Yield attributing characters as affected by Boron and Magnesium Harris

Yield attributing characters as affected by Boron and Magnesium
Harris, K. D.1*, Vanajah, T1., Abiramy, K1 and Puvanitha, S2.
1Department of Crop Science, Faculty of Agriculture, Eastern University, Chenkalady, Sri Lanka.
2Department of Agricultural Biology, Faculty of Agriculture, Eastern University, Chenkalady, Sri Lanka.
*[email protected]

Abstract
An experiment was conducted to determine the effects of graded Boron and Magnesium sulphate levels on the reproductive growth of chillies (Capsicum annuum L.) plants in the Crop Farm, Eastern University, Sri Lanka from August 2016 to October 2016. The experiment was arranged in a completely randomized design with four replications. Ten treatments were defined viz. control (T1), 50 ppm of B (T2), 100 ppm of B (T3), 150 ppm of B (T4), 50 ppm of Mg (T5), 100 ppm of Mg (T6), 150 ppm of Mg (T7), 50 ppm of B+Mg (T8), 100 ppm of B+Mg (T9) and 150 ppm of B+Mg (T10). H3BO3 and MgSO4.7H2O were used as boron and magnesium sources in this experiment respectively. They were applied at the time of flowering and two weeks after flowering. Agronomic practices were followed uniformly for all treatments. Results revealed that combined application of Magnesium and boron (T9- 100 ppm) had a significant effect on yield parameters namely number of seeds/ fruit, 100-seed weight, length of fruits, the diameter of fruits and dry weight of fruits/plant. However, sole application of boron @ 150 ppm increased the number of seeds/fruit and length of fruits. Application of Magnesium and boron @ 100 ppm increased the dry weight of green chilli by two-fold than that of control. Therefore, it is concluded that foliar application of Magnesium and boron @ 100 ppm resulted in the highest yield parameters of green chilli.

Key words: Boron, Magnesium,

Introduction
Chilli is originated in Mexico and the first domesticated crop in America. It is considered as cash, condiment and spice crop by Sri Lankans. Different varieties are grown for different purposes viz. vegetables, pickles, spices and condiments and available in different shapes and sizes i.e. mild and hot, namely bell peppers, jalapeños, and cayenne peppers.
In the 2016’s world production of chilli was cultivated in …. m. ha of land which gave the total production … m. ton. India is the major producer of chilli followed by China and Pakistan (Anon, 2014). In Sri Lanka, the total production of chilli is ….m. ton in an extent of …. m. ha (………, 2016), the major producing district being ……., ……, ……… In the Batticaloa district, chilli is grown in an extent of about 650 ha (Maha 2016 and Yala 2017) with the production of about 1307 ton of green chilli and 430 ton of dry chillies (Agriculture and Environment Statistics Division, 2017).
Chillies are rich in vitamins (A, B, C and E) and minerals (molybdenum, manganese, folate, potassium, thiamin, and copper) (Malini Rajoo, 2014). It has seven times greater vitamin C than that of orange and is good for slowing the calorie burning. They act as an antioxidant, detoxicant, painkiller, antibiotic and brain stimulator. Hence, it is a useful crop. The potential for production of chilli is high; however, farmers do not embark on its cultivation on a large scale because yields are low due to flower dropping and viral disease. Among the factors that determined yield are cultural practices and nutrients.
Chillies respond well to both boron and magnesium. Boron (B) is a key micronutrient for the growth of higher plants (Saleem et al., 2011). Deficiency leads to abnormal growth of reproductive organs (Huang et al., 2000) and reduction in yield (Nabi et al., 2006). Boron increases the fruit set percentage by promoting pollen germination and elongation of pollen tube (Abdalla, 2006). Boron is important for the synthesis and integrity of cell wall, cell wall lignification, metabolism of RNA, carbohydrate, phenol and Indole Acetic Acid (IAA), respiration and cell membrane integrity (Parr and Loughman, 1983).
Magnesium (Mg) has many significant functions in plants. It is a constituent of the chlorophyll and giving a green colour to the leaves. Magnesium deficiency greatly affects the crop growth. Hence, to enhance the production, foliar application of these nutrients is important.
To date, no systemic study has been carried out to test the effects of magnesium and boron on yield attributes of chilli and no evidence is available on the response to magnesium and boron. Hence, this investigation was undertaken to study the effects Mg and B nutrients on yield attributing characters to produce and supply green chilli for the local market.

Materials and Methods.
The experiment was conducted at the Crop Farm, Eastern University, Sri Lanka during the period September 2016 to November 2016 to study the yield attributing characters as affected by Boron and Magnesium Sulphate. Four weeks old seedlings were transplanted in poly bags with the mixture of red soil, sand and rotted cattle manure in the proportion of 1:1:1. The treatments were laid out in a Completely Randomized Design (CRD) with four replicates. Boron and Magnesium were applied as foliar sprays in the form of boric acid (H3BO3) and Magnesium Sulphate (MgSO4.7H2O). The treatments were; (T1) Control; (T2) B = 50 ppm; (T3) B = 100 ppm; (T4) B = 150 ppm; (T5) Mg= 50 ppm; (T6) Mg= 100 ppm; (T7) Mg = 150 ppm; (T8) B (50 ppm) + Mg (50 ppm); (T9) B (100 ppm) + Mg (100 ppm); (T10) B (150 ppm) + Mg (150 ppm). The first application was done at flower bud initiation stage and the second application was at 14 days after the first spray. All foliar applications were done early in morning for better absorption. All the agronomic practices were carried out as recommended by the Department of Agriculture, Sri Lanka. Data were statistically analysed using SAS 9.1 and means were separated using Duncan’s Multiple Range Test (DMRT) test at 5% significant level.

Results and Discussion
Number of seeds per fruit
The number of seeds per fruit was directly responding to the foliar applications of boron and magnesium (Table 1). The foliar application of magnesium sulphate and boric acid significantly increased the number of seeds per fruit was recorded in treatment T9 (B + Mg – 100 ppm, 73), T10 (B + Mg – 150 ppm, 70) followed by T8 (B + Mg – 50 ppm, 68), T6 (B– 100 ppm, 65), T7 (Mg – 150 ppm, 64) and T2 (B – 50 ppm, 60) (Table 1). The number of seeds per fruit was the lowest in the control treatment. Therefore, it is evident that an increased number of seeds/fruit was observed with the combined effect of MgSO4 and boron. This finding was in accordance with Venkatramana (2012) who reported that 1% (MgSO4 (10,000ppm) and 0.5% borax (5,000 ppm) increased the number of berries/spike in pepper. However, the concentration of foliar spray used in this experiment is quite low when compared to the concentration used by Venkatramanah (2012).
Furthermore, boron has a pronounced effect on pollen germination, pollen growth and development, which is important in seed set and the resulting fruit, nut and grain production. It was reported that boron increases the fruit set percentage by promoting the pollen germination and elongation of pollen tube and increases carbohydrate supply for the formation of flowers (Abdalla, 2006) and (Singh et al., 2003), and the fruit-set in tomato (Smit and Combrinke, 2005; Desouky et al., 2009), and decreases flower abscission (Smit and Combrink, 2005). Khan, et al. (2010) documented that increased number of seeds per fruit was recorded in barley by the application of Boron and MgSO4 foliar sprays at three growth stages i.e. tillering, booting and milking.

100 seed weight
Maximum 100-seed weight was recorded in T4 which was followed by T3 and T9 (Table 1). T10 was significantly higher than T8, T7 and T6 (Table 1). Minimum 100-seed weight was observed with control treatment (Table 1). Increased number of seeds per fruit might be due to the application of Boron and MgSO4 foliar sprays that led to increase in the 100 seeds weight.
This finding is in agreement with Rerkasem et al. (2004) and Konthoujam Nandini Devi et al. (2012) who reported that increased number of seeds per fruit was due to the foliar application of boron alone (@ 5 kg/ha) and MgSO4 (@ 0.5%) produced increase in the 100 seeds weight. Abdalla (2006) documented that boron increases the percentage of fruit set and the elongation of the pollen tube.However, Khan et al. (2010) revealed that a marked enhancement in 1000 grain weight with the foliar application of B at three growth stages i.e. tillering, booting and milking.

Length of fruits
Length of fruit was significantly influenced by the application of by the application of magnesium and boron. Application of boron and magnesium @ 150 ppm (T9) was superior among the treatments (Table 2). The longest length of fruits (64 mm) was observed from T9 while the shortest length of fruits (22 mm) was found with T0 (Table 2). Length of fruits was significantly increased by the application of zinc and boron (Wojcik and Wojcik, 2003) which enhanced the size or number of cells (Khayyat et al., 2007). The beneficial effects of boron on the length of fruit might be due to its greater involvement in the metabolic processes of the plant such as cell differentiation, cell division, nitrogen metabolism, active soil absorption and photosynthesis. Therefore, it leads to higher metabolic activities.
produced the largest size of fruits with the highest length. But, Sood and Sharma (2004) documented that the maximum length, width and size of fruits, was recorded with the application of the mixture of micronutrients i.e. zinc sulphate, borax, copper sulphate and manganese sulphate. This is due to the contribution of proper utilization of nitrogen and synthesis of amino acids.

Fruit diameter
Result…………- should know the significance level…
The beneficial effect of boron on the diameter of the chilli was reported by Kiranmayi et al. (2014) and Sharma (1999). This finding is concurrence with the studies of Sood and Sharma (2004) who reported that increased fruit size was attained by the application zinc sulphate, borax, copper sulphate and manganese sulphate which are essential for the development proteins and enzymes, that act as a catalyst in plant metabolism and eventually responsible for the growth of the plant. This led to boost the metabolic activity and that in turn resulted in the largest size of fruits with diameter.

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Table 1: Effects of Boron and Magnesium on number of seeds/fruit and 100 seed
weight per plant

Code Treatment Number of seeds 100 seed weight

T1 Control 47.00±0.09d 0.46±0.0088f
T2 B – 50 ppm 60.00±0.03bc 0.52±0.0088e
T3 B – 100 ppm 65.33±0.06b 0.67±0.0057b
T4 B – 150 ppm 72.00±0.01a 0.72± 0.0088a
T5 Mg – 50 ppm 54.00±0.08c 0.46±0.0088f
T6 Mg – 100 ppm 58.33±0.03c 0.51±0.0033e
T7 Mg – 150 ppm 64.00±0.03b 0.56±0.0033d
T8 B + Mg – 50 ppm 68.00±0.08b 0.57±0.00885d
T9 B + Mg – 100 ppm 73.00±0.01a 0.66± 0.0115b
T10 B + Mg – 150 ppm 70.00±0.08a 0.61±0.0088c
F Test

Table 2: Effects of Boron and Magnesium on length and diameter of fruits

Code Treatment Length of fruits (cm) Diameter of fruits (cm)

T1 Control 22 ± 0.466e 18 ± 1.1c
T2 B – 50 ppm 38 ± 0.577d 18 ± 1.1ab
T3 B – 100 ppm 38 ± 0.577d 18 ± 0.566ab
T4 B – 150 ppm 42 ± 1.15c 20 ± 1.15a
T5 Mg – 50 ppm 38 ± 0.577d 17 ± 0.5b
T6 Mg – 100 ppm 40 ± 1.15dc 18 ± 0.866ab
T7 Mg – 150 ppm 42 ± 1.02c 19 ± 0.5ab
T8 B + Mg – 50 ppm 45 ± 0.577b 18 ± 0.566ab
T9 B + Mg – 100 ppm 64 ± 0.577a 20 ± 0.577a
T10 B + Mg – 150 ppm 62 ± 0.577a 19 ± 0.289ab
F Test

Dry weight of fruits per plant
Foliar application of MgSO4 and boron significantly increased the dry weight of chilli. The dry weight of green chilli was remarkably higher (66 g/plant) in plants receiving MgSO4 and boron @ 100 ppm (T9) followed by the dry weights obtained in treatments MgSo4 and boron @ 150 ppm (T10) and 50 ppm (T8), respectively (Table 3). Then, the plants receiving the MgSO4 yield statically similar dry weight of fruits i.e. MgSO4 @ 50, 100 and 150 ppm. However, the minimum dry weight of 32 g/ plant was obtained in the control plots. The dry weight increase due to the foliar application of MgSO4 and boron compared to control was twofold. These results are in line with those of Venkatramana (2002) who reported that foliar application of 1% MgSO4 (10,000 ppm) and 0.5% borax (5000 ppm) increased the yield in pepper. However, Sharma (1999) and Sood and Sharma (2004) showed that foliar application of borax @ 0.5% followed by the mixture of zinc sulphate, borax, copper sulphate and manganese sulphate improved fruit yield in bell pepper. It is also possible that this might be due the contribution of B which raises starch levels of stigma (Singh et al., 2003), regulates the carbohydrates metabolism (Haque et al., 2011) and provides higher carbohydrate for the development of flowers and fruit set (Smit and Combrinke, 2005; Desouky et al., 2009) that led to higher seed setting and translocation of assimilates which increased the size of fruits. Kiranmayi et al. (2014) recorded that chillies received the high concentration of boron produced mean fruit weight and highest green chilly yield than other treatments. In addition, foliar application of 1% MgSO4 (10,000 ppm) also registered in higher yield attributes at Faridkot (AICCIP, 2010).

Table 3: Effects of Boron and Magnesium on dry weight of fruits
Code Treatment Dry weight of fruits/plant

T1 Control 32.0±0.87 g
T2 B – 50 ppm 39.5±1.82 f
T3 B – 100 ppm 44.0±0.77 e
T4 B – 150 ppm 49.0±1.25 d
T5 Mg – 50 ppm 51.0±1.27 dc
T6 Mg – 100 ppm 53.0±0.31 c
T7 Mg – 150 ppm 52.5±1.92 c
T8 B + Mg – 50 ppm 57.0±1.78 b
T9 B + Mg – 100 ppm 66.0±2.99 a
T10 B + Mg – 150 ppm 59.0±0.44 b
F Test

Conclusion
The combined application of Magnesium and boron (T9- 100 ppm) had a significant effect on the number of seeds/ fruit, 100-seed weight, length of fruits, the diameter of fruits and dry weight of fruits/plant. However, sole application of boron @ 150 ppm increased the number of seeds/fruit and length of fruits. Application of Magnesium and boron @ 100 ppm increased the dry weight of green chilli by two-fold than that of control. Therefore, it is concluded that foliar application of Magnesium and boron @ 100 ppm resulted in the highest yield parameters of green chilli.