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Relationship between light, fruit and leaf mineral content with albinism incidence in strawberry (Fragaria x ananassa Duch.)
Scientia Horticulturae 109 (2006) 66–70 www.elsevier.com/locate/scihorti
Relationship between light, fruit and leaf mineral content with albinism incidence in strawberry (Fragaria x ananassa Duch.) R.R. Sharma *, V.B. Patel, Hare Krishna Division of Fruits and Horticultural Technology, Indian Agricultural Research Institute, New Delhi-110012, India Received 31 August 2004; received in revised form 25 November 2005; accepted 15 March 2006
Abstract A study was conducted in strawberry to establish a relationship between shading, mineral nutrient of leaves and fruits with albinism incidence. Plants grown under shade produced albino fruits in higher proportion than those grown in open fields. Similarly, plants under shade produced smaller sized fruits and have lower fruit yield. Among cultivars, Etna had highest incidence of albinism (49.6%) and Sweet Charlie the lowest (14.4%). Dry matter content (%), concentration of five major nutrients, viz. N, P, K, Ca, Mg, S and N:Ca and K:Ca nutrient ratios did not differ significantly in the leaves of plants producing normal or albino fruits. However, in contrast, the concentration of K was notably higher (1.97 mg g 1 fresh tissue weight) and that of Ca was lower (0.098 mg g 1 fresh tissue weight) in albino fruits than normal ones. Consequently, the ratios of N:Ca (11.34) and K:Ca (20.08) were higher in albino fruits than normal ones. Cultivars also differed widely in respect to dry matter (%), mineral content and nutrient ratios. Thus, it appears that lower light intensity favours the development of albinism in strawberry, and it seems that calcium is not the basic cause of albinism, but increased vigour associated with overuse of N and K might be positively associated with it. # 2006 Elsevier B.V. All rights reserved. Keywords: Albinism; Fragaria x ananassa; Nutrient element; Nutrient ratio; Shading
1. Introduction Strawberry is one of the most delicious and refreshing fruits of the world. In India, efforts made to boost its cultivation during early 1960s got a set back because of poor adaptation of the introduced varieties and lack of knowledge on technical know-how about its cultivation (Sharma, 2002; Sharma and Sharma, 2004). However, later many day-neutral (DN) varieties were introduced from different countries and agro-techniques were standardized, which has boosted strawberry cultivation in India, though major commercial sites are located in sub-tropical zone only (Sharma et al., 2003). In this zone, many varieties are grown, but Chandler, Douglas, Etna and Fern have been found most suitable for commercial cultivation. However, Sharma and Sharma (2003a) have very recently reported that Sweet Charlie is the best cultivar for this zone. In India, strawberry is mainly
* Corresponding author. Present address: CIPHET, Abohar-152116, Punjab, India. Tel.: +91 1634 225313 (O); + 91 1634 221384 (R); fax: +91 1634 225313. E-mail addresses: [email protected], [email protected] (R.R. Sharma). 0304-4238/$ – see front matter # 2006 Elsevier B.V. All rights reserved. doi:10.1016/j.scienta.2006.03.009
grown in open fields, and rarely under green house or other protected structures. Strawberry suffers from various physiological disorders, but albinism causes greater loss, in which, insufficiently coloured, and sometimes white fruits are produced. Such fruits develop almost normally but look swollen, have mottled pink peel with pale spots and show waxy appearance (Ulrich, 1971; Sharma, 2002; Sharma et al., 2003). Pulp of such fruits is usually white, poor flavoured and bitter acidic in taste. Because of lack of firmness, such fruits are highly susceptible to fruit-rot during storage and fetch lower prices in the markets (Sharma, 2002; Sharma and Sharma, 2004). Albinism in strawberries is probably caused by certain climatic conditions and extremes in nutrition (Ulrich, 1971; Sharma, 2002; Sharma and Sharma, 2004). Albino fruits usually appear in plants showing excessive vegetative growth, perhaps due to heavy N fertilization, suggesting that over nutrition might also be the cause of albinism (Sharma and Sharma, 2003b). Similarly, light intensity may have some relationship with albinism disorder (Ulrich, 1971). Lieten and Marcelle (1993a,b) have recorded higher ratios of K:Ca and N:Ca in albino fruits of ‘Elsanta’ strawberry, grown under protected structures. Hence, systematic studies were conducted
R.R. Sharma et al. / Scientia Horticulturae 109 (2006) 66–70
in commercially grown strawberry varieties under shade and open field conditions in sub-tropical climate, to determine the relationship, if exists, between light (shade), leaf and fruit mineral content with albinism disorder. 2. Materials and methods The studies were conducted in the Division of Fruits and Horticultural Technology, IARI, during 2001–2003. Two hundred runners, each of Chandler, Douglas, Etna, Fern and Sweet Charlie cultivars were procured from IARI, Regional Research Station, Shimla (HP) and were planted during mid-October on raised beds (10 m 1 m) in open and under partially shaded fields at a distance of 25 cm 20 cm (200 plants/bed), and were uniformly mulched with paddy straw. Partial shade was naturally provided to strawberry plants by the dense canopy of jujube (Zizyphus jujube) trees as the runners were planted between the interspaces of the tree rows. The average normal light intensity during the entire period of experimentation (mid-October to last March) was 720 mmol m 1 s 1, whereas under shade, it was much lower 336 mmol m 1 s 1. Further, the photosynthetic activity of strawberry plants under shade was lower (7.6 mmol m 1 s 1) than those grown in open field (12.4 720 mmol m 1 s 1). Because there was no significant variation in photosynthetic activity among different varieties, data have not been shown in a separate table. The albinism incidence was calculated by counting the normal and healthy fruits of shaded and open field grown, randomly selected 10 plants/bed, replicated five times. The albinism incidence was represented as percentage. Observations on average berry weight (g), fruit yield/plant (g) and length of harvesting period (days) were also recorded. For this, fruits of first seven pickings were taken in to account, as the fruits of later pickings were extremely smaller and have least consumer acceptability. For berry weight and yield, all fruits harvested in individual picking were taken into account. For determining length of harvesting period (days), the difference between first picking and last picking was recorded.
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Standard procedures were adopted for determining the mineral nutrient content in leaves and fruits (Marcelle, 1984). Nitrogen was measured by colorimetrically after a Kjeldahl digestion. Samples of albino and normal fruits were taken from randomly selected 10 plants/bed, with each sample containing about 500 g (fresh weight) (Lieten and Marcelle, 1993a; Shear and Faust, 1980). From each fruit, 3–4 mm thick longitudinal slices were taken, reducing the total weight of the sample to 120–130 g. Samples of the leaves were also taken on the same day and way as the fruit. Each leaf sample consisted of 30 median leaflets (Marcelle, 1984; Shear and Faust, 1980). The data generated from the experiment were pooled and analyzed, following factorial RBD (Panse and Sukhatme, 1984). 3. Results 3.1. Effect of shade on albinism incidence, berry weight, fruit yield and length of harvesting period Nearly 31% fruits of strawberry were affected by albinism. Shaded plants produced higher percentage (37.6%) of albino fruits than plants in open (25.2%) (Table 1). A greater variability in respect to albinism incidence was observed among different cultivars as Etna produced highest percentage of albino fruits (49.6%) and Sweet Charlie, the lowest (14.4%). Further, plants under shade produced significantly smaller fruits (11.8 g) and have lower fruit yield (172.6 g/plant) than those grown in open fields. The length of harvesting period was significantly higher (42.1 days) in plants under shade than plants under open fields (Table 1). Similarly, the interaction, shade cultivar for albinism incidence, average berry weight, fruit yield and length of harvesting period was also significant. 3.2. Dry matter (%), mineral nutrient content and nutrient ratios of normal and albino fruit Albino fruits have significantly lower dry matter content (5.24%) than normal fruits (7.29%). Though, there was no significant difference in the concentrations of nitrogen,
Table 1 Effect of shade on production of albino fruits, berry weight, fruit yield and length of harvesting period in strawberry Cultivar
Production of albino fruits (%)
Average berry weight (g)
Fruit yield (g/plant)
Shaded field
Open field
Mean
Shaded field
Open field
Mean
Shaded field
Open field
Mean
Shaded field
Open field
Mean
Chandler Douglas Etna Fern Sweet Charlie
48.6 36.3 56.2 28.5 18.3
32.5 25.1 42.9 15.2 10.5
40.6 30.7 49.6 21.9 14.4
13.2 9.3 9.6 10.3 11.7
15.6 11.3 10.8 12.2 13.2
14.4 10.3 10.2 11.3 12.5
172.3 159.3 156.2 166.6 208.5
198.2 169.5 166.3 179.5 225.5
185.3 164.4 161.3 173.1 217.0
42.5 39.3 40.2 42.8 45.6
36.2 32.3 35.4 35.2 37.8
39.4 35.8 37.8 39.0 41.7
Mean
37.6
25.2
31.4
11.8
12.6
172.6
187.8
42.1
35.4
CD (0.05)
Shade = 2.9; cultivar = 3.2; shade cultivar = 4.6
Shade = 0.32; cultivar = 0.45; shade cultivar = 1.2
Length of harvesting period (days)
Shade = 3.7; cultivar = 3.9; shade cultivar = 4.11
Shade = 1.4; cultivar = 1.6; shade cultivar = 1.7
Fruit type = 0.18; cultivar = 0.22; fruit cultivar = 0.33
Fruit type = 0.13; cultivar = 0.16; fruit cultivar = 0.33
phosphorus, magnesium and sulphur in albino and normal fruits, but the concentration of potassium was significantly higher (1.97 mg g 1 fresh tissue weight) and that of calcium was lower (0.098 mg g 1 fresh tissue weight) in albino fruits than in normal ones (1.72 and 0.128 mg g 1 fresh tissue weight, respectively) (Table 2). Consequently, the N:Ca (11.34) and K:Ca (20.08) ratios for albino fruits were much higher than normal fruits (7.97 and 13.47, respectively) (Table 3). Further, dry matter (%), concentrations of five major mineral nutrients and mineral nutrient ratios were also significantly influenced by cultivars and the interaction between shade and cultivar. 3.3. Dry matter (%), mineral nutrient content and nutrient ratios of the leaves of plants bearing normal and albino fruits
Fruit type = 0.13; cultivar = 0.06; fruit cultivar = 0.19
There was no significant difference either in dry matter content (%) or mineral content of the leaves of plants bearing normal and albino fruits (Table 4). Consequently, the N:Ca and K:Ca nutrient ratios were also non-significant. However, significant differences existed among cultivars for dry matter (%), mineral content and nutrient ratios (Tables 4 and 5).
Fruit type = 0.11; cultivar = 0.08; fruit cultivar = 0.13
4. Discussion
Fruit type = 0.18; cultivar = 0.27; fruit cultivar = 0.30
4.1. Effect of shade on albinism incidence, berry weight, fruit yield and length of harvesting period
AF, albino fruits; NF, normal fruits.
Fruit type = 0.08; cultivar = 0.03; fruit cultivar = 0.11 CD (0.05)
Fruit type = 0.013 cultivar = 0.11; fruit cultivar = 0.16
– 0.108 – 0.098 5.24
– 7.29 Mean
1.01
1.11
–
0.196
0.207
–
1.72
1.97
–
0.128
–
0.143
0.129
0.118
0.118 0.110 0.109 0.081 0.123
AF NF Mean
0.139 0.142 0.127 0.133 0.148
AF
0.130 0.128 0.120 0.128 0.140
NF
0.148 0.142 0.133 0.138 0.156
Mean
0.118 0.111 0.104 0.108 0.125
AF
0.103 0.097 0.089 0.092 0.110
NF
0.132 0.125 0.119 0.123 0.140 1.89 1.83 1.71 1.80 2.00
Mean AF
2.03 1.96 1.83 1.90 2.12 1.75 1.70 1.58 1.70 1.88
NF Mean
0.207 0.202 0.190 0.199 0.211 0.212 0.206 0.198 0.205 0.216
AF NF
0.201 0.198 0.182 0.193 0.206 1.13 1.08 0.98 1.03 1.11
Mean AF
1.18 1.12 1.03 1.08 1.14 1.08 1.03 0.93 0.98 1.07
NF Mean
6.41 6.14 6.28 6.17 6.33 5.32 5.18 5.23 5.17 5.28
AF NF
7.49 7.10 7.33 7.16 7.38 Chandler Douglas Etna Fern Sweet Charlie
Sulphur Magnesium Calcium Potassium Phosphorus Nitrogen
Mineral content (mg/g fresh tissue weight) Dry matter (%) Cultivar
Table 2 Dry matter (%) and major mineral content of albino and normal fruits in different strawberry cultivars
0.130 0.118 0.113 0.095 0.136
Mean
R.R. Sharma et al. / Scientia Horticulturae 109 (2006) 66–70 0.120 0.114 0.111 0.088 0.131
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Nearly 31% strawberry fruits were affected by albinism, a serious disorder, which was first described by Ulrich (1971) in green house grown strawberry, and later by Sharma and Sharma (2003a) in open field grown strawberries. Plants grown under shade produced higher percentage of albino fruits (37.6%) than those grown in open field (25.2%), which supports the contention that low light intensity favours the development of albinism in strawberry. Lieten and Marcelle (1993a) have also demonstrated that strawberry plants grown under low light intensities (shade) tend to produce albino fruits in higher proportion. Further, cultivars differed greatly in terms of producing albino fruits as Etna produced maximum percentage of albino fruits and Sweet Charlie the minimum, which may be attributed to genetic variability existing among the cultivars, as reported by Sharma et al. (2003) and Sharma and Sharma (2003a,b). Production of smaller fruits and lower yields by plants under shade than those grown in open fields may probably be due poor light interception, which rendered low photosynthetic activity in the shaded plants. Basically, for food manufacturing in plants, interception and utilization of sunlight is considered as most important, which determines the photosynthetic activity and ultimate limit of productivity (Salisbury and Ross, 1986). Strawberry is basically a light loving plants, and hence, light is considered as the major environmental factor for adequate growth, fruit-set and increased yield (Sharma and Sharma, 2004) and constant shading affects plant growth, fruit yield and runner production adversely (Ferree and Stang, 1988; Garrison
R.R. Sharma et al. / Scientia Horticulturae 109 (2006) 66–70
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Table 3 Mineral nutrient ratios of normal and albino fruits of different strawberry cultivars Cultivar
Mineral nutrient ratio N:Ca ratio
K:Ca ratio
Normal fruits
Albino fruits
Mean
Normal fruits
Albino fruits
Mean
Chandler Douglas Etna Fern Sweet Charlie
8.18 8.24 7.81 7.98 7.64
11.46 11.56 11.57 11.77 10.36
9.82 9.90 9.69 9.88 9.00
13.23 13.60 13.28 13.82 13.43
19.71 20.21 20.65 20.65 19.27
16.47 16.91 16.92 17.24 16.35
Mean
7.97
11.34
13.47
20.08
CD (0.05)
Fruit type = 1.32; cultivar = 0.10; fruit cultivar = 3.33
Fruit type = 1.44; cultivar = 0.30; fruit cultivar = 1.96
Table 4 Dry matter (%) and major mineral content of the leaves of plants bearing albino and normal fruits in different strawberry cultivars Cultivar
Dry matter (%)
Mineral content (% DM) Nitrogen
Phosphorus
Potassium
Calcium
Magnesium
Sulphur
NF
AF
Mean NF
AF
Mean NF
AF
Mean NF
AF
Mean NF
AF
Mean NF
AF
Mean NF
AF
Mean
Chandler Douglas Etna Fern Sweet Charlie
30.2 25.2 19.2 23.2 27.5
29.8 24.7 18.6 22.6 26.9
30.0 25.0 18.9 22.9 27.2
3.46 3.32 3.22 3.26 3.38
3.52 3.36 3.28 3.32 3.44
0.356 0.333 0.316 0.325 0.342
0.343 0.324 0.304 0.319 0.334
2.88 2.68 2.49 2.56 2.72
2.73 2.55 2.40 2.49 2.61
1.42 1.37 1.28 1.33 1.38
1.40 1.36 1.28 1.32 1.37
0.550 0.543 0.533 0.539 0.548
0.552 0.544 0.532 0.541 0.547
0.098 0.085 0.072 0.072 0.103
0.096 0.088 0.073 0.073 0.105
Mean
25.1 24.5 –
3.44 3.33 –
0.315 0.334 –
2.44 2.67 –
1.33 1.36 –
0.543 0.543 –
0.090 0.083 –
CD (0.05)
Fruit type = 0.81; cultivar = 1.42; fruit cultivar = 2.21
Fruit type = 0.82; cultivar = 0.08; fruit cultivar = 0.41
Fruit type = 0.41; cultivar = 0.12; fruit cultivar = 0.86
Fruit type = 0.33; cultivar = 0.03; fruit cultivar = 0.77
Fruit type = 0.25; cultivar = 0.03; fruit cultivar = 0.86
Fruit type = 0.08; cultivar = 0.03; fruit cultivar = 0.11
Fruit type = 0.12; cultivar = 0.03; fruit cultivar = 0.89
3.58 3.40 3.33 3.38 3.49
0.330 0.315 0.292 0.312 0.325
2.57 2.42 2.30 2.42 2.49
1.38 1.35 1.27 1.30 1.35
0.553 0.545 0.531 0.542 0.546
0.100 0.090 0.075 0.075 0.109
AF, albino fruit; NF, normal fruit.
et al., 1991). Production of lower yield by the shaded plants may also be due to production of albino fruits in higher percentage than normal fruits (Table 1). Similarly, the period of fruit harvesting was lengthened in shaded plants, probably because plants under shade took more time to mature or ripen their fruits than those under full light (open fields) as constant shading has been reported to delay the fruiting period in strawberry (Ferree and Stang, 1988).
4.2. Dry matter (%), mineral content and nutrient ratios in leaves and fruits Leaves are largely known as indicative of the nutrient deficiencies. However, there were no significant differences in the dry matter (%), mineral nutrient content and nutrient ratios of the leaves of plants producing normal and albino fruits, although cultivars differed widely in this respect. In contrast,
Table 5 Mineral nutrient ratios of leaves bearing normal and albino fruits in different strawberry cultivars Cultivar
Mineral nutrient ratio N:Ca ratio
K:Ca ratio
Normal fruits
Albino fruits
Mean
Normal fruits
Albino fruits
Mean
Chandler Douglas Etna Fern Sweet Charlie
2.59 2.52 2.62 2.60 2.56
2.44 2.42 2.52 2.45 2.45
2.52 2.47 2.57 2.53 2.51
1.86 1.79 1.81 1.86 1.84
2.03 1.96 1.95 1.92 1.97
1.95 1.88 1.88 1.89 1.91
Mean
2.58
2.46
1.83
1.97
–
CD (0.05)
Fruit type = 0.32; cultivar = 0.18; fruit cultivar = 1.22
Fruit type = 0.33; cultivar = 0.17; fruit cultivar = 1.28
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dry matter contents of albino fruits were lower than normal fruits. Further, among five major nutrients, potassium was higher and calcium was notably lower in albino fruits than normal fruits, indicating higher ratios for N:Ca and K:Ca, respectively. Higher nutrient ratios in albino fruits suggest that such fruits are physiologically riper and more senescent than normal fruits, though they have poor colour development (Marcelle, 1984; Sharma and Sharma, 2003a,b; Sharma et al., 2006). Similarly, this also supports that calcium deficiency is not basically responsible for albinism in strawberry, which has also been reported by Lieten and Marcelle (1993a,b). Further, lower dry matter content in albino fruits than normal fruits indicated that albino fruits were more hydrated, which may be due to increased competition between leaves and fruits for different nutrients during the period of excessive vegetative growth (Lieten and Marcelle, 1993a). Increased vigour is usually associated with overuse of N and K, as a result, vigorous cultivar (e.g., Etna) has produced higher percentage of albino fruits than semi-vigorous or dwarf cultivars (e.g., Sweet Charlie) (Sharma and Sharma, 2003a). Although, there is no report in the literature to support that deficiency of a particular nutrient affects colour development in strawberry, but it is known that excessive use of N in fruit plants affects fruit maturity, quality, increases the susceptibility to physiological disorders (e.g., bitter pit in apples) and hinders colour development in some deciduous fruits (Shear and Faust, 1980), and hence, higher N and K might have positive relationship with albinism. Significant differences in dry matter (%), mineral nutrient content and nutrient ratios in different cultivars may be attributed to genetic variability existing among cultivars (Sharma and Sharma, 2003a,b; Sharma et al., 2006). Thus, it appears from the study that lower light intensity favours the development of albinism incidence in strawberry. Although, it seems that calcium is not the basic cause of
albinism, but increased vigour associated with overuse of N and K might be positively associated with it. References Ferree, D.C., Stang, E.J., 1988. Seasonal plant shading, growth and fruting in Earliglow strawberry. J. Am. Soc. Hort. Sci. 113, 322–324. Garrison, S.E., Williams, J.M., Barden, J.A., Kushad, M.M., 1991. Shade decreases fruit yield in strawberry. Adv. Strawberry Prod. 10, 53–55. Lieten, F., Marcelle, R.D., 1993a. Relationships between fruit mineral content and the ‘albinism’ disorder in strawberry. Ann. Appl. Biol. 123, 433–439. Lieten, F., Marcelle, R.D., 1993b. Relationships between fruit mineral content and the albinism disorder in ‘Elsanta’ strawberry plants. Acta Hort. 348, 294–298. Marcelle, R.D., 1984. Mineral analysis and storage properties of fruit. In: Martin-Prevel, P. (Ed.), VIth International Colloquium for the Optimization of Plant Nutrition, vol. 2. AIONP/GERDAT, Montppellier, pp. 365–371. Panse, V.G., Sukhatme, P.V., 1984. Statistical Methods for Agricultural Workers, third ed. ICAR, New Delhi, India. Salisbury, F.B., Ross, C.W., 1986. Plant Physiology. Wadsworth Publishing Co. Inc., Belmont, CA. Sharma, R.R., 2002. Growing Strawberries. Intl. Book Distributing Co., Lucknow, UP, India. Sharma, R.R., Krishna, H., Patel, V.B., Dahuja, A., Singh, R., 2006. Fruit calcium content and lipoxygenase activity in relation to albinism disorder in strawberry. Scientia Hort. 107, 150–154. Sharma, R.R., Sharma, V.P., 2003a. Mulch type influences plant growth, albinism disorder and fruit quality in strawberry (Fragaria x ananassa Dusch.). Fruits 58, 221–227. Sharma, R.R., Sharma, V.P., 2003b. Plant growth and albinism disorder in different strawberry cultivars under Delhi conditions. Ind. J. Hort. 61, 92–93. Sharma, R.R., Sharma, V.P., Pandey, S.N., Srivastav, M., 2003. Effect of mulching on plant growth, leaf physiology and albinism disorder in strawberry. Ind. J. Plant Physiol. 8, 462–466. Sharma, V.P., Sharma, R.R., 2004. The Strawberry. ICAR, New Delhi, India. Shear, C.B., Faust, M., 1980. Nutritional ranges in decidous tree fruits and nuts. In: Janick, J. (Ed.), Horticulture Review, vol. 2. AVI Publishing Co. Inc., Wesport, pp. 142–163. Ulrich, A., 1971. Albino strawberry fruit study. In: Progress Report in Strawberry News Bulletin, vol. 16, Strawberry Advisory Board, CA, pp. 1–3.
Relationship between light, fruit and leaf mineral content with albinism incidence in strawberry (Fragaria x ananassa Duch.) R.R. Sharma *, V.B. Patel, Hare Krishna Division of Fruits and Horticultural Technology, Indian Agricultural Research Institute, New Delhi-110012, India Received 31 August 2004; received in revised form 25 November 2005; accepted 15 March 2006
Abstract A study was conducted in strawberry to establish a relationship between shading, mineral nutrient of leaves and fruits with albinism incidence. Plants grown under shade produced albino fruits in higher proportion than those grown in open fields. Similarly, plants under shade produced smaller sized fruits and have lower fruit yield. Among cultivars, Etna had highest incidence of albinism (49.6%) and Sweet Charlie the lowest (14.4%). Dry matter content (%), concentration of five major nutrients, viz. N, P, K, Ca, Mg, S and N:Ca and K:Ca nutrient ratios did not differ significantly in the leaves of plants producing normal or albino fruits. However, in contrast, the concentration of K was notably higher (1.97 mg g 1 fresh tissue weight) and that of Ca was lower (0.098 mg g 1 fresh tissue weight) in albino fruits than normal ones. Consequently, the ratios of N:Ca (11.34) and K:Ca (20.08) were higher in albino fruits than normal ones. Cultivars also differed widely in respect to dry matter (%), mineral content and nutrient ratios. Thus, it appears that lower light intensity favours the development of albinism in strawberry, and it seems that calcium is not the basic cause of albinism, but increased vigour associated with overuse of N and K might be positively associated with it. # 2006 Elsevier B.V. All rights reserved. Keywords: Albinism; Fragaria x ananassa; Nutrient element; Nutrient ratio; Shading
1. Introduction Strawberry is one of the most delicious and refreshing fruits of the world. In India, efforts made to boost its cultivation during early 1960s got a set back because of poor adaptation of the introduced varieties and lack of knowledge on technical know-how about its cultivation (Sharma, 2002; Sharma and Sharma, 2004). However, later many day-neutral (DN) varieties were introduced from different countries and agro-techniques were standardized, which has boosted strawberry cultivation in India, though major commercial sites are located in sub-tropical zone only (Sharma et al., 2003). In this zone, many varieties are grown, but Chandler, Douglas, Etna and Fern have been found most suitable for commercial cultivation. However, Sharma and Sharma (2003a) have very recently reported that Sweet Charlie is the best cultivar for this zone. In India, strawberry is mainly
* Corresponding author. Present address: CIPHET, Abohar-152116, Punjab, India. Tel.: +91 1634 225313 (O); + 91 1634 221384 (R); fax: +91 1634 225313. E-mail addresses: [email protected], [email protected] (R.R. Sharma). 0304-4238/$ – see front matter # 2006 Elsevier B.V. All rights reserved. doi:10.1016/j.scienta.2006.03.009
grown in open fields, and rarely under green house or other protected structures. Strawberry suffers from various physiological disorders, but albinism causes greater loss, in which, insufficiently coloured, and sometimes white fruits are produced. Such fruits develop almost normally but look swollen, have mottled pink peel with pale spots and show waxy appearance (Ulrich, 1971; Sharma, 2002; Sharma et al., 2003). Pulp of such fruits is usually white, poor flavoured and bitter acidic in taste. Because of lack of firmness, such fruits are highly susceptible to fruit-rot during storage and fetch lower prices in the markets (Sharma, 2002; Sharma and Sharma, 2004). Albinism in strawberries is probably caused by certain climatic conditions and extremes in nutrition (Ulrich, 1971; Sharma, 2002; Sharma and Sharma, 2004). Albino fruits usually appear in plants showing excessive vegetative growth, perhaps due to heavy N fertilization, suggesting that over nutrition might also be the cause of albinism (Sharma and Sharma, 2003b). Similarly, light intensity may have some relationship with albinism disorder (Ulrich, 1971). Lieten and Marcelle (1993a,b) have recorded higher ratios of K:Ca and N:Ca in albino fruits of ‘Elsanta’ strawberry, grown under protected structures. Hence, systematic studies were conducted
R.R. Sharma et al. / Scientia Horticulturae 109 (2006) 66–70
in commercially grown strawberry varieties under shade and open field conditions in sub-tropical climate, to determine the relationship, if exists, between light (shade), leaf and fruit mineral content with albinism disorder. 2. Materials and methods The studies were conducted in the Division of Fruits and Horticultural Technology, IARI, during 2001–2003. Two hundred runners, each of Chandler, Douglas, Etna, Fern and Sweet Charlie cultivars were procured from IARI, Regional Research Station, Shimla (HP) and were planted during mid-October on raised beds (10 m 1 m) in open and under partially shaded fields at a distance of 25 cm 20 cm (200 plants/bed), and were uniformly mulched with paddy straw. Partial shade was naturally provided to strawberry plants by the dense canopy of jujube (Zizyphus jujube) trees as the runners were planted between the interspaces of the tree rows. The average normal light intensity during the entire period of experimentation (mid-October to last March) was 720 mmol m 1 s 1, whereas under shade, it was much lower 336 mmol m 1 s 1. Further, the photosynthetic activity of strawberry plants under shade was lower (7.6 mmol m 1 s 1) than those grown in open field (12.4 720 mmol m 1 s 1). Because there was no significant variation in photosynthetic activity among different varieties, data have not been shown in a separate table. The albinism incidence was calculated by counting the normal and healthy fruits of shaded and open field grown, randomly selected 10 plants/bed, replicated five times. The albinism incidence was represented as percentage. Observations on average berry weight (g), fruit yield/plant (g) and length of harvesting period (days) were also recorded. For this, fruits of first seven pickings were taken in to account, as the fruits of later pickings were extremely smaller and have least consumer acceptability. For berry weight and yield, all fruits harvested in individual picking were taken into account. For determining length of harvesting period (days), the difference between first picking and last picking was recorded.
67
Standard procedures were adopted for determining the mineral nutrient content in leaves and fruits (Marcelle, 1984). Nitrogen was measured by colorimetrically after a Kjeldahl digestion. Samples of albino and normal fruits were taken from randomly selected 10 plants/bed, with each sample containing about 500 g (fresh weight) (Lieten and Marcelle, 1993a; Shear and Faust, 1980). From each fruit, 3–4 mm thick longitudinal slices were taken, reducing the total weight of the sample to 120–130 g. Samples of the leaves were also taken on the same day and way as the fruit. Each leaf sample consisted of 30 median leaflets (Marcelle, 1984; Shear and Faust, 1980). The data generated from the experiment were pooled and analyzed, following factorial RBD (Panse and Sukhatme, 1984). 3. Results 3.1. Effect of shade on albinism incidence, berry weight, fruit yield and length of harvesting period Nearly 31% fruits of strawberry were affected by albinism. Shaded plants produced higher percentage (37.6%) of albino fruits than plants in open (25.2%) (Table 1). A greater variability in respect to albinism incidence was observed among different cultivars as Etna produced highest percentage of albino fruits (49.6%) and Sweet Charlie, the lowest (14.4%). Further, plants under shade produced significantly smaller fruits (11.8 g) and have lower fruit yield (172.6 g/plant) than those grown in open fields. The length of harvesting period was significantly higher (42.1 days) in plants under shade than plants under open fields (Table 1). Similarly, the interaction, shade cultivar for albinism incidence, average berry weight, fruit yield and length of harvesting period was also significant. 3.2. Dry matter (%), mineral nutrient content and nutrient ratios of normal and albino fruit Albino fruits have significantly lower dry matter content (5.24%) than normal fruits (7.29%). Though, there was no significant difference in the concentrations of nitrogen,
Table 1 Effect of shade on production of albino fruits, berry weight, fruit yield and length of harvesting period in strawberry Cultivar
Production of albino fruits (%)
Average berry weight (g)
Fruit yield (g/plant)
Shaded field
Open field
Mean
Shaded field
Open field
Mean
Shaded field
Open field
Mean
Shaded field
Open field
Mean
Chandler Douglas Etna Fern Sweet Charlie
48.6 36.3 56.2 28.5 18.3
32.5 25.1 42.9 15.2 10.5
40.6 30.7 49.6 21.9 14.4
13.2 9.3 9.6 10.3 11.7
15.6 11.3 10.8 12.2 13.2
14.4 10.3 10.2 11.3 12.5
172.3 159.3 156.2 166.6 208.5
198.2 169.5 166.3 179.5 225.5
185.3 164.4 161.3 173.1 217.0
42.5 39.3 40.2 42.8 45.6
36.2 32.3 35.4 35.2 37.8
39.4 35.8 37.8 39.0 41.7
Mean
37.6
25.2
31.4
11.8
12.6
172.6
187.8
42.1
35.4
CD (0.05)
Shade = 2.9; cultivar = 3.2; shade cultivar = 4.6
Shade = 0.32; cultivar = 0.45; shade cultivar = 1.2
Length of harvesting period (days)
Shade = 3.7; cultivar = 3.9; shade cultivar = 4.11
Shade = 1.4; cultivar = 1.6; shade cultivar = 1.7
Fruit type = 0.18; cultivar = 0.22; fruit cultivar = 0.33
Fruit type = 0.13; cultivar = 0.16; fruit cultivar = 0.33
phosphorus, magnesium and sulphur in albino and normal fruits, but the concentration of potassium was significantly higher (1.97 mg g 1 fresh tissue weight) and that of calcium was lower (0.098 mg g 1 fresh tissue weight) in albino fruits than in normal ones (1.72 and 0.128 mg g 1 fresh tissue weight, respectively) (Table 2). Consequently, the N:Ca (11.34) and K:Ca (20.08) ratios for albino fruits were much higher than normal fruits (7.97 and 13.47, respectively) (Table 3). Further, dry matter (%), concentrations of five major mineral nutrients and mineral nutrient ratios were also significantly influenced by cultivars and the interaction between shade and cultivar. 3.3. Dry matter (%), mineral nutrient content and nutrient ratios of the leaves of plants bearing normal and albino fruits
Fruit type = 0.13; cultivar = 0.06; fruit cultivar = 0.19
There was no significant difference either in dry matter content (%) or mineral content of the leaves of plants bearing normal and albino fruits (Table 4). Consequently, the N:Ca and K:Ca nutrient ratios were also non-significant. However, significant differences existed among cultivars for dry matter (%), mineral content and nutrient ratios (Tables 4 and 5).
Fruit type = 0.11; cultivar = 0.08; fruit cultivar = 0.13
4. Discussion
Fruit type = 0.18; cultivar = 0.27; fruit cultivar = 0.30
4.1. Effect of shade on albinism incidence, berry weight, fruit yield and length of harvesting period
AF, albino fruits; NF, normal fruits.
Fruit type = 0.08; cultivar = 0.03; fruit cultivar = 0.11 CD (0.05)
Fruit type = 0.013 cultivar = 0.11; fruit cultivar = 0.16
– 0.108 – 0.098 5.24
– 7.29 Mean
1.01
1.11
–
0.196
0.207
–
1.72
1.97
–
0.128
–
0.143
0.129
0.118
0.118 0.110 0.109 0.081 0.123
AF NF Mean
0.139 0.142 0.127 0.133 0.148
AF
0.130 0.128 0.120 0.128 0.140
NF
0.148 0.142 0.133 0.138 0.156
Mean
0.118 0.111 0.104 0.108 0.125
AF
0.103 0.097 0.089 0.092 0.110
NF
0.132 0.125 0.119 0.123 0.140 1.89 1.83 1.71 1.80 2.00
Mean AF
2.03 1.96 1.83 1.90 2.12 1.75 1.70 1.58 1.70 1.88
NF Mean
0.207 0.202 0.190 0.199 0.211 0.212 0.206 0.198 0.205 0.216
AF NF
0.201 0.198 0.182 0.193 0.206 1.13 1.08 0.98 1.03 1.11
Mean AF
1.18 1.12 1.03 1.08 1.14 1.08 1.03 0.93 0.98 1.07
NF Mean
6.41 6.14 6.28 6.17 6.33 5.32 5.18 5.23 5.17 5.28
AF NF
7.49 7.10 7.33 7.16 7.38 Chandler Douglas Etna Fern Sweet Charlie
Sulphur Magnesium Calcium Potassium Phosphorus Nitrogen
Mineral content (mg/g fresh tissue weight) Dry matter (%) Cultivar
Table 2 Dry matter (%) and major mineral content of albino and normal fruits in different strawberry cultivars
0.130 0.118 0.113 0.095 0.136
Mean
R.R. Sharma et al. / Scientia Horticulturae 109 (2006) 66–70 0.120 0.114 0.111 0.088 0.131
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Nearly 31% strawberry fruits were affected by albinism, a serious disorder, which was first described by Ulrich (1971) in green house grown strawberry, and later by Sharma and Sharma (2003a) in open field grown strawberries. Plants grown under shade produced higher percentage of albino fruits (37.6%) than those grown in open field (25.2%), which supports the contention that low light intensity favours the development of albinism in strawberry. Lieten and Marcelle (1993a) have also demonstrated that strawberry plants grown under low light intensities (shade) tend to produce albino fruits in higher proportion. Further, cultivars differed greatly in terms of producing albino fruits as Etna produced maximum percentage of albino fruits and Sweet Charlie the minimum, which may be attributed to genetic variability existing among the cultivars, as reported by Sharma et al. (2003) and Sharma and Sharma (2003a,b). Production of smaller fruits and lower yields by plants under shade than those grown in open fields may probably be due poor light interception, which rendered low photosynthetic activity in the shaded plants. Basically, for food manufacturing in plants, interception and utilization of sunlight is considered as most important, which determines the photosynthetic activity and ultimate limit of productivity (Salisbury and Ross, 1986). Strawberry is basically a light loving plants, and hence, light is considered as the major environmental factor for adequate growth, fruit-set and increased yield (Sharma and Sharma, 2004) and constant shading affects plant growth, fruit yield and runner production adversely (Ferree and Stang, 1988; Garrison
R.R. Sharma et al. / Scientia Horticulturae 109 (2006) 66–70
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Table 3 Mineral nutrient ratios of normal and albino fruits of different strawberry cultivars Cultivar
Mineral nutrient ratio N:Ca ratio
K:Ca ratio
Normal fruits
Albino fruits
Mean
Normal fruits
Albino fruits
Mean
Chandler Douglas Etna Fern Sweet Charlie
8.18 8.24 7.81 7.98 7.64
11.46 11.56 11.57 11.77 10.36
9.82 9.90 9.69 9.88 9.00
13.23 13.60 13.28 13.82 13.43
19.71 20.21 20.65 20.65 19.27
16.47 16.91 16.92 17.24 16.35
Mean
7.97
11.34
13.47
20.08
CD (0.05)
Fruit type = 1.32; cultivar = 0.10; fruit cultivar = 3.33
Fruit type = 1.44; cultivar = 0.30; fruit cultivar = 1.96
Table 4 Dry matter (%) and major mineral content of the leaves of plants bearing albino and normal fruits in different strawberry cultivars Cultivar
Dry matter (%)
Mineral content (% DM) Nitrogen
Phosphorus
Potassium
Calcium
Magnesium
Sulphur
NF
AF
Mean NF
AF
Mean NF
AF
Mean NF
AF
Mean NF
AF
Mean NF
AF
Mean NF
AF
Mean
Chandler Douglas Etna Fern Sweet Charlie
30.2 25.2 19.2 23.2 27.5
29.8 24.7 18.6 22.6 26.9
30.0 25.0 18.9 22.9 27.2
3.46 3.32 3.22 3.26 3.38
3.52 3.36 3.28 3.32 3.44
0.356 0.333 0.316 0.325 0.342
0.343 0.324 0.304 0.319 0.334
2.88 2.68 2.49 2.56 2.72
2.73 2.55 2.40 2.49 2.61
1.42 1.37 1.28 1.33 1.38
1.40 1.36 1.28 1.32 1.37
0.550 0.543 0.533 0.539 0.548
0.552 0.544 0.532 0.541 0.547
0.098 0.085 0.072 0.072 0.103
0.096 0.088 0.073 0.073 0.105
Mean
25.1 24.5 –
3.44 3.33 –
0.315 0.334 –
2.44 2.67 –
1.33 1.36 –
0.543 0.543 –
0.090 0.083 –
CD (0.05)
Fruit type = 0.81; cultivar = 1.42; fruit cultivar = 2.21
Fruit type = 0.82; cultivar = 0.08; fruit cultivar = 0.41
Fruit type = 0.41; cultivar = 0.12; fruit cultivar = 0.86
Fruit type = 0.33; cultivar = 0.03; fruit cultivar = 0.77
Fruit type = 0.25; cultivar = 0.03; fruit cultivar = 0.86
Fruit type = 0.08; cultivar = 0.03; fruit cultivar = 0.11
Fruit type = 0.12; cultivar = 0.03; fruit cultivar = 0.89
3.58 3.40 3.33 3.38 3.49
0.330 0.315 0.292 0.312 0.325
2.57 2.42 2.30 2.42 2.49
1.38 1.35 1.27 1.30 1.35
0.553 0.545 0.531 0.542 0.546
0.100 0.090 0.075 0.075 0.109
AF, albino fruit; NF, normal fruit.
et al., 1991). Production of lower yield by the shaded plants may also be due to production of albino fruits in higher percentage than normal fruits (Table 1). Similarly, the period of fruit harvesting was lengthened in shaded plants, probably because plants under shade took more time to mature or ripen their fruits than those under full light (open fields) as constant shading has been reported to delay the fruiting period in strawberry (Ferree and Stang, 1988).
4.2. Dry matter (%), mineral content and nutrient ratios in leaves and fruits Leaves are largely known as indicative of the nutrient deficiencies. However, there were no significant differences in the dry matter (%), mineral nutrient content and nutrient ratios of the leaves of plants producing normal and albino fruits, although cultivars differed widely in this respect. In contrast,
Table 5 Mineral nutrient ratios of leaves bearing normal and albino fruits in different strawberry cultivars Cultivar
Mineral nutrient ratio N:Ca ratio
K:Ca ratio
Normal fruits
Albino fruits
Mean
Normal fruits
Albino fruits
Mean
Chandler Douglas Etna Fern Sweet Charlie
2.59 2.52 2.62 2.60 2.56
2.44 2.42 2.52 2.45 2.45
2.52 2.47 2.57 2.53 2.51
1.86 1.79 1.81 1.86 1.84
2.03 1.96 1.95 1.92 1.97
1.95 1.88 1.88 1.89 1.91
Mean
2.58
2.46
1.83
1.97
–
CD (0.05)
Fruit type = 0.32; cultivar = 0.18; fruit cultivar = 1.22
Fruit type = 0.33; cultivar = 0.17; fruit cultivar = 1.28
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R.R. Sharma et al. / Scientia Horticulturae 109 (2006) 66–70
dry matter contents of albino fruits were lower than normal fruits. Further, among five major nutrients, potassium was higher and calcium was notably lower in albino fruits than normal fruits, indicating higher ratios for N:Ca and K:Ca, respectively. Higher nutrient ratios in albino fruits suggest that such fruits are physiologically riper and more senescent than normal fruits, though they have poor colour development (Marcelle, 1984; Sharma and Sharma, 2003a,b; Sharma et al., 2006). Similarly, this also supports that calcium deficiency is not basically responsible for albinism in strawberry, which has also been reported by Lieten and Marcelle (1993a,b). Further, lower dry matter content in albino fruits than normal fruits indicated that albino fruits were more hydrated, which may be due to increased competition between leaves and fruits for different nutrients during the period of excessive vegetative growth (Lieten and Marcelle, 1993a). Increased vigour is usually associated with overuse of N and K, as a result, vigorous cultivar (e.g., Etna) has produced higher percentage of albino fruits than semi-vigorous or dwarf cultivars (e.g., Sweet Charlie) (Sharma and Sharma, 2003a). Although, there is no report in the literature to support that deficiency of a particular nutrient affects colour development in strawberry, but it is known that excessive use of N in fruit plants affects fruit maturity, quality, increases the susceptibility to physiological disorders (e.g., bitter pit in apples) and hinders colour development in some deciduous fruits (Shear and Faust, 1980), and hence, higher N and K might have positive relationship with albinism. Significant differences in dry matter (%), mineral nutrient content and nutrient ratios in different cultivars may be attributed to genetic variability existing among cultivars (Sharma and Sharma, 2003a,b; Sharma et al., 2006). Thus, it appears from the study that lower light intensity favours the development of albinism incidence in strawberry. Although, it seems that calcium is not the basic cause of
albinism, but increased vigour associated with overuse of N and K might be positively associated with it. References Ferree, D.C., Stang, E.J., 1988. Seasonal plant shading, growth and fruting in Earliglow strawberry. J. Am. Soc. Hort. Sci. 113, 322–324. Garrison, S.E., Williams, J.M., Barden, J.A., Kushad, M.M., 1991. Shade decreases fruit yield in strawberry. Adv. Strawberry Prod. 10, 53–55. Lieten, F., Marcelle, R.D., 1993a. Relationships between fruit mineral content and the ‘albinism’ disorder in strawberry. Ann. Appl. Biol. 123, 433–439. Lieten, F., Marcelle, R.D., 1993b. Relationships between fruit mineral content and the albinism disorder in ‘Elsanta’ strawberry plants. Acta Hort. 348, 294–298. Marcelle, R.D., 1984. Mineral analysis and storage properties of fruit. In: Martin-Prevel, P. (Ed.), VIth International Colloquium for the Optimization of Plant Nutrition, vol. 2. AIONP/GERDAT, Montppellier, pp. 365–371. Panse, V.G., Sukhatme, P.V., 1984. Statistical Methods for Agricultural Workers, third ed. ICAR, New Delhi, India. Salisbury, F.B., Ross, C.W., 1986. Plant Physiology. Wadsworth Publishing Co. Inc., Belmont, CA. Sharma, R.R., 2002. Growing Strawberries. Intl. Book Distributing Co., Lucknow, UP, India. Sharma, R.R., Krishna, H., Patel, V.B., Dahuja, A., Singh, R., 2006. Fruit calcium content and lipoxygenase activity in relation to albinism disorder in strawberry. Scientia Hort. 107, 150–154. Sharma, R.R., Sharma, V.P., 2003a. Mulch type influences plant growth, albinism disorder and fruit quality in strawberry (Fragaria x ananassa Dusch.). Fruits 58, 221–227. Sharma, R.R., Sharma, V.P., 2003b. Plant growth and albinism disorder in different strawberry cultivars under Delhi conditions. Ind. J. Hort. 61, 92–93. Sharma, R.R., Sharma, V.P., Pandey, S.N., Srivastav, M., 2003. Effect of mulching on plant growth, leaf physiology and albinism disorder in strawberry. Ind. J. Plant Physiol. 8, 462–466. Sharma, V.P., Sharma, R.R., 2004. The Strawberry. ICAR, New Delhi, India. Shear, C.B., Faust, M., 1980. Nutritional ranges in decidous tree fruits and nuts. In: Janick, J. (Ed.), Horticulture Review, vol. 2. AVI Publishing Co. Inc., Wesport, pp. 142–163. Ulrich, A., 1971. Albino strawberry fruit study. In: Progress Report in Strawberry News Bulletin, vol. 16, Strawberry Advisory Board, CA, pp. 1–3.