Evaluation of Pollen Contamination in an Advanced Scots Pine Seed Orchard

Abstract

The pollination pattern in a Scots pine (Pinus sylvestris L.) seed orchard consisting of 28 clones was studied using nine microsatellite (SSR) loci. The nine SSR loci produced unique multilocus genotypes for each of the orchard's 28 clones and allowed paternal assignment of the studied 305 seed using paternity exclusion probability of 99.9 %. Fifty two percent of the studied seeds were sired by outside the orchard pollen sources (i.e., pollen contamination) and as expected, low selfing (2.3 %) was detected. These results are valuable for the evaluation of the seed orchard function and the impact of contamination on the expected genetic gain.

Mating dynamics of Scots pine in isolation tents

“…The tent system evaluated here seems to be the most successful method of reducing pollen contamination developed to date. Although only small fraction of the control seed was found to be sired by background sources in each year (4.8-7.1 %), which is relatively much less than in majority of earlier studies (e.g., ElKassaby et al 1989;Harju and Nikkanen 1996;Nagasaka and Szmidt 1985;Torimaru et al 2009Torimaru et al , 2012Wang et al 1991;Yazdani and Lindgren 1991), our results suggest that under high pollen contamination rates typically reported in conifer seed orchards in Scandinavia, the significance of the tent isolation system on the economic revenue may be great.…”

“…50 % had been detected in it in pollination season 2006 (Torimaru et al 2009(Torimaru et al , 2012. This estimate may represent an extreme situation in the orchard or an up-biased estimation due to complicated banding patterns of some of the SSR loci that could have led to false paternity exclusion (see Funda et al 2015 for details).…”

“…Genotypes were determined at nine nuclear SSR loci, eight developed for loblolly pine (PtTX2146, PtTX3025, PtTX3107, PtTX3116, PtTX4001 (Auckland et al 2002), SsrPt_ctg1376, SsrPt_ctg4363 (Chagne et al 2004), and LOP1 (Liewlaksaneeyanawin et al 2004)) and one, SPAC12.5, developed for Scots pine (Soranzo et al 1998). PCR amplification was performed in simplex reactions as described in Torimaru et al (2009). DNA representing each of the 28 parents was isolated from frozen needles collected in the seed orchard in October 2007.…”

“…Offspring were sampled from known mothers and assigned to candidate fathers using a modified, null-assuming simple paternity exclusion method of Moriguchi et al (2004), described in Torimaru et al (2009) using strict exclusion criteria. The combined exclusion probability of the paternal parent over all loci was calculated following Jamieson (1965) and a correction factor was applied to account for the probability of false exclusion of the true father due to presence of a null allele, as proposed by Dakin and Avise (2004) …”

Variación espacial y temporal en la dispersión de polen en un huerto semillero y en rodales naturales cercanos de Pinus patula

“…Las diferencias en el inicio y duración del periodo de dispersión se debieron, al menos en parte, a la menor edad de los árboles en el huerto y a la variación genética en fenología reproductiva de los clones representados en este (Hernández-Zaragoza et al 2016). La dispersión de polen en huertos semilleros jóvenes puede ocurrir antes que en rodales naturales, porque en árboles jóvenes el pe-riodo de crecimiento del brote generalmente inicia antes y en los huertos el espaciamiento es mayor (Torimaru et al 2009). Además, la parte baja de la copa de los árboles jó-venes, donde se desarrollan los estróbilos masculinos, está cercana al suelo donde la temperatura es mayor, lo que puede acelerar el desarrollo de los estróbilos masculinos (Lindgren et al 1995), como se demostró en huertos de Pinus sylvestris (Harju y Nikkanen 1996).…”