Influence of humic acid on growth and yield of strawberry cv . Chandler

A study on “Influence of humic acid on growth and yield of strawberry cv. Chandler” was conducted at Newly Development Horticultural Farm, The University of Agriculture Peshawar, Pakistan during 2014. The experiment was carried out using Randomized Complete Block design (RCBD) with one factor replicated thrice. Three levels of humic acid (1.5, 3.0 and 4.5ml L) were sprayed on strawberry plant after 30 days of transplanting. The data were recorded on various growth and fruit yield of strawberry at various stages. The analyzed data showed that more number of fruits (28.3) plant, total carotenoids (17.84 mgg ), total lycopene content (0.0244 mgg) were recorded at 3mlL humic acid and minimum percent fruit waste (0) was recorded with humic acid at 4.5mlL, while titratable acidity was found non-significant. It was concluded from the above results that the strawberry cv. Chandler could be sprayed with 3.0 mlL of humic acid in order to obtain better growth and quality fruit production under the agroclimatic condition of Peshawar.


Introduction
Strawberry (Fragaria ananassa belongs to family Rosaceae, subfamily Rosoideae.The garden strawberry was first bred in Brittany, France, in the 1750s which is derived from a cross between F. virginiana from Eastern North America and F. chiloensis from Chile and Argentina .The word "straw" referred to the practice of covering the plant with straw to protect it from freezing [1].Strawberries are mostly grown in many parts of the world including Japan, USA, Mexico, Italy and Germany.In Pakistan strawberry are cultivated in plains of Ghotki, Panu Akil, Ranipur, Shaheed Benazirabad, Gilgit, Chitral, Kaghan, Kohistan, Swat, Mingora, Multan, Narowal, Bhawalpur, Chistian, Sialkot and Faisalabad.In Khyber Pakhtunkhwa, it grows in hilly areas especially in Swat and Murree and also in plain areas of Peshawar in the month of October.274 [12].Keeping in view the problems related to strawberry growth, yield and importance of humic acid, a study on "Influence of humic acid on growth and yield of strawberry cv.Chandler" was carried out with the objective to evaluate the optimum concentration of humic acid for better growth and yield of strawberry cultivar.

Materials and methods
A study on "Influence of Humic acid on growth and yield of strawberry cv.Chandler" was carried out at Newly Development Horticulture Farm, The University of Agriculture Peshawar, Pakistan in October 2014.

Experimental design and treatment combination
The experiment was laid out using Randomized Complete Block Design (RCBD) with one factor replicated three times.Strawberry plants were sprayed with humic acid (1.5, 3.0 and 4.5mlL -1 ) after 30 days of transplantation.

Planting materials
The field was prepared and divided into 12 Plots.Each plot size was 36ft 2 (3.34m 2 ) and in each plot had 32 plants of strawberry.The runners of strawberry cv.Chandler were brought and planted in the month of October, 2014 on ridges at a distance of 1ft (30cm) between plant to plant and 2ft (60cm) between row to row.Hoeing, weeding and irrigation were done on the basis of their needs and wheat straw was used as mulch for protection from frost.

Preparation of humic acid solution and its application time
A solution of one liter was made from 18% liquid humic acid for all treatment levels and then foliar spray of humic acid were occure three times after 30 days of transplantation on each experimental plot with duration of 10 days interval.The data for following attributes of strawberry was recorded accordingly.

Number of fruits plant -1
Fruit were counted by taking randomly five plants, and the average was calculated.Percent fruit waste Fruits were selected in each treatment on the basis of visual observation of fruits in each picking and were determined with the help of following formula.

Percent titratable acidity
Percent titratable acidity of strawberry juice was determined by the standard method of

Number of fruits plant -1
Number of fruits plant -1 was significantly influenced by different concentration of humic acid (Table 1).The mean data table showed that highest number of fruits (28.3) was noted in plant with the application of humic acid at 3mlL -1 followed by (26.3) number of fruits at 1.5ml L -1 humic acid.
The lowest number of fruits (22.6) was recorded in control treatment.Humic acid significantly increase the rate of photosynthesis, respiration and plant harmone like activity in plants as result flower concentration increase which boost up fruit ratio in plant [16].[17] reported that humic acid contain cytokinins and their application outcome in increased endogenous cytokinin and auxin levels which possibly leading to improve growth of plant as result number of berries per plant increases.[18] Suggested that foliar application of humic acid led to improvement of quantitative and qualitative characteristics of strawberry (chlorophyll content, fruit number, total yield of plant, TSS and fruit firmness).Similarly the results are in line with the findings of [19] who treated strawberry plant with humic acid and vermicost and found a significant effect of number of fruits.[20] Investigated the effect of humic acid and sea weed extract on cucumber and found a significant effect of number of fruits.[21] studied effect of humic acid from different source on growth of green house plants and found a significant effect of number of fruits.

Percent fruit waste
Percent fruit waste was significantly influenced by foliar spray of humic acid.The mean data analyzed that maximum percent fruit waste (12) was observed in plants treated with humic acid at (1.5mlL -1 ) followed by percent fruit waste (4) with humic acid at 3mlL -1 .While minimum percent fruit waste (0) was observed in plants treated with humic acid at 4.5mlL -1 .
The results are in relation with findings of [22] who treated strawberry with humic acid between bloom and fruit harvest and found a significant role of humic acid on fruit waste Percent titratable acidity Data regarding percent titratable acidity shows that different level of humic acid had non-significant effect on the percent titratable acidity of strawberry fruit (Table 1).
Total carotenoids (mgg -1 ) Total carotenoids were significantly influenced by foliar application of humic acid (Table 1).The mean data revealed that highest carotenoids content (17.84mgg -1 ) was recorded in plant fruit treated with humic acid at 3mlL reported that total carotenoids increased with application vermicompost treatments.
[28] observed a higher total carotenoids in organically grown sweet peppers than in integrated and conventional peppers.
Total lycopene (mgg -1 ) Foliar spray of humic acid significantly influenced total lycopene content of strawberry (Table 1).The mean data analyzed that that the highest lycopene content (0.0244mgg -1 ) was recorded in plants treated with humic acid at 3.0 mlL -1 followed by lycopene content (0.0243mgg -1 ) at 1.5mlL -1 humic acid.While lowest lycopene content (0.0019mgg -1 ) was recorded in plants treated with humic acid at 4.5mlL -1 .The significant difference among means of total lycopene content might be due to significant response of humic acid on carotenoids content.In support of our findings, [29] have reported an increase in lycopene and beta carotene contents of pepper fruit in response to HA application.

Conclusion and recommendations
It was concluded from the above results that humic acid significantly influenced most of the studied attributes of strawberry.Hence, humic acid could be applied after 30 days of transplantation of strawberry runners at 3 mlL -1 for better quality production of strawberry fruit in the agro climatic region of Peshawar valley.
Total carotenoids and lycopene were estimated by the method described by Zakaria et al. [14].Data analysis Randomized Complete Block Design (RCBD) was used for data analysis and least significant differences test (LSD) at 5% was used for mean separation when F-value was significant.Statistical software Statistix (8.1) was used for calculating ANOVA and LSD value [15].