Physiological Effects of Biological Control Aureobasidium pullulans on Barley Varieties Infected with Rhizoctonia solani

In a greenhouse experiment, barley varieties infected with R. solani showed a significant decrease in plant height, number of leaves, spike number, and number of grains in spike while the treatment of these varieties with biological control Aureobasidium pullulans showed a significant increase in plant height, number of leaves, number of spikes, and number of grains in spike compared to untreated one. moreover, of biological control A . pullulans to R . solani induced a significant improvement in vegetative growth, In the treatment with biological control A . pullulans in addition to R. solani , the highest rate of plant height was found in Aswad two rows variety and reaching 38.81cm. in the second reading, up from 16.52 cm. in the first reading. Among Rehan white six rows that received the treatment with R. solani alone, the lowest plant height, reached 22.08 cm. in the second reading, and it increased from the first reading. Ebaa 265 White six rows variety produced the most number in the treatment with biological control A. pullulans added to R. solani , reaching 8.66 leaves per plant., In the Nour white two rows variety, the lowest leaf rate was 6.6 leaves in the treatment R. solani alone. Aswad two rows variety exhibited the highest spike of barley when treated with biological control A. pullulans alone, reaching 5 spikes in the first, second, and third readings. Among the three readings, there were no spikes in Samir White variety when treated with R. solani alone. the average grains number in spikes, the highest rate was in the treatment of sterilized soil with formalin (control) in Aswad two rows variety which amounted to 7.67 grains in the second reading, up from 7.2 grains in the four reading. Biological control A. pullulans were added to R. solani in the variety Ebaa 265 White six rows, as it, and increased from 4.6 grains in the first to 9.8 in the second reading.


INTRODUCTION
conditions of heat and light, and recording the results during the experimental time from the date of planting 12/12/2021 until 4/5/2022., The experiment included the following treatments: 1-Soil treatment with Rhizoctonia solani alone. 2-Soil treatment with Aureobasidium pullulans alone. 3-Soil treatment with R. solani + A. pullulans 4-Soil treatment with sterile soil (control).

Measurement of height plants (cm)
For all plants in the experimental unit, average plant height was measured from two readings, the first on 16/1/2022 and the second on 21/2/2022.

Number of leaves per plant
On 13/3/2022, the average number of leaves for all plants in the experimental units was counted

Number of spikes per plant
The average number of spikes for all plants of the experimental units of the studied barley cultivars was measured using three readings, the first on 28/2/2022, the second on 3/13/2022, and the third on 4/5/2022.

Number of grains per spike
For all plants in the experimental units of the studied barley cultivars, the average number of grains was calculated, with two readings, the first on 13/3/2022 and the second on 4/5/2022. Statistical analysis of the data was carried out according to SAS system with CRD and Duncan test was used to compare the studied treatments at the level of probability 0.05.

Height of the plant (cm)
Among the barley varieties studied, different treatments have significant effects on plant height, as shown in (Table 1). Among Zanbaka aswad two row varieties, the treatment with biological control A. pullulans in addition with R. solani resulted in the highest plant height, as it reached 15.51 cm in the first reading, which differed significantly in the second reading and reached 27.89 cm, whereas the lowest plant height rate was in the treatment with R. solani alone, which reached 12.32 cm in the first reading and differed significantly in the second reading, resulting in a plant height of 27.71 cm., in the treatment with biological control A. pullulans alone, Aswad variety showed the highest rate of plant height, reaching 19.89 cm in the first reading, and 35.58 cm in the second reading. Plant height in the treatment with R. solani alone was 14.68 cm in the first reading and 34.99 cm in the second reading. According to the variety Nour white two rows, the highest rate of plant height was in the soil sterilized with formalin (control), reaching 21.4 cm in the first reading and 29.13 cm in the second reading, With R. solani alone, the lowest plant height was 17.79 cm in the first reading and 27.37 cm in the second reading.
The Rehaan white six rows variety showed highest plant height in treatment soil sterilized (control), reaching 22.24 cm in the first reading and 32.21 cm in the second reading. The plant height in the treatment with R. solani was 14.78 cm in the first reading and 22.08 cm in the second reading.
It was found that the plant height in Samir white six rows variety was 22.03 cm in the first reading and 34.77 cm in the second reading when biological control A. pullulans alone, while in the first reading, the plant height was 17.78 cm when R. solani was applied alone. The second reading is 30.47 cm, Ebaa 265 white six rows variety showed the highest rate of plant height when treated with biological control A. pullulans alone, reaching 21.76 cm in the first reading and 30.61 cm in the second reading. The lowest plant height rate was seen in the treatment with R. solani alone, which reached 16.57 cm in the first reading and 16.57 cm in the second reading. 24.89 cm second reading, A. pullulans added R. solani in Aswad variety produced an average plant height of 38.81 cm, which was superior to the rest of the treatments.  Fig. (1) show the effect of different treatments on the number of leaves for the studied barley varieties. A biological control A. pullulan alone treatment yielded the highest leaf rate of 7.53 leaves in Zanbaka Aswad two rows' varieties, and R. solani alone treatment yielded the lowest leaf rate of 7.13 leaves. The highest leaf rate was observed in the treatment with biological control A. pullulans added to R. solani, reaching 8.06 leaves, while the lowest leaf rate was observed in the treatment with R. solani alone, at 7.13 leaves. In variety Nour white two rows the highest rate of leaves in the soil sterilized with formalin treatment (control) reaching 7 leaves, and the lowest rate in R. solani alone treatment being 6.6 leaves.

Fig. 1: Effects of different treatments on the average number of leaves of the barley varieties
For variety Rehaan white six rows, the highest leaf rate was 8.2 leaves in the treatment with formalin sterilized soil (control), and the lowest leaf rate was 7.4 leaves with R. solani alone. In variety Samir white six rows, the highest leaf rate was in the treatment of formalin sterilized soil (control), with 7.33 leaves, and the lowest leaf rate was in the treatment of R. solani alone with 6.66 leaves. In variety Ebaa 265 white six rows, the highest leaf rate was 8.66 leaves in the treatment with biological control A. pullulans added to R. solani, and the lowest leaf rate was 7.66 leaves in the treatment with R. solani unit. As Ebaa 265 white six rows variety reached an average of 8.66 leaves, the treatment with biological control A. pullulans added to R. solani was superior to the other treatments.

Number of Spikes
Table (2) shows that different treatments have significantly different effects on the number of spikes of the studied barley varieties, For the variety Zanbaka Aswad two rows, formalin sterilized soil (control) produced the highest spikes, reaching 4.67 spikes in the first reading and 5 spikes in the second and third readings, while the lowest spike rate was 1.33 spikes in the first reading with R. solani alone. The second reading had two spikes and the third reading had 2.67 spikes. With Aswad two rows variety had the highest spike rate in the treatment with biological control A. pullulans unit, reaching 5 spikes in the first, second and third readings, while the lowest spike rate in the treatment with R. solani alone was 2.67 spikes in the first reading and 4.33 spikes in the second and third readings. The variety Nour white two rows of spikes with the highest spike rate in the treatment with biological control A. pullulans alone, reaching 2.67 spikes in the first reading and 5 spikes in the second and third readings, while in the treatment with R. solani alone, the spike rate was the lowest, reaching 0.67 spikes at the first reading and 4.33 spikes at the first reading. The second and third reading, the variety Rehaan white six rows had the highest spike rate in the treatment with biological control A. pullulans in addition to R. solani, reaching 2.33 spikes in the first reading and 5 spikes in the second and third readings. In the third reading, 4.67 spikes were observed, A spike rate was recorded in the third reading for the verity Samir white six rows in both biological control A. pullulans alone treatment and biological control A. pullulans in addition to R. solani treatment, as it reached 0.67 spikes for each treatment, and there were no spikes in the first and second readings, and there were none in the first and second readings with the R. solani.
The verity Ebaa 265 white six rows had the highest spike rate of spikes treated with biological control A. pullulans added to R. solani, with three spikes in the second reading and five spikes in the third reading, and no spikes in the first reading, while the lowest spike rate was in the treatment with R. solani alone. In the third reading, there were 2.67 spikes and no spikes in the first and second readings. In variety Aswad two rows, biological control A. pullulans alone produced 5 spikes in the first, second, and third readings, which was superior to the average number of spikes from the other treatments.

Number of grains/spikes
The results in (Table 3) indicate that different treatments have a significant impact on the number of seeds carried on spikes of the barley verity studied. In Zanbaka Aswad two rows, the highest seed rate was achieved in the treatment with biological control A. pullulans added to R. solani, which reached 7.6 seeds in the first and second readings, and the lowest seed rate was reached in the treatment with R. solani alone, which reached 6.4 seeds in both readings. The highest rate of seeds in verity Aswad two rows was in treatment soil sterilized with formalin (control) at 7.2 seeds in the first reading and 7.67 seeds in the second reading, while the lowest rate of seeds was in the treatment with R. solani alone at 4.87 seeds. Nour white two rows verity showed the highest seed rate in the formalin sterilized soil treatment (control), reaching 4.29 seeds in the first and second readings, and the lowest seed rate in the sole treatment with R. solani, reaching 3.53 seeds in the first and second readings.
Among Rehaan white six rows verity had the highest seed rate and reached 6.4 seeds in the first and second readings when treated with biological control A. pullulans unit, whereas the lowest seed rate was 5.27 seeds in the second reading and no seeds in the first reading when treated with R. solani alone. In the treatment with biological control A. pullulans alone, the verity Samir white six rows showed the highest seed rate, reaching 10 seeds in the second reading, but the lowest seed rate in the treatment with R. solani alone. In the verity Ebaa 265 white six rows produced the highest number of seeds in the treatment with biological control A. pullulans added to R. solani, reaching 4.6 seeds in the first reading and 9.8 seeds in the second reading. In the second reading of the treatment with R. solani, the lowest number of seeds was 5.25, since there were no seeds in the first reading. Biological control A. pullulans added to R. solani in Ebaa 265 white six rows verity increased the seed rate from 4.6 seeds in the first reading to 9.8 seeds in the second reading.

DISCUSSION
Similarly, Al-Kubaisi (2013) found that barley height decreased in soil contaminated with the fungus R. solani, which causes root rot. As a result of the treatment with the fungus R. solani, the height of cultivated barley decreased, and these results were also observed in the study of R. solani effect, A significant reduction in plant height was observed in leguminous plants due to the negative effect of fungus R. solani on the roots of plants because it secretes decomposing enzymes such as phosphatase, cellulase, and pectinase that cause their roots to disintegrate (Al-Turjuman, 2017), Wheat plants infected with the pathogenic R. solani also became shorter (Al-Hamdani, 2021).
A study by Hassan and Saleh (2020) found that cucumber plants treated with the pathogenic fungus Macrophomina phaseolina 59.9 cm shorter than healthy plants, which reached 131.0 cm in the cultivar Magic. This may be due to pathogenic fungi producing decomposing enzymes that penetrate and decompose plant tissues, feeding on their components and decomposition products. Cellulase is one of the most important enzymes, as it degrades the primary defense of plants (cellulose), the compound that makes up cell walls (Agrios, 2005). As a result, the fungus penetrates the cell walls of the plant, affects the plasma membranes, interferes with protein synthesis, plays an important role in causing systemic resistance of the plant (Okereke et al., 2017;Gupta et al., 2017).
It was noted in Fig. (1) that all varieties produced the lowest percentage of leaves when treated with R. solani. It is the result of the negative effect of R. solani on roots that causes the disintegration of their walls, which results in a decrease in their ability to absorb water and nutrients, which affects the plant's growth as a whole (Al-Turjuman, 2017). It is possible that genetic variation between cultivars is responsible for variations in the number and size of leaves on the plant. A greater efficiency of photosynthesis also resulted in a greater wet and dry weight of the vegetative and root systems, It might be the result of increasing the efficiency of the leaves, as they contain auxins that assist in cell division and root formation, as plant growth hormones increase the resistance of the plant, reduce the effort on the plant, increase the growth and development of roots and branches, increase the efficiency of photosynthesis, and increase vegetative growth (Al-Amri, 2014).
It is clear from the results that the pathogenic fungus R. solani reduced the number of spikes and seeds in the spike, as it caused a significant reduction in the number of spikes and seeds (Abboud et al., 2017). According to Weinhold and Sinclair (1996), when wheat plants are treated with the pathogenic fungus R. solani, the number of spikes and grains decrease significantly, and the root walls disintegrate as a result of the enzymes it secretes (Phosphatase, Cellulase, Pectinase). In addition, it causes a weakness in the absorption of nutrients, causing weak plant growth, the absence of spikes, and incomplete formation of seeds in the ears, either empty or atrophic, resulting in a small number of seeds (Abboud et al., 2017). study of Hassan and Awad (2017), the number of spikes and seeds treated with bio-control A. pullulans increased and this could be attributed to the ability of this fungus to increase the readiness of elements or its secretion of plant hormones that stimulate growth and encourage resistance to disease. In the effect of the fungus Trichoderma harzianum on the productivity of the bean plant, treatment with the bio-resistant T. harzianum resulted in higher yields and fresh weights of beans. In this study, the fungus T. harzianum demonstrated its ability to reduce the rate and severity of infection through biological control. It stimulates plant growth and resistance to disease by increasing chitinase activity, peroxidase activity, and polyphenol oxygenase activity.

CONCLUSIONS
Among the barley varieties studied, different treatments have significant effects on plant height, Zanbaka Aswad two row varieties, the treatment with biological control A. pullulans in addition with R. solani resulted in the highest plant height, A biological control A. pullulan alone treatment yielded the highest leaf rate of 7.53 leaves in Zanbaka Aswad two rows varieties, and R. solani alone treatment yielded the lowest leaf rate, that different treatments have significantly different effects on the number of spikes of the studied barley varieties, For the variety Zanbaka Aswad two rows, formalin sterilized soil (control) produced the highest spikes.
The results indicate that different treatments have a significant impact on the number of seeds carried on spikes of the barley verity studied. In Zanbaka Aswad two rows, the highest seed rate was achieved in the treatment with biological control A. pullulans added to R. solani,