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1

Effect of gamma rays on regeneration of adventitious shoots from leaf explants of Dendranthema grandiflora Tzvelev

100%
Zalewska M., Lema-Ruminska J.
Biotechnologia
|
2004
|
issue 2
86-92
EN
Microcuttings of chrysanthemum radiomutants were irradiated in vitro with gamma rays with a dose of 15 Gy. The adventitious shoots' regeneration on MS medium was applied. The medium used was supplemented with plant growth regulators: 2 mg l-1 IAA and 0.6 mg l-1 BAP. An effect of radiation on the numbers of adventitious shoots regenerated from irradiated leaf explants was determined. 'Lady Vitroflora' produced substantially more adventitious shoots per one explant than 'Lady Apricot'. The ionizing radiation clearly reduced leaf explants regeneration capacity. The rate of adventitious shoots regeneration depended on the cultivar and was always higher than that for non-irradiated explants.
2

In vitro organogenesis induction in Sida hermaphrodita Rusby by cort

88%
Przyborowski J. A., Szczukowski S., Tworkowski J., Stolarski M.
Biotechnologia
|
2004
|
issue 2
131-136
EN
Sida hermaphrodita Rusby belongs to the Malvaceae family. It is a perennial plant. Biomass obtained from sida plantations may constitute excellent raw material for renewable energy production. Sida hermaphrodita Rusby reproduces generatively, but its vegetative reproduction is also possible by root-cuttings, division of the underground part into particular roots, or cuttings obtained from green above-ground shoots. Sida seeds should be sown not earlier than after one year of storage, because immediately after harvest the percentage of germinated seeds is as low as 2%, after twelve months of storage 77.5%, to drop in successive months. Moreover, due to their hardness, sida seeds require special treatment. Therefore, an attempt was made at developing a method for in vitro micro-reproduction of sida plants, as an alternative method of seed material production. Two kinds of explants were used in the experiment, i.e. leaf discs 8 mm in diameter and 3 mm fragments of leaf stalks. The growth regulators were added to the MS medium in combinations, i.e.: IAA + kinetin; IAA + kinetin + BAP; TDZ + 2.4-D; 2ip + 2.4-D. The callus formed was crumbled and transferred to two kinds of medium: MS without growth regulators and MS with kinetin, NAA, GA3 and 40 g l-1 of sucrose. The most intensive growth of callus was observed on media containing 2ip and 2,4-D, but the highest number of roots and developing shoots was obtained on MS medium without fitohormones.
3

Resistance to Melampsora larici-epitea leaf rust in Salix: analyses of quantitative trait loci

75%
Ronnberg-Wastljung A.-C., Samils B., Tsarouhas V., Gullberg U.
Journal of Applied Genetics
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2008
|
vol. 49
|
issue 4
321-331
EN
Quantitative resistance of Salix to Melampsora larici-epitea leaf rust was studied in 2 Salix mapping populations. One population was a backcross between a S. schwerinii S. viminalis hybrid and S. viminalis, and the other was an F2 population between S. viminalis and S. dasyclados. A leaf disc bioassay was used to study the components of quantitative resistance (latent period, uredinia number, and uredinia size) to 3 isolates of the leaf rust. The analysis of quantitative trait loci (QTLs) revealed 9 genomic regions in the backcross population and 7 genomic regions in the F2 population that were important for rust resistance, with QTLs explaining 8?26% of the phenotypic variation. An important genomic region was identified for the backcross population in linkage group 2, where QTLs were identified for all resistance components for 2 of the rust isolates. Four of the QTLs had overlapping mapping intervals, demonstrating a common genetic background for latent period, uredinia diameter, and uredinia number. QTLs specific to some rust isolates and to some resistance components were also found, indicating a combination of common and specific mechanisms involved in the various resistance components. Breeding implications in relation to these findings are discussed.
4

Genetic variation in the efficiency of nitrogen utilization and photosynthetic activity of flag leaves among the old and modern germplasm of winter wheat

75%
Gorny A. G., Garczynski S., Banaszak Z., Lugowska B.
Journal of Applied Genetics
|
2006
|
vol. 47
|
issue 3
231-237
EN
Genotypic variation in major components of the efficiency of nitrogen utilization and photosynthetic activity of flag leaves among old (released 1881?1963) and modern (released 1969?2003) cultivars of winter wheat was studied in field conditions under varied N fertilization levels (110, 90 and 80 kg N ha?1). Significant genotypic differences were observed for all characters. Their heritabilities ranged from 0.37 to 0.93 and were the lowest for the leaf efficiency of gas exchange, photosynthetic rate, straw N content and the economic index of N utilization efficiency (NUE). Some modern cultivars exhibited an enhanced tolerance to N shortage and several attributes of efficient N utilization (e.g. later senescing and more photosynthetically active flag leaves, increased ability to redistribute N into grains). The genotypes may serve as donors of appropriate characteristics for breeding. The observed cultivar-by-fertilization interactions suggest, however, that evaluations under diverse fertilization regimes may be necessary when searching for improved wheat efficiency and adaptation to less favourable environments.
5

Genotypic and nutrition-dependent variation in water use efficiency and photosynthetic activity of leaves in winter wheat (Triticum aestivum L.)

63%
Gorny A. G., Garczynski S.
Journal of Applied Genetics
|
2002
|
vol. 43
|
issue 2
145-160
EN
Effects of high and reduced NPK nutrition on the genetic variation of components of water use efficiency at the leaf and whole-plant levels were examined in pot-grown old and modern cultivars of winter wheat (Triticum aestivum L.). At the subsequent growth stages, the photosynthetic rate (A), transpiration rate (E), leaf area (LA) and gas exchange efficiency (A/E) were measured on fully developed 4th, 5th, penultimate and flag leaves. At the plant canopy level, the total amount of water transpired was recorded during the whole life cycle to determine the efficiency of water use in the vegetative (WUEveg) and grain (WUEgen) matter formation. Considerable genotypic differences were found for the characters studied. The limited NPK supply caused a decrease in LA, A and A/E, but contributed to an increase in WUEgen. Examined cultivars (C) did not interact with nutrition levels (N) for these characteristics. However, the position of leaves (L) and the C ? L and N ? L interactions significantly affected the variance in leaf photosynthetic characteristics. A and A/E were negatively correlated with LA, and the flag leaves were photosynthetically less active and less efficient per unit area than the lower leaves. The whole-plant components of WUE were found to be more genetically stable than the photosynthetic leaf characteristics. Some modern cultivars tended to form leaves of higher A and A/E than the older ones, and this corresponds with a more efficient use of water in grain formation (WUEgen) of the former. Stay-green duration of flag leaves and harvest index showed positive correlations with WUEgen. However, no close associations were noticed between WUE components and stress tolerance, and the modern cultivars were usually less tolerant to NPK shortage.
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