EFFECT OF NITROGEN, ROOT STIMULATOR, AND GIBBERELLIC ACID ON A SPECIFIC CHARACTERISTICS OF PEACH SAPLINGS

827  EFFECT OF NITROGEN, ROOT STIMULATOR, AND GIBBERELLIC ACID ON A SPECIFIC CHARACTERISTICS OF PEACH SAPLINGS A. R. K. Altotanje A. T. Joody Researcher Assist. Prof. Ahmedriadh305@yahoo.com ahmedjoody@yahoo.com Dept. of Hortic. and land. Coll. of Agric. Engine. Scie. – University of Baghdad ABSTRACT This study was aimed to evaluate the effect of nitrogen fertilizer, organic root stimulator and gibberellic acid on some growth characters of peach saplings cv. Red June for two consecutive seasons 2017-2018 at College of Agricultural Engineering Science, University of Baghdad. Different nitrogen (Urea 46%N) rates (0,50,75 gm) with three concentrations of organic stimulator (0,0.5,1 gm.L -1 ) and two rates of Ga3 (0,50 mg.L -1 ) were applied in a factorial scheme (3×3×2). Results revealed that the individual and interactive effect of applying nitrogen, root stimulator and GA3 significantly increased the studied characters, the interaction at N2D1G1 has improved the leaf dry weight (42.00%), shoot dry weight (61.33 %), Relative water content (RWC) (60.00%), N (2.68%), P (0.414%) and K (1.94 %) for season 2017, while the treatment N2D2G1 had the highest values at leaf dry weight (46.00 %), shoot dry weight (64.00%), RWC (74.00%) and leaf content of N (2.39%), P (0.56%), and K (1.99%) for season 2018.


‫العراقية‬ ‫الزراعية‬ ‫العلوم‬ ‫مجلة‬
. Nitrogen is a nutrient required in great quantities by Peach trees, It has a direct effect on vegetative growth, yield, and fruit quality; therefore the setting of dose is necessary to ensure the best nutritional balance (8). Abdelsattar and Mohammed (1) Mentioned that nitrogen application on pomegranate has a significant effect on leaf dry weight and N, P, and K leaf content, Thokchom et al. (20) found that applying nitrogen fertilizers on Apricot trees cv. New Castle significantly increased N leaf content, Liu et al (9) recorded that the Application of Nitrogen with two different irrigation regimes increased relative water content (RWC). In recent reports the application of organic fertilizers improved mineral fertilizers affect on soil fertility and enhanced vegetative growth and fruit production (21). Hidayatullah et al (15) mentioned that the application of Humic acid on apple trees cv. Red delicious enhanced the N, P, and K leaf content of and branch numbers, Al-ahbaby (2) found that the application of sea weed extract on grapes enhanced leaf dry weight and N, P, K leaf content. GAs are tetracyclic diterpenoid compounds stimulating seed germination, juvenility, cells division and enlargement (19). Al-rashdi et al (6) recorded that foliar application of Ga3 on grape increased the N, P, K leaf content, Al-rawi et al (7) found that Ga3 spray on peach trees Cv. Peento enhanced the leaf dry weight and leaf content of N, P, and K. All given above, this study was aimed to evaluate the effect of nitrogen, root stimulator and Gibberellic acid on vegetative growth of peach saplings CV. Red June.

MATERIALS AND METHODS
The Present study was performed on ''Red June'' peach trees, all of which were almost uniformed in vigor, grown under conventionally accepted practices. A factorial experiment randomized complete block design (RCBD) with 5 replicates was conducted on 90 trees planted over 5 rows with 3.5 meters between each row, occupied with 18 trees per row, spaced by 2.5 meters at the College of Agricultural Engineering Sciences, University of Baghdad peach orchard for two consecutive seasons 2017-2018.
In this experiment different concentrations of Nitrogen (0,50,75 gm tree 1 -), organic stimulator (0,0.5,1 mg L 1 -) and two rates of GA3 (0,50 ppm), were applied in April, then repeated three times (beginning of April, May, and June) except for disper root which started in the middle of March and repeated bi-weekly until June. Shoot dry weight, leaf dry weight were found using the formula (dry weight\wet weight)×100, while N were measured according to Haynes(13) method, and P according to Olsen and Sommers (18), also K leaf content were found using Haynes (13) method, and relative water content (RWC) according to Wu et al (22). All parameters were measured and subjected to computerized statistical analysis of variance (ANOVA) and means of treatments were compared using L.S.D at 0.05 .

RESULTS AND DISCUSSIONS Leaf dry weight (%)
Results in table (1) shows that the application of Nitrogen at 75 gm gave the highest value in both growth seasons (38.17 , 40.89) respectively , as well as the Root stimulator at 0.5 gm.L -1 gave a significant value for season 2017 reached (37.06 %) while the concentration 1 gm.L -1 gave (41.89 %) in season 2018, also GA3 gave significant values (34.41 , 39.15 %) for the consecutive seasonal growth. The tripartite interaction showed the highest value in season 2017 at N2D1G1 reached (42.00 %) while the treatment N2D2G1 produced the highest value for season 2018 reached (46.00 %), Nitrogen's effect on construction of chlorophyll pigment which is important in the process of photosynthesis, increases the proportion of processed nutrients and their accumulation in plant tissues causing an increase in dry weight (8), The effect of root stimulator on dry weight may be due to the increase in leaf area and chlorophyll content relatively increasing manufactured materials which accumulated in branches and leaves (11), or could be due to the effect of GA3 increasing root growth, leaf area and leaf dry weight (19). These results are in agreement with (4) and (7) on peach and (15) on apricot.

Shoot dry weight (%)
Based on the results in Table 2 the concentration 75 gm has the highest outcome peaked at (50.00, 56.17) for both seasons respectively, and the application of root stimulator at 0.5 gm.L -1 had a most significant rate (50.22 %) in season 2017 while the concentration 1 gm.L -1 granted the highest outcome in season 2018 (51.33 %). Meanwhile the foliar application of GA3 gave a significant value in both growth seasons peaked at ( 46.89, 53.48 %) respectively. The interaction treatment N2D1G1 granted the most significant value (61.33 %) in season 2017 while the treatment N2D2G1 gave the highest value in season 2018 peaked at (64.00 %). The Nitrogen effect in construction of chlorophyll pigment which is important in the process of photosynthesis, increases the proportion of processed nutrients and their accumulation in plant tissues causing an increase in dry weight (8), The effect of root stimulator on dry weight may be due the effect of amino acids in enzyme activity which effects on accelerating the absorption and transmission of nutrients within the plant and then increase the process of photosynthesis which leads to accumulation of numerous nutrients in plant tissues and increase the dry weight (10). Table 3 shows that the application of Nitrogen at 75 gm produced the highest rate in both seasons (53.11, 60.78 %) respectively, While the application of root stimulator at 0.5 gm.L -1 had the highest value in season 2017 reached (55.50 %) while the concentration 1 gm.L -1 had the most significant outcome (66.61 %) in season 2018, as well as the GA3 in both growth seasons had a significant rate of RWC peaked at ( 51.78, 57.85 %) respectively, the interaction N2D1G1 had the highest value in season 2017 peaked at (60.00 %) while the treatment N2D2G1 gave a significant rate in 2018 reaching (74.00 %), The individual or interactive effect of nitrogen, root stimulator and Gibberellic acid can be due to their role in increasing root growth and positively increasing water absorption, which increases relative water content in the leaves (12) (8)(19), these results agreed with (9).

Leaf Nitrogen content(%)
Results from Table 4 shows that the application of Urea at 75 gm gave significant rate peaked at (2.19, 1.85 %) for both seasons, The soil application of root stimulator at 0. . The effect of Nitrogen may be due to its role in cells division and vegetative and root system growth which positively increases the absorption efficiency of soil nutrients and increase leaf P concentrations (8), or it may be due to the role of Humic acid in root nutrient availability, leading to an increase in nutrients absorption and accumulation in leaves (11), or it may be due to the effect of Gibberellic acid in increasing the nutrients in leaves or may be due to its role in activating cell division and elongation and increasing the absorption of nutrients from the roots (19), these results are in agreement with the results of other researches (1) on Pomegranate and (7) on Peach and (14) on apple. Leaf Potassium content(%) Results in Table 6 shows that the application of Nitrogen at 75 gm had the highest value  1.99 %). The effect of Nitrogen may be due to its role in cells division and vegetative and root system growth which positively increases the absorption efficiency of soil nutrients and increasing the leaf K concentrations (8).or it may be due to the role of Humic acid in root nutrient availability, leading to increase nutrient absorption and accumulates in the leaves(11),or it may be due to the effect of Gebberellic acid in increasing the nutrients in the leaves may be due to its role in activating the division and elongation of cells and increase the absorption of nutrients from the roots (19), these results are in agreement with the results of other researchers (1) on pomegranate and (7) on peach and (14) on apple.