Volume 20 (2008): Issue 1 (June 2008)

The possibility of growing 8 cider apple cultivars on M.26, P 14 and Antonovka seedlings in the climatic conditions of Central Poland was studied over a period of 7 years (1996 - 2003). The results obtained showed that cultivars of cider apples are more susceptible to fire blight than standard cultivars ‘James Grieve’, ‘Wealthy’ and ‘Common Antonovka’. After seven years of growth, the most vigorously growing cultivars on the three rootstocks were ‘Ellis Bitter’ and ‘Major’, and on Antonovka seedlings also ‘Yarlington Mill’ and ‘Harry Masters’ Jersey’. The weakest growth was shown by ‘Ashton Bitter’ and ‘Michelin’ on all three rootstocks. Trees of cider cultivars ‘Dabinett’, ‘Michelin’, ‘Ashton Bitter’ and ‘Chisel Jersey’ were similar in size to standard cultivar ‘James Grieve’. After the seven-year period, the highest cumulative yields were obtained from ‘Dabinett’, ‘Chisel Jersey’ and ‘Yarlington Mill’ grown on all three rootstocks. A high cumulative yield was also obtained from ‘Major’ grafted on M.26 and P 14 and ‘Michelin on P 14 and Antonovka seedlings. ‘Dabinett’, ‘Major’ and ‘Chisel Jersey’ were high productive cultivars and can be recommended for growing on P 14 and Antonovka seedlings in commercial orchards in Poland.

The studies conducted in the years 2004 - 2006 in a production orchard in the habitat conditions of the Wyżyna Sandomierska showed that the trees budded on Mazzard seedling grew more strongly than on Colt rootstock. No significant differences were observed between the rootstocks as for the trunk thickness and the crown size of young trees planted in 2001. In the group of trees planted in 1996, which were in the period of full fruiting, the crowns of trees budded on Mazzard seedling were significantly bigger than on Colt rootstock. No significant differences were found in the yielding of trees grafted on Mazzard seedling and Colt rootstock. Considerable differences in the yielding between the studied years in the group of older trees point to a big influence of the weather on the fruiting of cherry. A significant decrease of the yield in 2005 was caused by spring ground frost, while in 2006 by frozen short shoots in winter. ‘Regina’ is a valuable cultivar for production planting in the Wyżyna Sandomierska. It begins the fruiting period late (the first commercial yield in the fifth year after planting); however, it gives attractive fruits, resistant to cracking in the rain. ‘Regina’ yielded abundantly on both examined rootstocks.

The objective of the research was to assess a grade of parthenocarpic fruit and fruitsetting following cross-pollination and self-pollination in pepino plants (Solanum muricatum Ait.). An experiment with six pepino clones of different origin was set up in glasshouse conditions. Experimental clones were subjected to the following treatments: self-pollination, cross-pollination, and emasculation without any control. The tested clones of pepino were self-pollinated, capable of cross pollination and facultative parthenocarpic. The differences between clones in their ability to parthenocarpic fruit formation were observed. The ripening period of pepino fruits and their weight depended on a clone.

The pathogenicity of A. alternata, F. culmorum, F. oxysporum, F. solani, P. irregulare, and R. solani isolated from oats, spring vetch, and tancy phacelia mulch soil to Scorzonera hispanica L. in the conditions of a growth chamber was studied. The pathogenicity of these microorganisms was established on the basis of the number of emerged plants and their healthiness. The studied species considerably decreased the emergencies and healthiness of the seedlings, e.g. necrosis of sprouts and roots. Differentiated harmfulness of particular microorganisms isolates was observed within a given species. The isolates of P. irregulare and F. oxysporum proved to be the most severe for the seedlings, while A. alternata the least.

The influence of the cultivation time (spring-summer and autumn) and the kind of cultivation (on rockwool and peat) on the fertility of pollen coming from three successive trusses were studied for six different pepino clones. The fertility was defined in vitro as the capacity of pollen for germinating. The average capacity of pollen germination ranged in the studied clones from 10 to 15%. These clones displayed the highest pollen fertility in an autumn cultivation, comparing to a spring-summer one. Higher rate of pollen fertility was observed during a springsummer cultivation on first trusses in most of the clones studied. The pollen of all plants grown on rockwool was more fertile, comparing to the cultivation on peat substrate. High differences in pollen fertility of the clones were obtained

In the present studies, an attempt has been made to develop a method of liquid nitrogen preservation of plant explants propagated in vitro in the laboratory of the Department of Ornamental Plants, of Agricultural University in Kraków: shoot apical and axillary meristems of Rosa ‘New Dawn’, somatic embryos of snowdrops Galanthus nivalis L. and G. elwesii Hook, and gametophyte of Phlebodium aureum (L.) J. Sm. (golden polypody). After encapsulation of plant material, it was dehydrated by quick method (capsules were placed in liquid media containing 0.75 M sucrose for 18 h) or by gradual method (capsules were transferred to liquid solutions of media with increasing sucrose concentrations from 0.3 M to 1 M for consecutive 7 days). Moreover, some explants for cryopreservation were treated with the medium containing elevated sucrose level (0.25 M) for 8 weeks

A virus was isolated from Lavandula angustifolia Mill. plants exhibiting yellow mottling and distortion of leaves. After mechanical inoculation it induced in the major part of used test plants symptoms characteristic for Cucumber mosaic virus (CMV). Its standard properties regarding the stability in crude plant sap were as follows: longevity in vitro 1-2 days, thermal inactivation point 55-60°C, dilution end point log10minus 3 - 4. The virus reacted positive with diagnostic antiserum against CMV in DAS-ELISA test. RT-PCR reaction revealed similarity between the investigated isolate and the isolate of CMV from the Netherlands belonging to subgroup II. In the light of the foregoing facts the isolated pathogen can be identified as the Cucumber mosaic virus and Lavandula angustifolia may be regarded as its natural host.

In the years 2005 - 2006 studies were conducted in a growth chamber and a vegetation hall which compared tolerance to NaCl salinity of seeds and plants of some lawn grasses. The effect of sodium chloride salinity on the germination of 4 species of grasses i.e. Lolium perenne cv. ‘Info’, Festuca rubra cv. ‘Audio’, Agrostis capillaris cv. ‘Niwa’, Poa pratensis cv. ‘Alicja’ and 4 cultivars of Lolium prenne - ‘Nira’, ‘Stadion’, ‘Ronija’, ‘Darius’ was studied. The grass seeds germinated in Petri dishes, in darkness, at the temperature of 24°C. Besides the control, 3 levels of salinity were used in the studies: 100, 200 and 300 mM NaCl. The obtained results demonstrated that the growing level of salinity in the environment significantly decreased the germinating speed, the number of the produced roots, the length of the longest root, and the length of the coleoptile in the seedlings of all studied grass species. Lolium perenne seeds tolerated salinity the best, and next - in a diminishing sequence - those were the seeds of Festuca rubra, Agrostis capillaris and Poa pratensis. However, the obtained data showed that tolerance to salinity of the analyzed cultivars of Lolium prenne decreased in the following sequence ‘Ronija’ > ‘Stadion’ > ‘Nira’ > ‘Darius’.

In a vegetation hall tolerance to NaCl salinity of these 4 cultivars of Lolium perenne in the first year growth was compared. The plants grew in pots of 2 dm³ filled with a mixture of universal earth and river sand (3:1 / v:v) with the soil moisture of 70% and 3 levels of salinity: 0, 50, and 100 mM NaCl. The obtained results demonstrated that in all studied cultivars the increase of the salinity level caused a significant decrease of the yield of the leaf dry weight from the successive grass crops, and an increase of the content of sodium, chloride and free proline in them. The greatest tolerance to NaCl salinity in the group of the studied cultivars was shown by ‘Ronija’, medium tolerance - by ‘Darius’ and ‘Stadion’, and the lowest one - by ‘Nira’. This resulted from the degree of accumulation of Na⁺ and Cl^- ions and proline in those conditions. The cultivars with higher tolerance accumulated fewer osmotically active compounds in the leaves.