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Sequence analysis of two tandemly linked Em genes from wheat.

DNA sequences are presented for two members of the wheat Em gene family. The sequences correspond to the two linked genes at the Xem-1AL locus. Comparisons of these sequences with that of another wheat Em gene and two Em cDNA clones reveals substantial homology within the protein-coding regions, and the presence in the 5′-flanking regions of the genomic sequences of motifs characteristic of ABA-responsive cis-acting elements.

Impact of food concentration on diel vertical migration behaviour of Daphnia pulex under fish predation risk

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.

Improved in vitro micropropagation method with adventitious corms and roots for endangered saffron

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.

Phylogeny of cultivated and wild wheat species using ATR–FTIR spectroscopy☆

Within the last decade, an increasing amount of genetic data has been used to clarify the problems inherent in wheat taxonomy. The techniques for obtaining and analyzing these data are not only cumbersome, but also expensive and technically demanding. In the present study, we introduce infrared spectroscopy as a method for a sensitive, rapid and low cost phylogenetic analysis tool for wheat seed samples. For this purpose, 12 Triticum and Aegilops species were studied by Attenuated Total Reflection-Fourier Transform Infrared (ATR-FTIR) spectroscopy. Hierarchical cluster analysis and principal component analysis clearly revealed that the lignin band (1525-1505 cm(-1)) discriminated the species at the genus level. However, the species were clustered according to their genome commonalities when the whole spectra were used (4000-650 cm(-1)). The successful differentiation of Triticum and its closely related genus Aegilops clearly demonstrated the power of ATR-FTIR spectroscopy as a suitable tool for phylogenetic research.

The effect of hybrid vigor on callus induction and plant regeneration from mature embryo culture of barley (Hordeum vulgare)

The influence of hybrid vigor on callus induction, callus weight, regeneration capacity of callus, culture efficiency and number of regenerated plants from mature embryo cultures of winter barley (Hordeum vulgare L.) hybrid was studied. A total of 15 F1 hybrids and their parents were used for mature embryo culture. The statistical analysis of the results revealed that positive heterosis was noticed for all these characters except for callus weight. Plants regenerated in vitro were successfully established in soil.

Genetic variation in cold hardiness and phenology between and within Turkish red pine (Pinus brutia Ten.) populations: implications for seed transfer.

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.

The Effect of Seed Size on Tissue Culture Response of Callus from Endosperm-supported Mature Embryos of Barley (Hordeum vulgare L.)

Although immature embryos are the most suitable explants to regenerate cereals, their limited availability throughout the year hampers frequent experimentation. In order to circumvent this problem, endosperm-supported mature embryos, which are available throughout the year, are proposed for utilization in cereal tissue culture studies. In the present study, the effect of seed size on in vitro seed germination, seedling growth, callus induction and plant regeneration, as well as the relationships between these parameters, were investigated in three barley (Hordeum vulgare L.) genotypes. Seeds were designated as large or small for each genotype and seed germinations were achieved in Petri dishes between two sheets of pre-wetted filter paper. Germination percentages of seeds, seedling growth rates, shoot and root lengths, and seedling fresh and dry weights were examined. Mature embryos from imbibed and dehulled seeds were aseptically moved slightly with a scalpel. For callus induction, 8 mg 1−1, 2,4-D dissolved in water, and for plant regeneration, hormone-free MS medium, was utilized. Highest values with respect to seed germination percentage, seedling growth, callus induction and plant regeneration were obtained using large seeds. Rooting of regenerated shoots and plantlet recovery were also successfully achieved. Based on the significant positive correlations observed between all parameters, we concluded that cultures derived from endosperm-supported mature embryos within large seeds should be employed for achieving superior tissue culture response.

Phylogenetic relationships among Triticum L. and Aegilops L. species as genome progenitors of bread wheat based on sequence diversity in trnT-F region of chloroplast DNA

Cultivated wheat, (Triticum aestivum L.), is one of the most important food crops in the world. The Aegilops L. genus is frequently utilized by plant breeders for improving the current wheat cultivars due to their close relationships. Therefore, understanding the phylogenetic relationships among the species of these genera is not only valuable for plant taxonomy, but also for plant breeding efforts. The presented phylogenetic analysis was based on the sequences of trnT-F chloroplast DNA containing three non-coding sub-regions. Twelve genotypes belonging to four species of Triticum L. genus and twenty-four genotypes belonging to eight species of Aegilops genus were used in the current study. The results postulated a close genetic relationship between diploid Aegilops species containing the BB genome and polyploid Triticum species. With the exception of Aegilops cylindrica Host (CCDD), all other Aegilops species having the CC genome were alienated from Aegilops speltoides Tausch (BB) and clustered together. These two clusters joined by a third cluster including the AA genome containing diploid Triticum species.