The Influence of Planting Substrate on the Fruit Quality Characteristics of Seven Blueberry Cultivars

Bulletin UASVM Horticulture, 67(1)/2010 Print ISSN 1843-5254; Electronic ISSN 1843-5394 The Influence of Planting Substrate on the Fruit Quality Characteristics of Seven Blueberry Cultivars Mihai IANCU, Irina ANCU, Silvia NICOLAE, Claudia NICOLA Research Institute for Fruit Growing Pitesti, O.P.1, C.P.73, 110006, Arges, Romania; irinaancu80@yahoo.com, office@icdp-pitesti.ro Abstract. To obtain good yields, the highbush blueberry (Vaccinium corymbosum) needs special soil conditions with high organic matter content and optimal ph values, ranging from 4.8 up to 5.5. To obtain such properties which are close to those from above, on an alluvial soil with low humus content, poorly gleyed, situated on 3 rd terrace of the Doamnei River, an experiment was organized during 2006-2008 at the Research Institute for Fruit Growing Pitesti Maracineni. The experiment had the following scheme: A Factor- cultivar with seven graduations: a 1 - Simultan, a 2 -Delicia, a 3 -Lax, a 4 - Compact, a 5 -Augusta, a 6 -Azur a 7 -Blueray; B Factor-planting substrate with 3 graduations: b1-5 kg peat+5kg manure; b2= 10 kg coniferous litter; b3= 5kg peat+5 kg manure+40 g sulphur powder; C Factor - experimental year, with 3 graduations. On average for 3 planting substrates and 3 experimental years, the cultivar Simultan registered a significant increase by 19-28% in soluble solids (% Brix), by 15-27% in dry matter content, by 19-36% in ash content, by 12-21% in total sugar content, by 19-36% in ph value, by 7-28% in K content, versus the others six studied cultivars. On average on seven studied cultivars and 3 experimental years, the b1 and b3 treatments, except for ph values, registered significant higher values of contents of all fruit quality characteristics, versus b2 one. Keywords: peat, manure, firmness, total sugar content, soluble solids INTRODUCTION The highbush blueberry is characterized by large berries with intensive dark blue color, high firmness and a pleasant sweet taste. The berries are considered to be one of the most valuable fruit due to their low caloric value (Kupien, 2006) and high antioxidant activity (Prior et al. 1998; Mainland et al. 2002). For this reason, this crop is extensively cultivated in the USA and more recently have become a popular commercial crop in many European countries. In Romania, high bush blueberry was introduced for the first time in 1968 at the Research Institute for Fruit Growing Pitesti-Maracineni (Botez et al., 1984). For optimal growth and productivity high bush blueberry needs well drained acid soils (ph H2O 4,8-5,5) with high content of organic matter. In Romania such soils are found on restricted areas. To extend the highbush blueberry culture on large areas with different soils, the ph adjustment and additional organic matter before planting is necessary (Korkak, 1988; Finn et al., 1993). The fruit quality characteristics of highbush blueberry are influenced by many factors out of which the cultivar and growing conditions are very important. The purpose of this study was to evaluate the effects of three planting substrates on the basic fruit quality characteristics of seven highbush blueberry cultivars. With this regard during 2005-2009 an experiment was organized at Research Institute for Fruit Growing Pitesti-Maracineni.. 115

MATERIALS AND METHODS The experiment was located on the 3 rd terrace of the `Doamnei River`. Some data about this experiment were presented in other paper published in these proceedings (Iancu et al., 2010). A subdivided plot design with factorial arrangement 7x3x3 was applied after the folowing scheme: A Factor - cultivar, with seven graduations: a 1 - Simultan, a 2 -Delicia, a 3 - Lax, a 4 -Compact, a 5 -Augusta, a 6 -Azur a 7 -Blueray; B Factor - the substrate applied at planting, with 3 graduations: b 1-5 kg peat+5kg manure; b 2 = 10 kg coniferous litter; b 3 = 5kg peat+5 kg manure+40 g sulphur powder; C Factor- the studying year, with 5 graduations c1-2007; c2-2008; c3-2009. The experiment was organized in 3 replications (2 plants per replication). For quantifying the effects of planting substrate on the fruit quality characteristics, some biometric fruit quality indicators (size index, shape index, calyx cavity, firmness) and basical chemical compounds of fruit including dry weight, ash, soluble solids, total sugar, titrable acidity, ph, phosphorus and potassium were determined. Biometric indicators were determined by measuring each fruit with a calliper. The index size was calculated by formula: (height +large diameter +small diameter)/3, and shape index by the formula: (larger diameter + smaller diameter)/ 2 height (after Botu and Botu, 1997). The fruit firmness was determined with a SHIMPO DFS apparatus on 25 randomly selected berries from each replication. The dry weight was determined by gravimetric method. Ash content was determined by combustion of aliquat (10 g of fresh fruit tissue) at 550-600 C. Soluble solids content was determined in berry juice obtained from 10 fruits from every replication, by means of digital refractometer (PR Series). The total sugar content was determined by Fehling Soxhlet titrymetric method, organic acid content was determined by titration. Phosphorus and potassium contents were determined by flamefotometer-type Flapho 4). The results were statistically calculated by analysis of variance method and the Tukey test ( 0,05) was applied when significant differences resulted. RESULTS AND DISCUSSION 1. The influence of planting substrate on some quality fruit characteristics of seven blueberry cultivars (Tab. 1). On average, for three planting substrates and three research years, the Simultan cultivar registered a significant increase by 19-28% of soluble solids ( Brix), by 15-27% of dry weight content, by 19-36% of ash content, by 12-21% of total sugar content, by 19-36% of ph value, by 7-28% of K content, versus the others six studied cultivars. On average for the seven studied cultivars and three research years, the b1 and b3 treatments, versus b2 one, except ph values, registered significant higher contents of all studied fruit quality characteristics. Under in the same conditions, the application of the 3 treatments determined a significant increase by 6% of ash content, by 4% of total sugar content, by 7% of the phosphorus content and by 5% of the potassium content, versus b1 treatment. In exchange, the application of b1 treatment determined a significant increase by 4% of the calyx cavity and by 5% of the firmness, versus the b3 treatment. The significant decreasing of firmness value by applying sulphur is considered as a negative effect because the higher firmness value implies a better suitability for transportation. On average for seven cultivars and three planting substrates the annual values of the 12 fruit quality characteristics showed significant differences between them within the period of investigation 2. The influence of three planting substrates on some quality fruit characteristics of seven blueberry cvs. 116

On average over the three years of investigation, the seven blueberry cultivars showed significant differences between them within each of three planting substrates for all 12 quality fruit characteristics. The b1 and b3 fertilization treatments significantly varied within each cultivar for five of twelve quality fruit characteristics (size index, ash, sugar, phosphorus and potassium) versus the b2 fertilization treatment. For the other 7 quality fruit characteristics, the three planting substrates significantly varied between them with different intensities (Tab. 2) related to the cultivar. 3. The influence of the study years on some quality fruit characteristics of seven studied blueberry cultivars. On average for the three planting substrates, the seven studied blueberry cultivars significantly varied between them with different intensities within each year of study for all twelve studied fruit quality characteristics. Under the same conditions, for each of the seven studied cultivars, the three years of study significantly varied between them for all twelve studied fruit quality characteristics (Tab. 3) Comparing the dry weight, ash and soluble solids contents of the Blueray cultivar with the values registered at the same cultivar in Poland by Skupien (2006), it is seen that in the our case much higher values were registered. That, probably, both climate and growing conditions allowed to obtain highbush blueberry fruit of better quality. On the other hand, comparing the values of the above mentioned fruit qualities, of Blueray cv. with those of the other six studied cultivars it is seen that in four out of these six cultivars better values were registered. That emphasize a higher value of some quality fruit characteristics for some newly created Romanian cultivars. Among the newly bred cvs., Simultan cv. holds the 1 st place both in terms of good berry quality and high yield (Iancu et al., 2010, proceedings). Application of b1 and b3 planting substrates determined an abvious improvement in almost all fruit quality characteristics, versus b2 treatment. Some authors (Botez et al., 1986, Moore, (1993) quoted by Krzewinska, (2004), Li Yadong et al., (2006), showed that sulphur application is a good way to lower ph and to obtain successful blueberry crops. In this respect, Li Yadong et al. (2006) showed that 1 kg elemental sulphur/m3 application can decrease ph by 2 units, whereas 2kg/m 3 can decrease ph by 2.7-3 units. In our case, The application of 5 kg manure + 5 kg peat+40 g sulphur powder at planting determined a significant increase by 6% of the ash content, by 4 % of total sugar content by 7% of the phosphorus content and by 5% of the potassium content, versus only 5 kg manure + 5 kg peat application at planting. That entirely justifies the application of sulphur powder at planting. CONCLUSIONS 1. On average for three planting substrates and three investigation years, the Simultan cv. registered a significant increase by 19-28% of soluble solids, by 15-27% of dry weight content, by 19-36% of ash content, by 12-21% of total sugar content, by 19-36% of ph values, by 7-28% of K content, versus the other six studied cultivars. 2. On average for seven studied cultivars and the three investigation years the b1 and b3, treatments versus b2 one, except ph values, registered significant higher contents of all studied fruit quality characteristics. 3. On average for the seven cultivars and three planting substrates the annual values of 12 fruit quality characteristics significantly varied between them during the investigation period 117

Influence of planting substrate of some quality fruit characteristics of seven blueberry cultivars Tab. 1 The studied character A,B,C experimental factors graduations a1 a2 a3 a4 a5 a6 a7 5% LSD b1 b2 b3 5% LSD c1 c2 c3 5% LSD 1 12.7 15.3 14.3 14.2 14.2 14.4 14.3 0.42 15.1 12.5 15.1 0.31 12.8 13.5 16.3 0.28 2* 1.41 1.73 1.94 1.95 1.95 1.95 2.03 0.12 2.0 156 1.98 0.08 1.50 1.64 2.41 0.007 3 5.27 5.60 7.93 7.56 6.80 6.23 5.75 0.26 6.92 5.79 6.64 0.14 5.69 6.29 7.37 0.10 4 0.64 0.63 0.56 0.53 0.60 0.60 0.66 0.04 0.63 0.58 0.60 0.02 15.5 15.4 14.7 0.21 5 15.8 13.3 13.0 13.6 13.3 13.3 12.3 0.69 14.0 12.4 14.1 0.28 13.6 13.8 13.9 0.32 6 17.6 15.0 14.3 15.1 15.3 13.9 15.0 0.40 15.4 14.5 15.6 0.26 15.5 15.4 14.7 0.21 7 0.38 0.30 0.28 0.31 0.32 0.29 0.30 0.02 0.32 0.27 0.34 0.01 0.37 0.27 0.30 0.002 8 14.4 12.4 12.9 12.7 12.7 11.9 12.3 0.15 12.8 12.2 13.3 0.11 12.8 12.9 12.6 0.06 9 0.53 1.07 0.54 0.94 0.54 0.59 0.73 0.06 0.72 0.67 0.73 0.03 0.70 0.73 0.69 0.02 10 4.29 3.16 3.53 3.49 3.60 3.23 3.44 0.36 3.53 3.52 3.56 NS 3.26 3.71 3.78 0.09 11 12.9 13.1 13.8 13.5 11.2 11.2 12.8 0.14 12.8 11.4 13.7 0.14 12.4 12.4 13.4 0.12 12 115 104 94 107 98 90 104 4.5 106 88 111 2.25 109 97 100 2.35 The studied character: size index (cm), shape index (cm), calyx cavity (mm), firmness (N), soluble solids (ºBrix), dry weight (%), ash (%), total sugar (%), titrable acidity (% malic acid), ph, phosphorus (%), potassium(%). The A,B,C experimental factors graduations is presented in text at the chapter Material and methods; NS-Non significant at 5% significance threshold *Note: Shape index with value 0.9-1.0 cm indicate round fruit; the value smaller than 0.9 cm oblong fruits; values over 1 cm-flattened fruits (by Botu and Botu,1987) 118

Tab. 2 The influence of three planting substrates on some fruit quality characteristics of seven blueberry cultivars The studied character 1 A factor graduations 5% LSD B factor graduations a1 a2 a3 a4 a5 a6 a7 1 2 b1 13.2 16.0 15.0 15.4 15.5 16.3 14.2 b2 10.5 12.9 12.1 12.9 12.8 12.7 13.4 0.81 0.73 b3 14.4 16.9 15.7 14.3 14.4 14.1 15.4 2 b1 1.7 1.9 2.1 2.2 2.1 2.1 2.0 b2 1.1 1.2 1.4 1.8 1.7 1.8 1.9 0.22 0.21 b3 1.5 2.1 2.3 1.9 2.0 1.9 2.2 3 b1 5.4 6.0 8.8 8.1 7.3 7.0 5.8 b2 4.7 5.1 6.4 7.0 6.1 5.6 5.6 0.37 0.45 b3 5.6 5.7 8.6 7.6 7.0 6.0 5.8 4 b1 0.69 0.65 0.57 0.53 0.66 0.61 0.69 b2 0.64 0.59 0.56 0.50 0.54 0.58 0.67 0.06 0.07 b3 0.60 0.65 0.56 0.58 0.61 0.60 0.63 5 b1 16.5 14.1 13.1 13.7 13.7 13.6 13.3 b2 14.4 12.0 12.6 13.3 11.3 12.2 11.3 0.73 1.19 b3 16.5 13.8 13.2 13.9 14.8 14.0 12.5 6 b1 17.8 15.4 14.7 15.6 15.4 14.2 150 b2 17.4 13.4 13.6 13.9 15.1 13.4 14.8 0.56 0.70 b3 17.8 16.3 14.7 15.8 15.5 14.2 15.1 7 b1 0,40 0,32 0,29 0,32 0,37 0,31 0,31 b2 0.30 0.27 0.23 0.28 0.29 0.25 0.26 0.03 0.03 b3 0.44 0.31 0.33 0.34 0.36 0.30 0.34 8 b1 14.3 13.0 13.1 12.8 12.7 11.9 12.1 b2 13,6 10,9 12,2 12,2 12,5 11,7 11,7 0.11 0.22 b3 15.2 13.3 13.3 13.2 12.8 12.1 13.0 9 b1 0.57 1.11 0.57 0.99 0.53 0.62 0.69 b2 0.53 0.95 0.46 0.86 0.56 0.55 0.76 0.07 0.10 b3 0.49 1.16 0.59 0.97 0.54 0.61 0.76 10 b1 3.94 3.09 3.54 3.52 3.75 3.30 3.54 b2 4.60 3.17 3.58 3.43 3.41 3.05 3.42 0.44 0.62 b3 4.35 3.22 3.47 3.51 3.66 3.35 3.37 11 b1 13.2 13.3 14.2 14.0 11.2 10.9 12.9 b2 10,2 12,4 12,5 12,2 10,5 10,4 11,6 0.37 0.33 b3 15.1 13.5 14.8 14.4 12.0 12.4 13.8 12 b1 118 112 95 114 97 93 109 b2 105 87 85 91 90 71 90 5.9 7.8 b3 124 113 103 115 106 105 113 The studied character: 1-12 The same meanings as in table 1; The significance of A,B factors graduations is presented in text at the chapter `Material and methods`; 5% LSD: 1- A constant factor, B variable factor; 2-B constant factor; A variable factor; NS-Non significant at 5% significance threshold. 119

Tab. 3 Influence of the investigation years of some quality fruit characteristics of seven studied blueberry cultivars (A,C experimental factors interaction) The studied character 1 C factor A factor graduations 5% LSD graduations a1 a2 a3 a4 a5 a6 a7 1 2 c1 11.1 14.3 12.9 12.9 12.6 12.4 13.3 c2 11.9 15.2 13.7 13.6 13.1 12.9 13.8 0.74 0.73 c3 15.1 16.3 16.2 16.1 16.9 17.7 15.9 2 c1 1.15 1.83 1.63 1.40 1.44 1.46 1.60 c2 1.34 205 1.75 1.58 1.56 1.51 1.69 0.19 0.21 c3 1.73 1.32 2.44 2.86 2.86 2.87 2.80 3 c1 4.74 4.74 7.02 6.67 6.13 5.19 5.32 c2 5.36 5.47 7.74 7.43 6.68 5.61 5.77 0.28 0.45 c3 5.70 6.59 9.01 8.66 7.58 7.88 6.17 4 c1 0.71 0.67 0.61 0.58 0.65 0.64 0.72 c2 0.64 0.62 0.55 0.52 0.60 0.58 0.65 0.02 0.07 c3 0.58 0.61 0.54 0.51 0.57 0.57 0.63 5 c1 16.5 13.0 14.0 13.5 12.7 13.9 12.8 c2 16.3 14.5 13.2 14.5 14.7 12.5 11.9 0.84 1.37 c3 14.8 12.8 11.4 12.9 13.1 12.4 11.8 6 c1 18.4 16.1 14.1 16.0 15.1 13.6 15.4 c2 17.5 15.3 14.7 15.4 15.6 14.2 15.0 0.56 0.70 c3 17.0 13.6 14.1 13.9 15.2 14.0 14.6 7 c1 0.40 0.37 0.34 0.38 0.41 0.28 0.43 c2 0.31 0.22 0.29 0.28 0.28 0.28 0.23 0.02 0.03 c3 0.43 0.32 0.21 0.28 0.29 0.30 0.25 8 c1 14.4 12.4 12.6 12.7 12.7 11.9 12.3 c2 14.8 12.9 13.2 12.1 12.9 11.2 12.8 0.15 0.25 c3 14.0 11.9 12.5 13.6 12.4 12.6 11.8 9 c1 0.52 0.99 0.55 0.90 0.56 0.63 0.74 c2 0.56 1.36 0.50 1.07 0.46 0.45 0.72 0.05 0.10 c3 0.52 0.87 0.57 0.85 0.60 0.70 0.75 10 c1 4.45 3.44 3.88 3.64 3.57 3.32 3.65 c2 4.17 3.27 3.72 3.79 4.17 3.78 3.57 0.25 0.71 c3 4.13 3.01 3.40 3.35 3.47 3.11 3.31 11 c1 13.2 15.3 12.7 14.7 109 9.5 10.4 c2 12.9 11.3 14.4 10.9 109 11.3 13.2 0.33 0.23 c3 12.5 12.6 14.4 15.0 11.9 12.8 14.7 12 c1 137 128 102 106 96 92 102 c2 110 92 92 101 100 82 100 6.2 7.8 c3 101 92 88 113 97 95 111 The studied character: 1-12 the same meanings as in table 1; The significance of A,C factors graduations is presented in text at the chapter `Material and methods`; 5% LSD: 1- A constant factor, C variable factor; 2-C constant factor; A variable factor. 120

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