Resumo

QUIROZ-VAZQUEZ, Rosa I.; LOPEZ-UPTON, Javier; CETINA-ALCALA, Víctor M.  e  ANGELES-PEREZ, Gregorio. Pinus pinceana Gordon reproductive capacity at the south limit of its natural distribution. Agrociencia [online]. 2017, vol.51, n.1, pp.91-104. ISSN 2521-9766.

Pinus pinceana Gordon is an endemic Mexican pine. Its distribution is fragmented, with larger areas in the northeast and scant in Hidalgo, where reproductive problems are expected. The aim of this study was to determine the seeds and cones production, from 2001 to 2003, at San Cristobal (SC) and El Arenalito (EA), El Cardonal municipality, Hidalgo, México, which are isolated populations in the southern part of the species natural distribution range. Five cones were collected from each of the 25 trees selected in each locality. Significant differences were found in five of twelve characteristics evaluated among populations with high variation between production dates. In 2001 cone production was higher, and seed production efficiency was of 54% and 55%. In 2002 it was of 41% and 32% and in 2003 of 38% and 18% in SC and EA, each. In 2001, 0.96 and 1.10 g seed per g cone were obtained at SC and EA, 0.85 and 0.70 in 2002, 0.76 and 0.45 in 2003 in those locations; this is a greater resources allocation to seeds in the highest cone production year. The number of empty seeds increased by 62% and 92% in SC and 125% and 131% in EA during 2002 and 2003. However, in years of high cones production years, a high production of filled seed cones is obtained, with similar weights between years, from 2.162 to 2.367 seed kg-1. There are no indications that these populations are under inbreeding depression effects, which is more related to natural variation between year’s low or high production, and the disparity between low and high cone production trees.

Palavras-chave : Efficiency; seed production; pine; marginal populations; cone production.

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