Effect of Different Levels of Soil Salinity on Vegetative Growth Indicators of Four Genotypes of Broad Bean Vicia faba L.

A field experiment for the winter season (2022-2023) was carried out in the field of the Department of Crops / Faculty of Agriculture - Al-Qasim Green University, to find out the effect of different levels of soil salinity on vegetative growth indicators for four genetic structures of beans using the design of complete random sectors according to factor experiments, as the main panels included Genotypes (local, Turkish, Spanish, Dutch) while the secondary panels included three levels of soil salinity (2, 6 and 9 ds/m). The results indicated that there are significant differences at the level of probability of 5% of the studied qualities, as the Turkish variety outperformed the average vegetative growth, as it gave the highest average in the characteristic of plant height, number of branches, number of leaves, leaf area, root length and dry weight of the root system, either the local variety outperformed in the characteristic of the number of days of planting up to 50% flowering., leaf area, root length and dry weight of the root system, Compared to the salt level (9 ds/m), which achieved the lowest average of these traits, which differed significantly from the comparison treatment by achieving the lowest number of days of cultivation up to 5% flowering.


Introduction Broad Bean
Vicia faba L is one of the most important leguminous crops and the most widespread in the world, due to its high nutritional importance and is grown in various countries with the aim of obtaining juicy green pods and dry seeds that are used as a basic food after grass crops for humans and as animal feed, as well as beans are a staple food for the population of poor countries, especially North African countries and the countries of the Middle East for its high content of proteins 25-35% [1].The Genotypes of beans differ in vegetation according to the nature of their growth, and they vary in the height of their stems and branches, which leads to the difference in the shape of the plant as well as the difference in the size of the seeds, some of which have large seeds and some with small seeds, as well as the difference in the seed range of nutrients and the percentage of protein, and this difference is often due to the nature of the variety, genetic composition and environmental conditions [2].Many plants are exposed to different types of environmental stresses, and salt stress is one of the most dangerous types of stress, because it affects plant growth, as it interferes with plant metabolic processes, which negatively affects plant growth and may lead to its death, and agricultural land affected by salinity constitutes about 23% of the world's arable land [3].If plants are exposed to salt 1259 (2023) 012111 IOP Publishing doi:10.1088/1755-1315/1259/1/012111 2 levels higher than these levels, their growth and physiological functions are affected by dysfunction due to the stress of salt accumulation in the root area and thus leads to a decrease in the quality of the yield.Salinity not only reduces the condition of the ready-made elements, but also reduces their transfer to the plant growth parts, which affects the vegetative growth indicators of the plant and the growth of flowers [4].Various physiological and biochemical plants [5].Saline stress reduces metabolic processes and reduces the absorption of nutrients such as potassium and calcium [6], thus high salinity determines plant growth.Many studies have been conducted on the effects of salt stress on the vegetative growth indicators of the bean plant, and the results of these studies have indicated that salinity greatly affects these indicators.[7] In her study carried out to evaluate the Giza 87 variety in three different levels of salinity (6.9, 8.7 and 14.8 ds/m) during two consecutive agricultural seasons (2016-2017 and 2017-2018), it was explained that salinity significantly reduced the vegetative growth indicators, as the high saline levels (14.8 dS/m) achieved the lowest average plant height of 31.33 cm and the number of branches reached 2.33 plant branches -1 , while the saline level (6.9dS/m) achieved the highest average of these characteristics of 92.33 cm and 4 plant branches -1 On the sequence.As noted [8].[9] When studying the effect of different levels of salinity on the growth of genetic structures of beans, it was found that the salinity levels (0, 1, 2 and 3 ds/m) had negative effects on dry weight of the root, as the comparison treatment gave the highest weight of 0.57 g compared to the levels of 3 ds/m) the lowest weight of 0.35 g.This study also showed that the genotypes of beans have different behaviors in terms of responding to artificially increased salinity levels using different salt sources indicating that the beans' response to salt levels is a specific genetic pattern.[10] found significant differences in all vegetative growth characteristics during his study in which he carried out and used four Genotypes of beans (Spanish, Turkish, French and Cypriot) as the French variety excelled in recording the highest average plant height, number of branches, leaf area and dry weight of the root total amounted to 67.93 cm, 6.32 plant branches -1 , 3403 cm 2 plant -1 and 6.90 g plant -1 respectively, Compared to the lowest average recorded by the Turkish variety for all the above traits was 54.26 cm, 5.94 plant branches1-and 3019 cm2 and 5.83 g plant -1 respectively.While [11] there were no significant differences between the genetic structures (Dutch mulch second generation, local Syrian variety, Spanish second generation) in the root length trait, giving an average of 32.25, 32.00 and 30.67 cm respectively.The aim of this study is to assess the difference between the genetic structures of beans in tolerating different levels of saline stress.

Materials and Methods
The experiment was carried out in the field according to the experiments of the worker in the fields of the Faculty of Agriculture, Al-Qasim Green University.Then the field was divided into three replicates according to the design of the complete randomized sectors (RCBD), each repeater includes 12 experimental units, so the total number of experimental units is 36 units, the experiment included two factors, the first factor includes four genetic structures of beans (local, Spanish, Turkish and Dutch) respectively, The second factor included three concentrations of soil salinity, which is a treatment compared to levels of 2 desmins (S0) and the second level with levels of 6 desmins (S1), while the third level was levels of 9 desmins (S2), the planting process took place on 1/11/2022.

Preparing the Land for Agriculture How to Work
 Preparing the panels, which are closed and lined with nylon with an area of 2×3 m and a depth of about 50 cm. A soil with a salinity of( 2 ds/m) was brought to be used as a comparative treatment. Two soil samples were brought from areas with levels of 6 and 9 ds/m . The seeds of the genetic structures are planted in the boards on lines between one line and another 35 and between Joura and another 25 and the crop service operations are irrigation, patching, loosening and weeding as needed.After the plants reached full maturity, including blackening and falling leaves and blackening of the pods, the harvesting process was carried out successively according to the ripening dates of the studied Genotypes .After entering and tabulating the results, the data were analyzed statistically and for all the studied traits using the method of analysis of variance according to the Genstat program, and the least significant difference test (LSD) was used, and at the level of probability 0.05 to compare the arithmetic averages [12].

Characteristics of Vegetative Growth Studied
 Number of days from planting up to 50% flowering: calculated from planting until the flowering rate reaches 50% and based on the number of plants in the experimental unit. Plant height (cm): The distance in centimeters between the soil surface and the base of the inflorescence of the main stem. Number of branches per plant (plant branch -1 ): The side branches of each plant were calculated at harvest. Number of leaves (leaf -1 ): Depending on the number of leaves per plant before the harvest period. Leaf area (cm 2 ): The leaf area was calculated method [13] (leaf area = length × width × 0.57) then (one leaf area = leaf area × number of leaflets) and then the leaf area was calculated = leaf area × number of leaves in the plant. Root length cm: The roots of the plants were extracted from the soil at a depth of 30 cm and washed with water after removing the vegetative branches, and then the root length was taken with a tape measure. Dry weight of the root system (g plant -1 ):The roots of the plants were extracted from the soil and at a depth of 30 cm and washed with water after removing the vegetative branches and dried the root system of the plants naturally, and after the weight was proven was weighed and then calculated the average dry weight of the root total of one plant.

Number of Days from Planting up to 50% Flowering (Day)
The results of Table (1) indicate the existence of significant effects between the genetic structures of beans and salinity levels in the characteristic of the number of days of planting up to 50% flowering (day), in which it is noted that the local variety significantly outperformed the rest of the Genotypes as it achieved the lowest flowering period of 73.22 (day), while the Dutch variety achieved the longest flowering period of 51.44 (day), and may be the reason for the variation in the characteristic of the number of days of planting To 50% flowering to a difference in a variety, as some Genotypes may differ among themselves in vegetative growth, so they are shorter than others, so we note that they bloom early and these results are similar with [14].
As for the effect of salinity levels on this characteristic, the salt level (9 Decimens M-1) significantly outperformed the rest of the levels, as it achieved the lowest growth period of 53.25 (days) compared to the comparison treatment (2 Decimans M-1), which achieved the longest period of 70.67 (day).

Plant Height (cm)
The results of Table (2) indicate the existence of significant effects between the genetic structures of beans and salinity levels in the characteristic of plant height cm, the Turkish variety outweighed significantly over the rest of the Genotypes , as it achieved the highest average plant height of 86.61 cm, compared to the Spanish variety, which achieved the lowest average plant height of 64.01 cm, and that these differences in plant height may be attributed to the impact of Genotypes and the extent of adaptation of these Genotypes with the surrounding environmental conditions, or may return The reason is the nature of the different gene expression between one variety and another, and this is what he referred to [15] As for the effect of salinity levels in this characteristic, the comparison treatment achieved the highest plant height of 99.76 cm compared to the salt levels (9 ds/m), which recorded the lowest average plant height of 53.84 cm.

Number of Branches (branch plant -1 )
The results of Table (3) indicate the existence of significant effects between the genetic structures of beans and salinity levels in the characteristic of the number of branches (branch plant -1 ), in which it is noted that the Turkish variety significantly outperformed the rest of the Genotypes as it achieved the highest average number of branches amounted to 5.53 (branch plant -1 ), Compared to the Spanish variety, which achieved the lowest average number of branches of 4.01 (branch plant -1 ), the difference between the Genotypes is due to the genetic variation among them in their ability to branch.These findings are consistent with the findings [16] and [17].As for the effect of salinity levels in this trait, the comparison treatment gave the highest number of branches of 6.20 (branch plant -1 )while the salt level (9 ds/m) achieved the lowest average number of branches of 3.27 (branch plant -1 ).

Number of Leaves (leaf plant -1 )
The results of Table (4) indicate the existence of significant effects between the genetic structures of beans and salinity levels in the characteristic of the number of leaves (leaf plant -1 ), in which it is noted that the Turkish variety significantly outperformed the rest of the Genotypes , as it achieved the highest average number of leaves amounted to 155.89 (leaf plant -1 ) , while the Dutch variety achieved the lowest average number of leaves of 73.93 (leaf plant -1 ) , and the reason is due to the genetic nature of the variety associated with the genes responsible for the degree of gene expression of these genes ، The reason is due to the genetic nature of the variety associated with the genes responsible for the degree of genetic expression of these genes, where it was noted that the Genotypes of beans vary among themselves in the number of leaves, but it has a significant effect on the yield and this change is due to the difference in the number of branches per plant [18] As for the effect of salinity levels in this trait, the comparison treatment gave the highest number of leaves amounting to 144.80 (leaf plant - 1 ) while the salt level (9 ds/m) achieved the lowest average number of leaves (72.11 (leaf plant -1 ).

Leaf Area (cm 2 )
The results of Table (5) indicate the existence of significant effects between the genetic structures of beans and salinity levels in the characteristic of Leaf area (cm 2 ) , in which it is noted that the Turkish variety significantly outperformed the rest of the Genotypes recorded the highest average of the Leaf area amounted to 2986.9 (cm 2 ) ,Compared to the Spanish variety, which achieved the lowest average leaf area of 1878.8 (cm 2 ) , and perhaps most of the Genotypes of beans give a leafy area determined by the number of leaves, the width and length of the leaflet and the number of leaves, so this characteristic is controlled by the genetic and environmental factor mainly in determining the leaf area of the plant.Therefore, this trait is mainly controlled by the genetic and environmental factor in determining the leaf area of the plant.As for the effect of salinity levels in this characteristic, the comparison treatment gave the highest paper area of 3441.7 (cm 2 ) compared to the salt level (9 ds/m), which achieved the lowest average paper area of 1337.3 (cm 2 ).
Table 5.Effect of Salinity levels on leaf area (cm 2 ) of broad bean varieties.

Root Length (cm)
The results of Table (6) indicate the existence of significant effects between the genotypes of beans and salinity levels in the characteristic of root length (cm), the Turkish variety achieved a significant superiority over the rest of the Genotypes , as it achieved the highest average root length of 31.71(cm), while the Spanish variety achieved the lowest average root length of 25.29 (cm).As for the effect of salinity levels in this characteristic, the comparison treatment gave the highest average root length of 35.57(cm) compared to the salt level (9 decemens m-1), which achieved the lowest average root length of 21.55 (cm).Table 6.Effect of Salinity levels on root length of broad bean varieties.

Dry Weight of the Root System (g)
The results of Table (7) indicate the existence of significant effects between the genotypes of beans and salinity levels in the characteristic of the dry weight of the root total (g), the Turkish variety significantly outperformed the rest of the Genotypes , as it achieved the highest average dry weight of the root total amounted to 14.06 (g) compared to the Dutch variety, which achieved the lowest average dry weight of the root total amounted to 8.62 (g).The reason for the increase may be due to the ability of the variety to benefit from the compounds in the rhizospheric region and invest them efficiently in increasing the activity of enzymes and hormones responsible for growth and thus better development of the root system.As for the effect of salinity levels on this characteristic, the comparison treatment achieved the highest mean dry weight of the root system of 16.82 (g) while the salt level (9 decemens M-1) achieved the lowest average dry weight of the root system of 6.66 (g).
Table 7.Effect of Salinity levels on Dry weight of the root system (g)of broad bean varieties.It is clear from the above figures (1, 2, 3, 4, 5, 6) for vegetative qualities (50% flowering, number of branches, number of leaves, leaf area, root length and dry weight of the root system) that there is a direct relationship between salinity levels and quantitative characteristics (vegetative growth qualities), we note from this relationship a significant decrease in vegetative growth indicators at the salt level (9 ds/m) Perhaps the reason for this is due to the effect resulting from the increase in salts in the soil, resulting in less absorption of water by the plant, which in turn leads to the entry of less absorption of nutrients, which negatively affects the processes of nutritional construction and vital activities within the cell and thus affects the effectiveness of photosynthesis and respiration [19], and the most important negative effect is the increase in the production of free radicals that cause disruption of cellular food structure.And the oxidation of some internal structures of the components of the cell, such as the cell wall, and the osmotic pressure increases with increasing salinity, which leads to a decrease in water voltage, which hinders the transfer of water through the root system, and this clearly reflects on the indicators of vegetative growth, or this decrease may be due to the accumulation of sodium ions and chloride reaches a certain degree of toxicity, which causes a lack of activity of meristem tissue and prevents division and elongation of cells [20].In general, salinity reduces the growth rate, such as the length of roots and vegetative branches Table (5 and 2) and the length of the roots is affected by salt more than vegetative branches because the harmful effects of salinity can inhibit the activity of the cambium which leads to reduced exposure to the carrier leading to the small size and short length of the root [21].Salinity levels also affect the leaf area as well as the decrease in the number of leaves Table (4 and 5) and the small paper area, the high salinity caused the stiffness of the edges of the leaves and then their fall [22] and [23].

Conclusions
We conclude from:  This study that the Turkish variety excelled in vegetative growth indicators due to its adaptation to the Iraqi environment. High salinity levels reduce vegetative growth rates, as their growth and physiological functions are affected by dysfunction due to the stress of salt accumulation in the root zone and thus lead to a decrease in the quality of the yield.

Figure 2 .
Figure 2. Effect of salinity levels on No of branches (branch plant -1 ).

Figure 4 .
Figure 4. Effect of salinity levels on Number of leaves (leaf plant -1 ).

Figure 6 .
Figure 6.Effect of salinity levels on dry weight of root system (g).

Table 1 .
Effect of Salinity levels on No of days from planting up to 50% flowering (day) of broad bean varieties.

Table 2 .
Effect of Salinity levels on height plant (cm) of broad bean varieties.

Table 3 .
Effect of Salinity levels on Number of branches (branch plant -1 )of broad bean varieties.

Table 4 .
Effect of Salinity levels on Number of leaves (leaf plant -1 )of broad bean varieties.