Pawel Wojcik

Effect of Calcium and Boron Sprays on Yield and Quality of “Elsanta” Strawberry

Abstract The aim of the experiment was to examine the effects of foliar applications of calcium (Ca) and boron (B) on yield and fruit quality of “Elsanta” strawberries grown on a sandy loam soil with low status of available B. The study was conducted in 1999–2000 at a commercial strawberry plantation in Central Poland. Cold‐stored strawberries were planted in 1998 at a spacing of 0.25 × 0.8 m. The following treatments were applied: (i) five sprays of Ca as CaCl2 at a rate of 1.5 kg Ca ha−1 spray−1 with addition of Tween 20 adjuvant at 0.1%; the first spray was performed at the petal fall stage and the next at 5‐day intervals; (ii) three sprays of B as Borvit material at a rate of 160 g B ha−1 spray−1 at the beginning of flowering and 5, and 10 days later; (iii) sprays of B and Ca as in the combination of (i) and (ii). Plants sprayed with water served as the control. Results showed that fruit and leaves from Ca‐treated plants had increased Ca concentrations. Sprays with B increased status of this microelement in fruit and leaf tissues. Treatments did not affect total and marketable fruit yield, mean berry weight, the number deformed fruit, soluble solids concentration and titratable acidity of fruit at harvest. Fruit sprayed with Ca or B plus Ca were firmer and more resistant to Botrytis rot at harvest and after 3 days of holding at 18°C compared to those of control plots. Moreover, sprays of Ca or B plus Ca increased soluble solids concentration and titratable acidity of fruit after 3 days of holding at room temperature. These results indicate that sprays of CaCl2 with addition of Tween 20 should be recommended to improve quality and shelf‐life of strawberry fruit, particularly in proecological production where application of fungicides is restricted.

Impact of Boron on Biomass Production and Nutrition of Aluminum‐Stressed Apple Rootstocks

Abstract The aim of the experiment was to examine the effect of boron (B) on biomass production and nutrition of aluminum (Al)‐stressed apple (Malus sp.) rootstocks. The study was carried out under greenhouse conditions on Polish rootstock (P22) and Malling 26 (M.26) planted singly into 1‐L plastic pots filled with perlite and supplied with Hoaglands medium at pH 4.5 without or with Al (100 µM as AlCl3). Boron was added into the Al‐containing medium at 20, 40, or 60 µM whereas into the medium without Al only at 20 µM as boric acid. The results showed that the presence of Al in the medium reduced biomass production of P22 and M.26 rootstocks by 22% and 41%, respectively. Rates of uptake and translocation of phosphorus (P), magnesium (Mg), and calcium (Ca) to aerial plant parts were decreased for Al‐treated rootstocks. Aluminum‐stressed P22 rootstocks grown in nutrient solution at 40 and 60 µM B had higher dry weight of leaves and roots, and also higher ability to take up P, Mg, and Ca and lower Al than those grown in the presence of Al at 20 µM B in the medium. Rates of absorption and transport of B to aerial plant parts corresponded with B level in the medium. These results suggest that on acid soils with high Al availability, supra‐optimal B concentrations in soil solution (40–60 µM) can prevent/alleviate Al toxicity in apple trees grafted on P22 rootstocks.

GROWTH AND NUTRITION OF M.26 EMLA APPLE ROOTSTOCK AS INFLUENCED BY TITANIUM FERTILIZATION

The objective of this study was to examine the effect of different mode of titanium (Ti) fertilization on growth and nutrition by M.26 EMLA apple rootstock (Malus spp.) grown in three soils with diverse physical and chemical properties. Soils were taken from Warszawa, Grojec and Brzezna regions (fruit growing regions) of Poland. The experiment was carried out during 120 days in a greenhouse. The following treatments were applied: soil Ti fertilization at a rate of 2 and 4 mg Ti per plant and four- and eight-times Ti sprays at a rate of 0.5 mg Ti per plant in each spray. Titanium was applied as TiCl4. Plants unfertilized with Ti served as control. Titanium sprays increased levels of this element in leaf and stem tissues. Soil Ti applications had no effect on Ti concentrations in plant tissues except plants grown in Warszawa soil where root tissue had higher Ti status compared to those of control plants. Foliar Ti applications enhanced plant dry matter and levels of phosphorus (P), iron (Fe), manganese (Mn), and zinc (Zn) in leaf tissues only in Brzezna soil. Leaves of plants sprayed with Ti grown in Brzezna soil were greener and had higher concentrations of Fe2+ and chlorophyll than those of control plants. These results suggest that the primary reason for higher biomass in plants sprayed with Ti was higher leaf Fe2+ level, which enhanced chlorophyll synthesis and uptake of P, Fe, Mn, and Zn.

Dabrowicka prune fruit quality as influenced by calcium spraying

The aim of this experiment was to examine the effect of spraying with different calcium (Ca) materials on prune (Prunus domestica L.) fruit quality. The experiment was conducted in 1996–1998 in Central Poland on ‘Dabrowicka Prune’ trees, grafted on Myrobalan seedlings (Prunus divaricata). Trees were planted in spring 1987 at a distance of 4×4 m on a sandy loam soil with low organic matter and high phosphorus (P), potassium (K), and magnesium (Mg) concentrations. Prune trees were five times sprayed with Ca using CaCl2, Wuxal Calcium, and Stopit materials. In each spray CaCl2, Wuxal Calcium, and Stopit materials were applied at rate of 5, 5, and 10 kg ha−1, respectively. The first spray was applied 10 days after full bloom and four next ones at 8-day intervals. Trees unsprayed with Ca served as control plots. The results showed that Ca sprays had no effect on prune fruit yield and mean fruit weight. Only spraying with Wuxal Calcium enhanced levels of nitrogen (N), Mg, and Ca in leaf and fruit tissues. At harvest, ‘Dabrowicka Prune’ fruit sprayed with Wuxal Calcium had higher soluble solid concentration and titratable acidity and were firmer and more resistant to infection by Monilinia spp. than control fruits. Spraying with the tested Ca materials had no influence on sensitivity of prune fruit to splitting. These results indicate that Ca sprays in plum orchards may be beneficial treatment improving fruit quality.

VIGOR AND NUTRITION OF APPLE TREES IN NURSERY AS INFLUENCED BY TITANIUM SPRAYS

The aim of the experiment was to examine the effect of sprays with titanium (Ti) on growth and nutrition of apple (Malus domestica Borkh.) trees in nursery. The study was carried out in 2000 on “Jonagold”, “Elstar”, and “Szampion” cultivars budded on M.9 EMLA or M.26 EMLA (Malus sp.) rootstocks. Maiden trees were sprayed six times with TiCl4 or Titanit material (Ti-ascorbate) at rates of 1 and 2 g Ti ha−1 spray−1, respectively. Plants sprayed with water served as the control. The results showed that sprays with TiCl4 had no effect on vigor of maiden trees, development of root system, nutritional status, or level of Ti in leaves. Regardless of the rootstock used, sprays with Titanit material improved vigor, nutritional status, and level of Ti in leaves of “Jonagold” and “Elstar” maiden trees. “Szampion” one-year-old trees having high concentrations of microelements in leaves did not respond to Titanit sprays. These results suggest that under conditions of limited uptake of micronutrients such as iron (Fe), manganese (Mn), zinc (Zn), and copper (Cu) by plants, sprays with Titanit material can be beneficial in improving vigor of maiden apple trees.

EFFECT OF CALCIUM CHLORIDE SPRAYS AT DIFFERENT WATER VOLUMES ON “SZAMPION” APPLE CALCIUM CONCENTRATION

The aim of the study was to examine the effect of calcium chloride sprays at different water volumes on ‘Szampion’ apple calcium (Ca) concentration. Apple trees were sprayed with CaCl2at a rate of 7 kg ha−1 using 250, 500, 1000, and 1500 L of water which represents: 2.8, 1.4, 0.7 and 0.5% CaCl2 solution, respectively. Sprays with CaCl2 were applied 6, 4, and 2 weeks before fruit harvest by a directed air-jet sprayer with radial fan. Fruit Ca concentrations were determined from the bottom (to 1.5 m height), middle (from 1.6 to 2.3 m height) and top (from 2.4 to 3.0 m height) of tree. The trees unsprayed with Ca served as a control. The study showed that such treatments did not injure leaves and fruit. Efficacy of CaCl2 sprays at studied water rates in increasing fruit Ca concentration was similar. Apples sprayed with Ca from the middle and bottom of tree canopy had higher Ca concentrations than control fruit. Leaf Ca applications at all water volumes had no effect on fruit Ca concentration from tree canopy top, however, laboratory study indicated that apples from this zone had ability to take up exogenous Ca. It was also found that young ‘Szampion’ fruitlets took up clearly less exogenous Ca as compared to mature fruit, which suggests that Ca sprays of this cultivar should be performed mainly at late apple development stages.

Response of Primocane-Fruiting ‘Polana’ Red Raspberry to Boron Fertilization

ABSTRACT The objective of this study was to examine the response of red raspberry to boron (B) fertilization. The experiment was carried out during 2002–2003 in a commercial plantation in central Poland on primocane-fruiting ‘Polana’ raspberries planted on a sandy loam soil with low status of organic matter and hot water-extractable B. Raspberries were fertilized with B via foliar or soil application. Foliar B sprays were made four times per season: two weeks before flowering, at the beginning of blooming, and three and six weeks later. In each spray treatment, B was used at a rate of 0.1 kg ha−1. Soil B was applied at the stage of bud break at a rate of 1 kg ha−1. Plants untreated with B served as a control. The results showed that B fertilization, regardless of application mode, increased flower and leaf B concentrations, fruit set, and berry yield. Fruit of B-fertilized plants were firmer, and had higher soluble solids concentrations and numbers of drupelets than those of the control plants. Boron fertilization had no effect on plant vigor, mean berry weight, and titratable acidity of fruit. The obtained results indicated that on coarse-textured soils with low B status, soil or foliar B application should be recommended in red raspberry cultivation to increase yield and improve berry quality.

BORON ANALYSIS IN TISSUES BEFORE APPLE TREE BLOOM CAN BE USED TO ASSESS BORON NUTRITIONAL STATUS

The aim of this study was to examine relationships between boron (B) concentrations in flower buds, spur leaves, and flowers and B in leaves of one-year-old shoots. The experiment was carried out during 1997–1999 in the Experimental Orchard of the Research Institute of Pomology and Floriculture in Skierniewice, Poland on mature “Jonagold” and “Gala” apple (Malus domestica Borkh.) trees grafted on 11 and 10 rootstocks, respectively. Flower buds were collected at the stage of their bursting, spur leaves and flowers at the stage of pink bud, and leaves of one-year-old shoots 80 days after full bloom. The results showed that B status in plants was distinctly influenced by rootstock used. Boron levels in the studied organs were relatively stable throughout the years. Highly significant correlation was found between B in buds and flowers and B concentration in leaves of current-season shoots. In the case of “Jonagold” cultivar, correlation coefficient values between B in spur leaves and B in leaves of one-year-old shoots were also high, although they were lower than for relationships between B in buds and flowers and B in leaves of current-season shoots. For “Gala” cultivar, only in two out of three years were correlation coefficients between B in spur leaves and B in leaves of one-year-old shoots highly significant. According to regression models, optimum B levels in flower buds, spur leaves, and flowers are 17.1–33.3, 19.4–32.2, and 14.2–32.6 mg kg−1 for “Jonagold” and 7.1–20.5, 27.2–32.8, and 8.2–29.0 mg kg−1 for “Gala” cultivar. The results indicate that studied plant parts can be used to predict B nutritional status of apple trees and consequently fertilization with this element.

Effect of Boron Fertilization on Sweet Cherry Tree Yield and Fruit Quality

ABSTRACT The goal of the study was to examine response of sweet cherries (Prunus avium L.) to boron (B) fertilization. The experiment was conducted during 2003–2004 in Central Poland on mature ‘Buttners Red’ sweet cherry trees planted on a sandy loam soil with low B availability. Trees were soil-or foliar-fertilized with B. Soil B application was made at a rate of 2 kg ha−1 at the bud-burst stage. Foliar B sprays were performed: (1) in the spring, at the stage of white bud, beginning of flowering, and petal fall and (2) in the fall, approximately four to five weeks before the natural leaf fall. In each of spring spray treatments, B was applied at a rate of 0.2 kg ha−1 and in the fall at a rate of 0.8 kg ha−1. Trees untreated with B served as a control. The results showed that B fertilization had no effect on vigor and yield of sweet cherry trees despite increased concentration of this microelement in flower and leaf tissues. Mean fruit weight, titratable acidity, and fruit sensitivity to cracking also were not influenced by B fertilization. Fruits of B-fertilized trees, regardless of the method of its application, had higher concentrations of soluble solids and anthocyanins than did control plants. It is concluded that under conditions of this experiment, B fertilization can be recommended in sweet cherry culture to improve fruit quality and their appearance.

Response of Black Currant to Boron Fertilization

ABSTRACT The objective of this study was to examine the reproductive and vegetative response of black currant to soil and foliar applications of boron (B). The experiment was carried out during the 2001 and 2002 seasons in a commercial plantation in central Poland on mature ‘Ojebyn’ black currant planted on a sandy loam soil with low status of hot-water-soluble B. Black currant bushes were foliar or soil supplied with B (as boric acid). Foliar B sprays were made on the same bushes 3 times per season (2 weeks before flowering, at the beginning of blooming, and at petal fall) at a rate of 0.2 kg ha−1 in each spray treatment. Soil B was applied at a rate of 2 kg ha−1 at the bud break stage. Bushes untreated with B served as the control. The results showed that vigor of black currant bushes, weight of 100 berries, and soluble solids concentration and titratable acidity of fruit were unaffected by B fertilization. Foliar B sprays increased B concentrations in flowers and leaves, and also enhanced the fruit set and as well as cropping of black currants. Soil B application enhanced leaf B status but had no effect on flower B level and plant yield. These results indicate that foliar B sprays applied at or around the time of flowering should be recommended for black currant plantations to increase productivity of plants containing an insufficient flower B level.