Spontaneous Hybrids Within the Genus Abies – Growth and Development
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JOURNAL OF FOREST SCIENCE, 53, 2007 (5): 193–203 Spontaneous hybrids within the genus Abies – growth and development V. Janeček, J. Kobliha Faculty of Forestry and Environment, Czech University of Life Sciences Prague, Prague, Czech Republic ABSTRACT: Spontaneous hybrids within the genus Abies are considered to be better in growth and vitality in compari- son with Abies alba and parental species. Three plantations with this material were established in the Czech Republic. These plantations are regularly measured and examined. The results show a very high potential of this material for the purposes of Czech forestry practice. Keywords: genus Abies; hybridization The silver firAbies ( alba Mill.) is one of our most and reproduction of the most viable individuals. important tree species, not only from economic but As an additional (but not marginal!) solution the also from ecological aspects. High wood production introduction of other fir species and hybridization connected with positive (indifferent) incidence at a site should be used. predetermines silver fir for utilization in our forests. According to Greguss et al. (1994a) there are Its importance decreased in the 20th century mainly eight spontaneous hybrids within the genus Abies. because of its recession from Czech forests (and from Spontaneous hybrids grow better compared with forests of Central Europe generally). Its representation parental species. Present knowledge shows close in Czech forests decreased from 19.8% (natural tree affinity of some fir species and possibility of new species composition) to 0.9%. Silver fir representa- hybrid origination. tion in the recommended tree specie composition of Of course, scientists investigated very good growth Czech forests should be 4.4% (Anonymous 2004). and vitality. In 1868 the first artificial hybrid was ob- The viability of surviving local fir populations has also tained by Hugo de Vilmorin. It was Abies cephalonica decreased. According to Forests of the Czech Republic × Abies pinsapo, named later as Abies vilmorini. This (the company managing 60% of Czech forest land) hybrid had a plenty of full and viable seeds (Paule there are 28 local populations on the edge of extinc- 1992). It means that hybridization, especially inter- tion. The number of silver fir trees in these populations specific one, is a verified way of increasing fir general has to be increased very soon (Indra 2002). resistance and viability (Greguss et al. 1994a). The Its occurrence in our forests extremely decreased hybrids within the genus Abies both from spontane- probably due to the following factors widely discussed ous and artificial hybridization distinguish them- in literature: the change in ecological conditions, dif- selves by heterosis from parental species not only in ferent methods of management (preferring Norway growth but also in increased viability. We can expect spruce), lower genetic variability, high game stocks, higher tolerance in fir hybrids in this aspect not only air pollution pressure, parasite pressure, grazing re- to various obligatory stress factors but also to possi- striction or phylogenetic age of this species. ble consequences of changes in ecological conditions There are three ways of solving the problem of caused by the climate warming. silver fir decline. The first and the most important Rohmeder and Schönbach (1959) reported that is in situ conservation connected with selection interspecific hybrids of Abies alba, Abies veitchii, J. FOR. SCI., 53, 2007 (5): 193–203 193 Abies concolor, Abies procera and Abies nordmanni- MATERIAL AND METHODS ana grew faster than intraspecific hybrids.Mergen and Gregoire (1988) measured the height and di- According to findings mentioned earlier compara- ameter of 17-years-old hybrids that originated from tive plantations with spontaneous hybrids within the crossing realized in 1960 and 1962 in Connecticut, genus Abies were established in the Czech Republic. USA. Abies cephalonica, Abies firma, Abies ho- There are three plantations there – one in Kostelec molepis, Abies koreana, Abies lasiocarpa, Abies nad Černými lesy (Central Bohemia) and two in mariesii, Abies procera, Abies sachalinensis and Forests of the Town of Prostějov (Central Moravia). Abies recurvata were used in this experiment. The They were established to evaluate possibilities of hy- results showed better growth and vitality compared brid utilization in Czech forestry practice. Plantation to the control material (Abies balsamea). French characteristics are shown in Table 1. researchers (Arbez et al. 1990) studied Mediterra- The material on these plots originated from Kysi- nean fir species and their hybridization. They recom- hýbel’ Arboretum in Slovakia. Seeds of spontaneous mended the utilization of fir progenies from selfing hybrids within the genus Abies were obtained there because of their inbreeding tolerance. in 1990. Seeds were collected from 21 trees. Trees Kantor and Chira (1971) investigated fir hy- number 1–3 and 6–21 incline in phenotype to Abies bridization in former Czechoslovakia using Abies cephalonica, tree number 4 to Abies cilicica and alba, Abies cephalonica, Abies nordmanniana, Abies number 5 to Abies numidica. Table 2 shows the basic pinsapo, Abies cilicica, Abies concolor, Abies grandis mother tree characteristics. These seeds were sown at for interspecific and intraspecific hybridization. Truba Tree Breeding Station of the Forestry Research Greguss (1986, 1988a,b, 1992) and Kormuťák Institute in Kostelec nad Černými lesy in spring 1991. (1985, 1986, 1992) studied fir hybridization in Slova- Five (six) years old plants were used for the establish- kia. Greguss (1986) reported slower growth of silver ment of comparative plantations. Abies alba from fir in comparison with fir hybrids and increasing differ- open pollination was used as a control material. entiation between hybrid progenies and progenies of The plantation in Kostelec nad Černými lesy was individual species from open pollination. Kormuťák established in 1996. There are hybrids planted to- (1986) presented similar results. He recommended gether with Abies nordmanniana, Abies balsamea, primarily these combinations for planting in our Abies grandis, Abies procera, Abies concolor and conditions: Abies alba × Abies cephalonica, Abies ce- hybrid progeny of Abies koreana × (Abies cilicica phalonica × Abies numidica, Abies nordmanniana × × Abies cephalonica). All progenies are planted in Abies alba, Abies pinsapo × Abies cephalonica, Abies blocks (replications) of 5 × 5 seedlings at a spacing pinsapo × Abies alba, Abies numidica × Abies nord- of 1.2 × 1.2 m. The uneven number of seedlings is manniana, Abies numidica × Abies cephalonica and a result of damage caused by extreme humidity in Abies concolor × Abies grandis. That means mainly the 1996 which caused 100% mortality on a part of the use of Abies alba and Mediterranean tree species. The plantation. same species already played the most important role The first plantation in Prostějov was established in experiments of Kantor and Chira (1971) and also in 1996. All progenies are planted in blocks of Greguss (1988a,b, 1992, etc.). 5 × 5 seedlings at a spacing of 1.5 × 1.5 m. Table 1. Basic characteristics of the plots Plot Kostelec Prostějov 1996 Prostějov 1997 Forest region 10 30 30 Forest altitudinal zone 2 3 4 Altitude (m a.s.l.) 380 480 530 Slope (%) 0 0 5 Bedrock sandstone sandstone sandstone Forest type 2K, 2I 3S 4K Annual rainfall (mm) 682 802 802 Vegetation period rainfall (mm) 352 414 414 Average temperature (°C) 7.8 8.3 8.3 Vegetation period average temperature (°C) 16.2 17.8 17.8 194 J. FOR. SCI., 53, 2007 (5): 193–203 Table 2. Table of mother trees in Kysihýbel’ Arboretum, their progenies are planted on plots in Kostelec nad Černými lesy and Prostějov (Greguss, Longauer 1993) Number in Number d Height Number of the plot 1.3 comparative of the tree (cm) (m) plantations Abies cephalonica (Loud.) × ? Planted: 1910 1–12 1 57 26.5 1 2 49 26 2 6 50 26.5 3 Abies cilicica (Carr.) × ? Planted: 1910/14 1–14 3 43 26 4 Abies numidica × ? Planted: 1949 1–64 13 35 21 5 Abies cephalonica (Loud.) × ? Planted: 1938 4–6 6 28 22 6 8 27 20 7 17 32 22.5 8 18 27 21 9 40 30 24 10 The first and the second column are used for determination of the tree in Kysihýbel’ Arboretum. The third and the fourth column show basic characteristics of the tree and the fifth column indicates the number of progeny in plantations The second plantation in Prostějov was established (below 20%) was found in progenies 5, 6, 16, 18 and a year later, in 1997. The conditions of this planta- 20. The mortality of progenies 1, 3, 15, 21 was high tion are extremely dry. All progenies are planted in (above 40%). Very low mortality was found in Abies blocks of 5 × 5 seedlings at a spacing of 1.5 × 1.5 m. balsamea – 6% and Abies procera – 4%. The hybrid Spontaneous hybrids together with Abies grandis Abies koreana × (Abies cilicica × Abies cephalonica) were planted there. The control material of Abies also had low mortality of 14% while the mortality of alba was planted a year later. Abies grandis (40%) was very high. Measurements of this material were realized in In the plantation Prostějov 1996 the mortality 2002 and 2004 (and/or 2005) always after the vegeta- increased up to 25% in 2005 in comparison with the tion period. Mortality was determined, and height year 2002, so there is a 1% change. High mortality was measured to the nearest 1 cm. The results were over 30% was found in progenies 4 (34%), 9 (33%) and statistically processed – UNISTAT programme ver- 16 (31%). Progenies 18 (10%), 2 (15%) and progeny sion 5.1. was used. The basic statistical characteris- mixture marked by × (18%) had very low mortality. tics were obtained. Analysis of variance was used for Average mortality in the plantation Prostějov 1997 data testing. In the case of the absence of homogene- was 24% in 2005. It ranged from 1% (progeny 7) to ity of variance, non-parametrical Kruskal-Wallis test 60% (progeny 3).