30 research outputs found
The effect of light intensity on the production of oat (Avena sativa L.) doubled haploids through oat Ă maize crosses
Oat haploid embryos were obtained by wide crossing with maize. The effect of light intensity during the growing period of donor plants (450 and 800 ”mol mâ2 sâ1) and in vitro cultures (20, 40, 70 and 110 ”mol mâ2 sâ1) was examined for the induction and development of oat DH lines. Oat florets (26008) from 32 genotypes were pollinated with maize and treated with 2,4-dichlorophenoxyacetic acid. All the tested genotypes formed more haploid embryos when donor plants were grown in a greenhouse (9.4%) compared to a growth chamber (6.1%). The light intensity of 110 ”mol mâ2 sâ1 during in vitro culture resulted in the highest percentage of embryo germination (38.9%), conversion into plants (36.4%) and DH line production (9.2%) when compared with lower light intensities (20, 40 and 70 ”mol mâ2 sâ1). The results show that the growth conditions of the donor plant and light intensity during in vitro culture can affect the development of haploid embryos. This fact may have an impact on oat breeding programs using oat Ă maize crosses
Obtaining of winter rye (Secale cereale L. ssp. cereale) haploid embryos through hybridization with maize (Zea Mays L.)
The aim of this study was to determine the effect of selected factors on rye (Secale cereale L.) haploid embryo production by the wide crossing method. The study was performed on fifteen winter rye genotypes. This is the first time for rye when besides the genotype, on the enlargement of ovaries and haploid embryo production, such factors as: type of auxin analogues 2,4-dichlorophenoxyacetic acid (2,4-D), 3,6-dichloro-2-methoxybenzoic acid (dicamba) and 4-amino-3,5,6-trichloropyridine-2-carboxylic acid (picloram), and the time between florets emasculation and pollination were investigated. All factors had a significant impact on rye ovary enlargement, however the haploid embryo formation depended only on rye genotype, not on kind of auxin and days between emasculation to pollination. In total, twenty one haploid embryos were formed by six genotypes of fifteen tested. On average, 13.86% (after 2,4-D treatment) to 20.05% (after dicamba treatment) enlarged ovaries per emasculated florets were obtained. Most of the ovaries enlarged when florets were pollinated 4 and 6 days after emasculation. Most of the haploid embryos formed when florets were pollinated 6 days after emasculation. The obtained haploid embryos did not germinate
Chlorophyll a fluorescence parameters in the evaluation of oat DH lines yield components
Chlorophyll a fluorescence can provide insight into the ability of plants to tolerate environmental conditions that can damage photosynthetic apparatus and decrease yield. The aim of the study was to determine the relationship between chlorophyll a fluorescence parameters and yield components of oat DH lines. All DH lines significantly differed in chlorophyll a fluorescence parameters and yield components. The overall performance index of PSII photochemistry (PI), showed the highest variation between DH lines, whereas the lowest had the ratio of variable to maximum fluorescence (Fv/Fm). The highest differences were observed in the number of grains per plant (21.3 to 600). Thousand-grain weight varied from 17.82 g to 41.01 g and the biomass from 8.01 g to 29.31 g. The highest negative correlations were found between Fv/Fm, Area (pool size of electron acceptors from PSII), PI and grain number per plant and biomass. Positive correlations were observed between light energy absorption (ABS/CS), grain number per plant and biomass, as well as the amount of excitation energy trapped in PSII reaction centers (TRo/CS) and biomass. Principal component analysis of chlorophyll a fluorescence parameters, together with yield components, discriminated two oat DH lines groups according to their photosynthetic efficiency and yield
UV-B radiation modifies the acclimation processes to drought or cadmium in wheat
Under natural conditions plants are often subjected to multiple stress factors. The main aim of
the present work was to reveal how UV-B radiation affects acclimation to other abiotic
stressors. Wheat seedlings grown under normal light conditions or normal light supplemented
with UV-B radiation were exposed to drought or Cd stress and were screened for changes in
the contents of salicylic acid and its putative precursor ortho-hydroxy-cinnamic acid, and in
the activity of the key synthesis enzyme, phenylalanine ammonia lyase. Certain other
protective mechanisms, such as antioxidant enzyme activities and polyamines, were also
investigated. PEG treatment under UV-B radiation did not cause wilting, but resulted in more
pronounced salicylic acid accumulation, which may provide protection against drought stress
in wheat plants. In contrast, the high level of salicylic acid accumulation in Cd-treated plants
was not further enhanced by UV-B stress, but resulted in pronounced oxidative stress and the
activation of antioxidant systems and polyamine synthesis. Changes in the levels of phenolic
compounds are accompanied by increased phenylalanine ammonia lyase activity in the roots,
but not in the leaves. The similar pattern observed for stress-induced changes in salicylic acid
and ortho-hydroxy-cinnamic acid contents suggested that salicylic acid may play a decisive
role via ortho-hydroxy-cinnamic acid. The results indicated that UV-B radiation might have
either a positive or negative impact under the same conditions in wheat, depending on the
type of secondary abiotic stress factor. The protective or damaging effects observed may be
related to changes in the levels of phenolic compounds