International provenance trials of Pinus patula were initiated in 1982 (see next page).
Results from the nursery phase in Nepal are summarized in the following.
Pinus patula is already a popular species in the middle hills (1 500–2 500 m) of Nepal and its potential for community forestry is considered high. The seed which until now has been most commonly used, has often been of seed orchard origin from Southern Africa (thus, of a reduced genetic base of unknown origin).
The trials in Nepal include 10 Mexican provenances of P. patula, 1 seed orchard source from New Zealand, and 1 seed orchard source from Southern Africa. One Mexican provenance of Pinus greggii is also included.
Seed was sown in small seed trays under sterile conditions in a high humidity wooden framed polyethene propagator in September 1984. The germination medium was heat sterilized sand. All seedlots started to germinate 10–12 days after sowing. Three seedlots (two Mexican, one from new Zealand) produced fewer transplants than expected, otherwise germination was excellent.
Some seed of the Southern African origin sown on a sand/soil open, unsterilized seedbed was subject to considerable loss due to damping off, probably caused by over-watering.
In late October, all seedlots were pricked out in lay-flat, transparent poly-pots filled with a sand/soil potting mixture. Survival of the seedlings was good and after the winter, seedling growth was normal. In April 1985, needle clorosis caused by a fungal root infection occurred on some individuals within most provenances. The disease was brought under control through root pruning, separation of seedlings and fungicidal treatment.
A prophylactic spray programme to avoid brown needle disease (Cercoseptoria pini-densiflorae) was started in December 1984.
The three seedlots which did not produce enough transplants were re-sown. Because of this delay, outplanting coincided with cold damp winter conditions and damping off occurred to a large extent. A third attempt of transplanting these seedlots at the end of January 1985, using two-month old germinants which had been kept in the propagators during winter, was successful.
Survival assessments based on all seedlings transplanted were made in April and May 1985. Height and root collar diameter were measured in June on a randomly selected sample of each provenance, excluding seedlings transplanted after October 1984 and those still showing symptoms of the root infection.
In general, quality of seedlings of all sources was very good.
P. greggii distinguised itself from all P. patula sources by showing best survival, being the tallest and having the smallest root collar diameter. It was also the only source completely unaffected by the root infection.
The New Zealand seed orchard source and the 3 best Mexican sources were comparable in terms of survival and growth. The New Zealand source did, however, show less variation
It was of interest to note that the seed orchard source from Southern Africa had comparatively poor hight growth and survival and also a relatively high variation in hight and root collar diameter.
The seedlings have now been planted out in replicated randomised block designs at two of the Forest Research Project trial sites in Central Nepal, Tistung (2 000 m) and Kharidunga (2 600 m), and it will be of interest to see whether any of the obvious differences in performance in the nursery are carried over after several years of development in plantation.
We remind you that the Pinus patula provenance trial which is coordinated by INIFA, Mexico, was announced in Forest Genetic Resources Information No. 11, page 54 (1982).
The address of INIFA (formerly INIF) has recently changed and is now:
Instituto Nacional de Investigaciones
Forestales y Agropecuarias, INIFA
Av. Insurgentes Sur, No. 694, 9° piso
Col. del Valle
03100 México, D.F.
MEXICO
