Biological Control of some Weeds with Aqueous Extract of Wheat ( Triticum aestivum L

Allelopathic effects of wheat aqueous extract were studied on seeds germination and seedling growth of four weeds Canary grass ( Phalaris minor L.), Mallow ( Malva rotundifolia L.), Sweet clover ( Mililotus indica Mill)


MATERIAL AND METHODS
Study was conducted at Biology Department/ College of Science/ University of Mosul in 2020, about the activity of wheat plant residues towards four species of weed and its effect on their germination and growth.
The wheat residues collected for testing their allelopathic activity after harvested from fields of Mosul, crushed, aqueous extracts were prepared at a concentration 5,10,15% (Abbas and Hussain, 2020), the effects of concentration 5, 10, 15% of the plant residues of Wheat (Triticum aestivum L.) on germination and early seedling growth of Canary grass (Phalaris minor L.), Mallow (Malva rotundifolia L.), Sweet clover (Mililotus indica Mill), and Wild oats (Avena fatua ), (Table 1) were studied in a greenhouse glasshouse. For this, 10 seeds were cultured in plastic pots with diameter 20 cm, height 25 cm, at depth 0.5 cm from the surface of the soil for each of weed, then irrigated with water, and put in a glass house at a temperature of 20 ± 2Cº, after 8 days germination calculation, and after 60 days of germination, plants were cut off, separated shoot from roots. inhibition percentage was calculated according to the following equation: Chung et al., 2001). Leaf area (cm 2) = leaf length ×max width leaf× 0.905 (Kemp et al., 1966). 5. Leaves Number / plant. 6. Plant dry weight (g). Each of the following characteristics was measured according to the aforementioned source:

Statistical Analysis
Experiment was carried out according to Random Complete Block Design (R.C.B.D.) as a global experiment and data statistical analysis according to SAS program. Duncan multi-range test was used at a 0.05 probability of differentiation between treatments average Antar (2010).

RESULTS AND DISCUSSION
The results in (Table 2) show inhibition effect in seed germination of the four weeds (Canary grass (Phalaris minor L.), Mallow (Malva rotundifolia L.), Sweet clover (Mililotus indica Mill) and Wild oats (Avena fatua ( ) by effect of aqueous extract of Wheat (Triticum aestivum in all treatments, the inhibition was in all concentrations but was higher effect in 15%, highest percentage inhibition was (44%) observed in Canary grass treated with aqueous extract at 15% by so then wheat considers is one crops to inhibit weed growth by allelopathic interactions, effect on growth of weeds resulted released allelochemical compounds from the different parts for plants Jabran (2018).
Result showed Canary grass is more sensitive for treatment compared with other weeds, While Wild oats was less sensitive that due to differences in genotype of weeds (Hussain et al., 2018a).  Table (3) Indicated a reduction in Shoot length of the four weeds that treated with aqueous extract of Wheat (Triticum aestivum L.), all results shows that the highest percentage inhibition in Canary grass at concentration 15% of Wheat extract that is (78.34%), these results consistent with Refreshing (2001). that showed wheat extract prevented weed germination, results are shown reduction effect increased by concentration increased, it is apparent that Mallow was more sensitive for treatments, While the less sensitive was Canary grass may be due that to differences in genotype.

Table 3: Effect of wheat aqueous extract in Shoot length(cm) of some weeds
The study demonstrated that wheat aqueous extracts of exhibited significant inhibitory effects on roots length of all test species (Table 4). Earlier works have also reported use allelopathic effect for improved food quality and increasing crop production, wheat (Triticum aestivum L.) is chief field crop in the north of Iraq, while weeds are reason in loss around 45-50% of yield (Ali, 2013). Hussein et al. (2018) reported that wheat residues reason inhibitory in germination rate of Sochus oleraceus L., and that inhibitory effect of wheat can be due to Salicylic acid, P-hydroxy benzoic acid they were diagnosis in wheat residues, which are known to inhibit the germination and growth of the receptor plant. Aqueous extract of wheat was displaying various degrees from inhibit effect in dry weight of all weeds that effect depends on a concentration. the greatest inhibition was observed at the 15% w: v concentration (Table 5). Perhaps the reason for decrease in dry weight can be due to presence of allelopathic compounds such as alkaloids; Glycosides; tannins, that may be interfered with various growth mechanisms and caused inhibition in photosynthesis process, which led to low dry weight, or it is due to the plant's sensitivity for these compounds and to genetic differences between the varieties (Hussain, 2010).

Table 5: Effect of wheat aqueous extract in Plant Dry Wight (gm) of some weeds
Results in (Table 6) showed that aqueous extracts used in this study caused inhibit at effect in leaf area at all weed the treated by aqueous extraction of Wheat, and that effect can be due to allelopathic compounds effect in cell division, elongation, and effect at IAA activity AL-Jehaishy (2017), the table show increased inhibition effect at concentration 15%. the highest inhibition observed in Canary grass by effect the aqueous extract at concentration 15% is (94.55 %). The results in (Table 7) showed effect efficiency of sprayed by aqueous extracts of Wheat (Triticum aestivum L.), in weed control (%), saw the highest Percentage efficiency at the treatments in reducing the weeds caused by aqueous extraction of wheat at concentration 15% in Canary grass. Results show difference in weeds response to inhibitory effect of crop residues, that difference may be due to differences in genetic factors and plant nature, or may be due to activity of allelopathic compounds that releases from Wheat (Triticum aestivum L.) including organic acids, aldehydes and aromatic acids Aromatics, flavonoids, tannins, alkaloids or terpenoids, and steroid as well as some toxic gases Putnam and Tang (1986). Which have revealed their presence in wheat residues Hussein et al. (2018) this may be justify crops inhibitory effect. Results in (Table 8) estimated that the addition of wheat aqueous extract in soil has a significant effect on the status of nitrogen, phosphorous and potassium in weeds compared with control. wheat aqueous extract at 15% gave the greatest values. these results may be due to effect of wheat aqueous extract may be increased absorption and transportation of N, P, K to plant.  Table 8: Effect of wheat aqueous extract in soil content of (N, P, K) CONCLUSIONS Residues at concentration 5, 10, 15 % on germination and early seedling growth of weeds, results showed the inhibitory effect of aqueous extract of wheat was h at higher 5% . of EWC (%). from results that Mallow was more sensitive for treatments, While the less sensitive was Canary.