Howick, South Africa

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Kanzler A.,Sappi Forest Research | Nel A.,Sappi Forest Research | Ford C.,Sappi Forest Research
New Forests | Year: 2014

During the last 20 years a program to develop and commercialize the Pinus patula × Pinus tecunumanii hybrid, as a replacement for P. patula, has been successfully implemented. The first crosses were initiated during the early 1990s and lead to establishment of field trials across a wide variety of sites. This work gained further impetus when it became apparent that Fusarium circinatum, was causing poor post-planting survival of newly established stands of P. patula. P. tecunumanii, has been shown to be tolerant to this disease and thus a second, more comprehensive hybrid testing phase was implemented. Improvements in controlled pollination techniques and propagation methods, as well as access to genetically improved parent-stock and the use of molecular marker technology for fingerprinting was effectively utilized to greatly improve the process during this second phase. The use of artificial inoculation trials have demonstrated that the hybrid, in particular when using the low elevation (LE) provenances of P. tecunumanii, had substantially greater tolerance to F. circinatum than P. patula and survival figures from field trials support these results. Four-year volumes also indicate large growth improvements, although frost damage on certain sites presents a challenge for deployment on colder sites; and this is being tackled through breeding and accurate mapping of frost risk. Large-scale controlled pollinations and vegetative multiplication are now utilized commercially to produce the P. patula × P. tecunumanii (LE) hybrid as an alternative to P. patula. © 2014 Springer Science+Business Media Dordrecht.

Kanzler A.,Sappi Forest Research | Payn K.,Mondi South Africa | Nel A.,Sappi Forest Research
Southern Forests | Year: 2012

Two Pinus patula hybrids, P. greggii × P. patula and P. patula × P. tecunumanii, were planted across a number of sites in southern Africa. The growth and survival for each species/taxon was assessed at either 5 or 8 years of age at each site and compared to the respective parental species. Pinus greggii, as a pure species, has greater drought tolerance and is better adapted to harsher sites than P. patula. At 8 years the P. greggii × P. patula hybrid had similar survival and was more productive than P. patula at the two sites where it was tested. Furthermore, the performance of the hybrid was better than pure species on the site with average poorer growth suggesting that this hybrid could be planted on poorer, more marginal sites not well suited to P. patula. Pinus tecunumanii is a productive species with good tolerance to the pitch canker fungus (PCF). Previous work has shown that the P. patula × P. tecunumanii hybrid is more tolerant to PCF after field inoculations. The latter hybrid was assessed at 5 years on three sites and compared to both parent species. The hybrid had similar survival and was more productive than both parent species. Large variation in performance between individual P. patula × P. tecunumanii families suggests that comprehensive testing and selection should be conducted in tandem with any operational deployment of this hybrid. © 2012 Copyright NISC (Pty) Ltd.

Nel A.,Sappi Forest Research | Hodge G.R.,North Carolina State University | Mongwaketsi K.E.,Sappi Forest Research | Kanzler A.,Sappi Forest Research
Southern Forests | Year: 2014

The pine pitch canker fungus, Fusarium circinatum, has caused large-scale mortality of Pinus patula Schiede & Deppe ex Schltdl. & Cham. crops in South African nurseries. This disease is now managed with strict hygiene practices and mortality in commercial nurseries has been drastically reduced. During the last 10 years, however, the disease started to manifest in the field, impacting on post-planting survival. Tree breeders have identified selection and breeding of tolerant material as the likely long-term solution to this disease. This study demonstrates that, under greenhouse conditions with artificial inoculation of young seedlings, there is significant genetic variation in tolerance to F. circinatum among open-pollinated P. patula families. Tolerant families can be identified and can be utilised in breeding programmes and for seed production. The study provided strong evidence that these artificial inoculation experiments are highly repeatable within specific laboratories, with lower but still meaningful repeatability between different laboratories. © 2014 Copyright © NISC (Pty) Ltd.

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