The focus of our research was to evaluate different apples cultivars in terms of their biological properties and bioactive compounds content, and determine the levels of their resistance (or susceptibility) to fire blight. The properties of 10 scab-resistant apple cultivars were examined on the Žiča monastery estate (West Serbia) during the period from 2011 to 2015. The biological and chemical properties such as firmness, maturity stage, total soluble solids, total acids, total and reducing sugars, ascorbic acid content and surface blush of apple fruits were monitored. Various phenolic compounds in the tested samples were tentatively identified by LC-MS analyses. A study of generative properties included: number of flower buds, fruit mass and width, crop load, yield efficiency and yield. During the period of blooming and intensive shoot growth, artificial inoculations were carried out. For each cultivar, a fire blight score was determined by dividing the average length of necrotic tissue by the average total shoot length. In the study period, the cultivars ‘GoldRush’ (41.1 t ha−1) and ‘Florina’ (35.9 t ha−1) produced the highest yields, and the cultivars ‘Discovery’ (19.0 t ha−1) and Selection 25/63 (15.1 t ha−1) the lowest. The cultivar ‘William’s Pride’ produced the largest fruits, with an average fruit mass of 206.8 g. The earliest harvest period was recorded for the cultivar ‘Discovery’ (end of July), and the latest for the cultivar ‘GoldRush’ (beginning of October). The cultivar ‘Enterprise’ had the highest value of total phenols (432.2 mg 100 g
−1 FW), while the cultivar ‘Topaz’ had the highest value of total flavanols (145.2 mg 100 g−1 FW). The highest degree of susceptibility to fire blight was found in Selection 25/63, and the greatest resistance was manifested by the cultivar ‘GoldRush’. In the five-year study period, the cultivars ‘GoldRush’, ‘Rewena’ and ‘Enterprise’ exhibited better bio-chemical properties and higher levels of resistance to fire blight than the remaining cultivars.
The aim of the study was to evaluate the suitability of rootstock and cultivar combinations for high density orchards in northern climate conditions like in Latvia. In 2009, a trial was established with rootstocks M.9 and B.396 in combination with seven cultivars. The density of trees reached 2500 trees per 1 ha. The yields and the observed yield efficiency of all cultivars during the first four production years were larger on rootstock B.396. Also, average trunk diameter was slightly larger on this rootstock. On both rootstocks cultivars, ‘Gita’ and ‘Ligol’ had larger part of total yield formed on previous year shoots. These cultivars had more vigorous trunks as well. In the orchard at the given density, on both rootstocks thinner trunks and smaller yields were observed for cultivars with poor branching, like ‘White Transparent’ and ‘Konfetnoye’. ‘Rubin’ (Kazakh cv.) had low yield, this cultivar produces very large fruits on the ends of shoots. Lower average yields were also obtained for cultivars that produce fruits on spurs of older branch sections, like ‘Antei’ and ‘Kovalenkovskoye’. Summer cultivar ‘Konfetnoye’ had relatively smaller fruits. Rootstock B.396 and scab resistant cultivar ‘Gita’ showed best performance in the high density orchard.
Two growing systems were compared – slender spindle and modified slender spindle, supplemented with or without additional summer pruning. The trial was carried out in orchard of the apple variety ‘Topaz’ in years 2012–2014. The assessed parameters were: trunk cross sectional area (TCSA), crown volume, number of cuts, dry matter weight of pruned wood, cumulative yield, yield efficiency, and relative occurrence of size classes of fruits. The objective was to confirm the hypothesized advantages of modified slender spindle in the period of increasing yields. Based on statistical analysis there was no significant difference among systems in growth measured by TCSA. Increase in crown cubage was the highest on slender spindle with additional summer pruning. The lowest increase of crown cubage was on modified spindle without summer pruning. Number of winter cuts and similarly dry weight was significantly higher on the modified spindle only in 2013. Additional summer pruning influenced both the above-mentioned parameters. There were no significant differences in cumulative yield and yield efficiency between systems. Similarly, the difference in the occurrence of various fruit size classes was not significant. We conclude that study needs to be extended in order to confirm the suggested trends.
A study of 13 grapevine cultivars was carried out in a vineyard located near Krakow (Poland) in order to identify the most suitable grapevine cultivars for cool climate regions. The vines’ vigour, yield and the yield efficiency index were studied in the years 2010-2013. The grapes were analysed to determine soluble solids content (SSC), titratable acidity, total polyphenol content (TPC) as well as fruit antioxidant activity (FRAP). Moreover, organic acid concentrations (tartaric, malic, citric and ascorbic) were ascertained. Significant fluctuations in yield and quality were caused by variable climatic conditions during the vegetation period, especially before the vintage. SSC varied from 15.7°Brix (‘Swenson Red’) to 20.8°Brix (‘Frontenac’). The highest sugar:acid ratio was measured for ‘Regent’ as well as for ‘Hibernal’ and ‘Muskat Odesskij’ among white grapes. The lowest concentration of tartaric acid was measured for ‘Frontenac’ (1.03 g L-1) as well as ‘Jutrzenka’ (1.76 g L-1). The latter cultivar tended to accumulate one of the highest amounts of malic and citric acid. The highest total polyphenol content along with outstanding antioxidant activity was measured for the following red cultivars: ‘Frontenac’, ‘Leon Millot’ and ‘Marechal Foch’. The most promising cultivars were ‘Seyval Blanc’, ‘Aurora’ and ‘Regent’, which performed well in terms of their moderate vigour, increased fruitfulness and consistently higher yields.
In the field experiment, 8-year-old ‘Sylvia’ and ‘Karina’ sweet cherry trees grafted on ‘GiSelA 3’, ‘GiSelA 5’, ‘Piku 4’and ‘Weiroot 72’ clonal rootstocks were compared with trees of the same cultivars on the standard rootstock F 12/1. The data collected included tree vigour (expressed as trunk cross-sectional area − TCSA), yield, and fruit weight as well as content of soluble solids in fruit.
Based on TCSA, the largest ‘Sylvia’ and ‘Karina’ trees were on ‘F12/1’, and the smallest were on ‘GiSelA 3’. The results revealed that all of the tested rootstocks being compared to ‘F 12/1’, significantly reduced the growth of sweet cherry trees.
‘Sylvia’ trees on ‘GiSelA 5’ and ‘Piku 4’ yielded more than those on ‘F12/1’. The highest cumulative yields of ‘Karina’ were harvested from trees on ‘GiSelA 5’. ‘Karina’ trees on ‘GiSelA 3’, ‘Piku 4’ and ‘Weiroot 72’ performed comparably in cumulative yields to those on ‘F12/1’. Rootstock effects on yield efficiency were consistent between the two cultivars, with the most yield efficient trees on ‘GiSelA 3’, ‘GiSelA 5’ and ‘Weiroot 72’, and the least efficient trees on ‘F12/1’.
Trees of both cultivars grafted on ‘GiSelA 3’ produced significantly smaller fruits than those grafted on ‘F 12/1’. The rest of the rootstocks, tested in terms of an effect on fruit weight (with the exception of ‘Karina’ on ‘Weiroot 72’), had a similar value to ‘F 12/1’. Effects of rootstock on content of soluble solids in fruit were modest and statistically insignificant.
calculated as the product of straw N concentration and straw DM yield. Efficiency ratios of fertiliser N use for treatments receiving fertiliser N were calculated according to Lada et al . (2005) . Recovery efficiency of N (RE N ) = (U F - U 0 ) / F N Agronomic efficiency of N (AE N ) = (Y F - Y 0 ) / F N Physiological efficiency of N (PE N ) = (Y F - Y 0 ) / (U F - U 0 ) Nitrogen use efficiency (NUE) = Y/U where U F and U 0 are total N accumulation (kg N/ha) and Y F and Y 0 are the grain yield (kg DM/ha) in the fertilised and unfertilised treatments