No abstract

No abstract

tion on the genetic structure of Turkish red pine (Pinus brutia Ten.) populations determined by RAPD markers. Silva Fennica 41(2): 211-220. To determine the possible impact of over-exploitation on the genetic structure of Turkish red pine (Pinus brutia Ten.) populations, three natural and three over-exploited (human degraded) populations of the species in the Mediterranean region of Turkey were investigated with Randomly Amplified Polymorphic DNA (RAPD). With the 80 RAPD primers tested, 12 of them yielded 137 polymorphic RAPD fragments. Four of the studied populations maintained unique fragments. The mean proportion of polymorphic fragments for all populations ranged from 89.8 to 98.9% and there were no significant differences between natural (94.8%) vs. over-exploited populations (92.7%). The estimated heterozygosity values suggested that Turkish red pine maintains high levels of genetic diversity (range 0.24-0.28) though studied populations and grouped ones as natural (H e = 0.28) vs. over-exploited (0.27) did not differ significantly. The mean F ST value indicated that the large portion of the total genetic diversity was within populations (93%), but this value was lower in the natural populations (92%) than in the over-exploited ones (94%). In over-exploited populations, excess of homozygosity was observed (about 6% higher) as compared to natural populations, indicating impacts of inbreeding in P. brutia.

Developing new sugarbeet varieties with conventional plant breeding methods is slow and labor intensive. Integrating tissue culture methods with conventional methods could facilitate this process for some traits. This study investigated the effect of culture media sucrose concentrations on phenolic concentration and tissue necrosis of explant, and shoot regeneration frequency. Petiole and leaf disc explants of three sugarbeet (Beta vulgaris L.) breeding lines were excised from sterile seedlings and cultured on media containing different sucrose concentrations. The lowest phenolic concentration and tissue necrosis were recorded from both explants of all lines at 0% sucrose concentration. However, at this concentration, explant growth slowed and no shoots were regenerated. The best shoot regeneration success was obtained from media supplemented with 1% sucrose, 1 mg l-1 6-benzylaminopurine (BAP) and 0.2 mg l-1 naphthaleneacetic acid (NAA). At higher sucrose concentrations in the culture media, phenolic concentration and tissue necrosis increased and sharp decreases were observed in shoot regeneration of the three sugarbeet lines.

No abstract

Wind-pollinated seeds from 40 trees (half-sib families) were collected from each of six Turkish red pine (Pinus brutia Ten.) populations in southern Turkey. Two-year old seedlings were evaluated for growth, phenology and cold resistance in a common garden experiment established in Ankara, located outside the species’ natural range. Each family was represented with a six-tree row plot within each of the three replications. The below freezing temperatures (-15.2°C) observed in January and February of 2000 were sufficient to observe visually- assessable-cold damage to the seedlings. The populations significantly differed in all traits under investigation except for second flushing in 1999. Populations originating from more inland and higher elevation areas were more resistant to cold than coastal low elevation populations. Families within populations were significantly different as regards all traits except HT00. Family heritability for bud burst was 0.40, and ranged from 0.12 to 0.37 for height, and from 0.20 to 0.23 for bud set. Final height of cold damage prone seedlings was shorter than cold tolerant seedlings. Families with early bud-set, later bud-burst and shorter second flush shoots suffered less from cold damage. Considering the expected climate change in the eastern Mediterranean, there is a potential for using this species outside its natural range, especially in sites experiencing more continental climate since it will be possible to move the species 200-300 m in altitude and 2-3 degrees in latitude.

Vertical migration of Daphnia represents the best-studied predator-avoidance behaviour known; yet the mechanisms underlying the choice to migrate require further investigation to understand the role of environmental context. To investigate the optimal habitat choice of Daphnia under fish predation pressure, first, we selected the individuals exhibiting strong migration behaviour. The animals collected from the hypolimnion during the daytime were significantly larger, being more conspicuous, and in turn performed stronger diel vertical migration (DVM) when exposed to fish cue. We called them strong migrants. Second, we provided the strong migrant D. pulex with food at high and intermediate (1 and 0.4 mg C l -1 , respectively) levels, which were well above the incipient limiting level and of high quality. They traded the benefits of staying in the warm water layer and moved down to the cold water in response to fish cue indicating fish predation. The availability of food allowed the animals to stay in the cold hypolimnion. However, at the low food level (0.1 mg C l -1 ), which is an additional constraint on fitness, Daphnia moved away from the cold hypolimnion. Poor food condition resulted in strong migrant Daphnia to cease migration and remain in the upper warmer water layer. Although temperature is known to be a more important cost factor of DVM than food, our results clearly show that this is only true as long as food is available. It becomes clear that food availability is controlling the direction of vertical positioning when daphnids experience a dilemma between optimising temperature and food condition while being exposed to fish cue. Then they overlook the predation risk. Thus, the optimal habitat choice of Daphnia appears to be a function of several variables including temperature, food levels and fish predation.

The objective of this study was to investigate development of an efficient in vitro tissue culture system for saffron (Crocus sativus L.) complete with roots and corms. In indirect organogenesis, Murashige and Skoog (MS) media with 3% (w/v) sucrose, 100 mg L−1 ascorbic acid, and the combination of 0.25 mg L−1 2,4-dichlorophenoxyacetic acid (2,4-D) and 1 mg L−1 6-benzylaminopurine (BAP) were best for callus initiation and growth while 1.5 mg L−1 BAP was excellent for high rate of adventitious shoot formation. 1 mg L−1 indole-3-butyric acid (IBA) was more preferable for adventitious corm and root initiation as well as growth. Overall, 64% rooting and 33% corm production rates were achieved in indirect organogenesis. In direct organogenesis, MS medium supplemented with 3 % sucrose, 100 mg L−1 ascorbic acid and 1 mg L−1 BAP was optimum for shoot growth. While 1 mg L−1 IBA was best for adventitious corm formation, 2 mg L−1 IBA promoted adventitious root initiation and growth. Overall, 36% and 57% of explants had corm and contractile root, respectively. The high rates suggest that efficient tissue culture system could be achieved for mass propagation and ex situ conservation of threatened saffron genetic resources.