The chickpea (Cicer arietinum L.), also known as the Bengal gram or Garbanzo bean, is one of the many pulses grown around the world and is well known as a potential crop to satisfy the protein-hunger. It is the third most significant pulse crop behind dry beans and peas (FAO, 2008). It is a great source of energy because it is packed with fibre, vitamins, minerals, and potentially healthy phytonutrients (Ibrikci et al., 2003; Jukanti et al., 2012). According to FAOSTAT (2019), there were around 13.7 million hectares of chickpeas grown worldwide, producing 14.24 million metric tonnes at a productivity of 1038 kg ha−1. For a number of years, India has been the world’s top producer of chickpeas, making up 70 per cent of total production (agricoop.nic.in). |
The estimated 3.7 million tonnes of annual output losses worldwide resulting from abiotic stressors represent an average loss of 40-60 per cent. Today, among other abiotic stresses, soil salinity is recognized as a significant crop loss factor (Ashraf et al., 2008). However, because the annual loss in chickpea production is estimated to be between 8 and 10 per cent, salinity is considered to be one of its very sensitive factors. The majority of the time, chickpeas are cultivated in semi-arid, irrigated soils where water loss during the dry seasons frequently results in salt deposits in the top layers of the soil. This built-up salt lowers the soil’s osmotic potential, causing water stress that brings on nutritional imbalances that harm the plants’ metabolism and induce cell death (Hasanuzzaman et al., 2013). Chickpeas under salinity stress experience lower seed germination, seedling vigour, root and shoot length, photosynthetic activity, and nitrogen fixation, all of which affect growth and yield (Egamberdieva et al., 2015; Khan et al., 2017). Abd-Alla et al. (2019) observed that salt levels between 25 and 150 Mm severely hindered chickpea growth and yield. |
Identification and selection of salt-tolerant genetic resources have attracted a lot of attention over the past few decades due to the detrimental effects that salt stress has on chickpea growth and yield. In order to distinguish between genotypes that are sensitive to or tolerant of salinity stress, a number of agro-morphological traits have been reported. In light of the foregoing description, the main goals of the current study were to identify salt-tolerant chickpea genotypes from a large set of chickpea germplasm accession samples and assess crucial morphological and physiological features under salinity stress. |
Top Materials and Methods Selection of experimental material Twenty high-yielding desi-type chickpea lines in total (Table 1) were picked up for the current study from the germplasm bank at the Department of Genetics and Plant Breeding, University of Calcutta. Here, three distinct salinity levels (150, 200, and 300 mM) were used in the form of NaCl solution to impose the salinity stress. The control treatment consisted of no salts (0 mM). These lines were sown in a randomized block design with three replications for each treatment on 17.07.2020 and underwent screening for both germination percent in Petri dishes at the early seedling stage and yield characteristics in a pot experiment with mature plants. Screening at the early seedling stage Viable, surface-sterilized (1.0% NaOCl solution) seeds of all chickpea lines were placed in Petri dishes with 10 seeds/line/treatment and allowed to sprout on filter paper soaked in 15 ml of saline solutions at various concentrations (0, 150, 200, and 300 mM), in a growth chamber with a mean temperature of 20 °C. Parafilm was used to tightly enclose the Petri dishes in order to reduce evaporative loss and maintain the level of salt. Germination percentage was assessed four days after seeding, and seedling vigour indicators such as root and shoot length were assessed after 7 days. Screening at different salinity levels for yield parameters in the matured plant (pot experiment) Viable, surface-sterilized seeds of all the chickpea germplasms were planted on July 17, 2020, in pots filled with sandy loam soil under greenhouse conditions with a mean temperature of 20 °C. Normal irrigation practices were kept up until 15 days after sowing (DAS). After this time, a fertigation technique was used to inflict salt stress using the protocol of Manasa et al. (2017). For stressed plants, 500 ml of each salt solution was added in accordance with the soil’s field capacity in order to provide the three levels of stress stated above while preventing leaching. Normal water was used to irrigate the control plants. Similarly, stress was applied seven times at the following intervals: 15, 35, 45, 55, 65, 75, and 85 DAS. Normal irrigation was carried out periodically as needed. On five randomly chosen plants/lines/treatments, various agro-morphological parameters, including nodules per plant, days to maturity, number of branches per plant, leaf area index, number of pods per plant, pod length (cm), number of seeds per pod, 100 seed weight (g), and seed yield/plant (g), were recorded at the time of maturity. Data on different salinity parameters were recorded as follows:
Grouping of 20 chickpea lines was done on the basis of percent reduction in seed yield parameters under 300 mM salinity treatment. Statistical analysis The mean values of each parameter were taken for statistical analysis. All the statistical analyses were done using IBM SPSS version 20.0 software. Top Results and Discussion Germination percentage and plant growth at different salinity levels at the early seedling stage Salinity stress decreased the percentage of germination in seeds. The average percentage reduction in seed germination above the control (0 mM) varied from 0-20 per cent in 150 mM, 5-39 per cent in 200 mM, and 20-50 per cent in 300 mM. (Table 2). Therefore, a higher saline level greatly lengthens the germination period and decreases the germination percentage. The likely cause of this phenomenon is an increase in sodium/chloride ions in the soil, which results in an outside osmotic potential and ion toxicity and ultimately prevents the hydrolytic enzymes from being activated, causes turgor loss, prevents apo-plastic acidification, and further reduces seed germination and seedling growth (Mohammed, 2007; Murillo-Amador et al., 2002; Garg and Chandel, 2011). Under various salt levels, the seedling growth in all of the studied lines exhibited significant differences. Under 150, 200, and 300 mM salinity stress, it was discovered that seedling length was reduced by 21-84, 34-88, and 48-92 per cent, respectively. The genotypes Virat and WBG 29 showed the highest level of reduction (92%) at 300 mM (Table 2), whereas Digbijoy showed the lowest level of reduction (48%) in seedling growth. This could be attributed to the steady decline in chlorophyll, carotenoid pigment levels, and chlorophyll fluorescence intensity that results from decreased electron transport function and instability of the pigment-protein complex (Promila and Kumar, 2000). In high saline conditions, the total leaf area and stomatal aperture are also reduced (Nandini and Subhendu, 2002). Yield parameters at different salinity levels in matured plants All agro-morphological parameters in the experiment demonstrated decreased performance and a statistically significant variance between genotypes with the increasing salinity level. At 150 mM, the values of the percent reduction in plant height and branches/plant ranged from 4 to 23 and 1-22 per cent, respectively; at 200 mM, they were 4 to 31 and 1-36 per cent, respectively; and at 300 mM salinity stress, they were 6 to 55 and 1-41 per cent, respectively. At 300 mM salinity stress the maximum reduction in plant height and branch number was recorded in DCP 92-3 (55%) followed by ICCV 10 (40%) and ICCV 10 (41%) followed by Virat (35%) respectively, while minimum reduction over control was reported in Digbijoy (6%) followed by IC 268900 (11%) and Digbijoy (1%) followed by IC 268900 (9%) and Avrodhi (9%), respectively. When it came to the number of nodules and pods per plant as well as pod length, the values of stressed plants likewise showed a substantial decrease among the accessions. Virat reported the greatest reduction in the number of nodules per plant (45% in 150 mM, 68% in 200 mM, and 88% in 300 Mm), while Digbijoy reported the least reduction (5% in 150 mM, 21% in 200 mM, and 34% in 300 Mm). In terms of the average value of pods per plant, pod length, and seeds per pod, Annigeri and Digbijoy recorded the lowest reductions for each of these three parameters, whereas ICCV 10 in terms of pods/plant and pod length, and Virat in terms of seeds per pod, recorded the largest reductions over controls under 300 mM salinity stress. With regard to all the tested lines and tested parameters, higher salinity levels showed greater reductions compared to controls. While Digbijoy experienced the lowest drop in seed yield/plant compared to the control (11.8%), ICCV 10 had the greatest reduction (58.9%) under 300 mM saline stress (Table 3). The differences across germplasms could result from both hereditary variations and specific genetic influences (Uddin et al., 2009; Win et al., 2011). As salinity stress rose, the percentage of reduction gradually increased [Kaya and Arif (2003), Mahdavi and Modarres Sanavy (2007), Sehrawat et al. (2014)] (Fig. 1). The other agro-morphological elements influence seed yield, which is a polygenic trait. The main goal of every breeding programme is to increase seed yield. According to earlier research by several experts, salt-tolerant accessions were identified to be less impacted by higher salinity stress and might yield more seeds than others (Ashraf and Waheed, 1990; Sarkar and Kundagrami, 2016; Uddin and Hossain, 2018). Therefore, all of the examined lines were divided into three main classes: Tolerant 0-35%, Moderately Susceptible 36-50%, and Highly Susceptible 50% based on the percent loss of seed yield characteristics over control under 300 mM saline stress (Table 4). Results revealed that the highest number of accessions i.e., 10 were found in the category moderately susceptible followed by 7 accessions in the tolerant and 3 in highly susceptible. Therefore, comparing the seed yield performance of all the tested germplasms it is found that the germplasms namely IC 268900, Digbijoy, Dahod yellow, Avrodhi, IC 268863, WBG 29, and B115 were categorized as tolerant germplasms, Vijoy, Virat and ICCV 10 were categorized as highly susceptible germplasms and rest were categorized as moderately susceptible germplasms (Table 4). It’s interesting to note that when the results of all the testing parameters were added up, Digbijoy recorded a lesser reduction under salinity stress than other accessions, whereas ICCV 10 and Virat, in that order, recorded the highest reduction. Therefore, these germplasms may serve as a useful stock for future breeding initiatives aimed at creating chickpea lines that are tolerant to salinity. Correlation and regression analysis Correlation and regression analysis are used to depict the relationships among several agro-morphological factors and salt tolerance under three different salinity loads. The results of a correlation study showed a substantial positive relationship between seed yield and germination percentage, seedling length, plant height, number of branches per plant, number of pods per plant, and pod length for lower salinity stresses (150 and 200 mM), however with the increase in salinity, no such significant association was identified (Table 5). There was no significant relationship between plant height, leaf area index, pod length, or 100 seed weight and the salt tolerance index (Standard Evaluation Score), suggesting that these characteristics may not be a strong predictor of salinity tolerance. However, the number of branches/plant did not significantly correlate with the tolerance index at lower salinities (150 and 200 mM), but a significant negative correlation (-70) was found with an increase in salinity level (Table 4). This suggests that as the number of branches increases, the tolerance index (Standard Evaluation Score) may gradually decrease, indicating that the germplasms are more tolerant to the environment (Ali et al., 2014). Furthermore, regression assessment revealed a substantial but unfavourable relationship between salt tolerance and number of pods/plant, pod length, number of seeds/pod, and seed yield/plant, demonstrating that salt-tolerant germplasms may have larger numbers of pods/plant, pod length, seeds/pod, and seed yield/plant (Table 6). These desirable parameters can take part in the future breeding programme for saline soils by getting introduced into the susceptible lines. Additionally, these results were combined with past research by Peng et al. (1999), Ali et al. (2014), and others. These studies further established the significance of these parameters as valuable selection criteria for screening the salt tolerance in terms of seed yield among different germplasms. Top Conclusion From comparing the seed yield performance of all the tested germplasms, it can be concluded that Digbijoy, IC 268900, Dahod yellow, Avrodhi, IC 268863, WBG 29 and B 115 may be used as tolerant germplasms and Vijoy, Virat, and ICCV 10 as highly susceptible germplasms for future breeding programmes. The variations of the agro-morphological parameters among the germplasms were lower at low salinity stress (150 mM) than at high salinity stress (300 mM). In addition to this, as per correlation and regression study, while choosing salt-tolerant genotypes of chickpea in greenhouse conditions, plant breeders may emphasize the number of pods/plant, pod length, number of seeds/pod, and seed yield/plant. These desirable parameters also take part in the future breeding programme for saline soils by getting introduced into the susceptible lines. |
Top Figure | Figure 1.: Percent reduction of different agro-morphological parameters under different salinity stress (mM NaCl solution)
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Tables | Table 1.: Description of Chickpea lines under study.
| | Sl. No. | Germplasm | Seed yield /plant (g) | | 1 | Digbijoy | 18.97 | | 2 | GCP 105 | 18.07 | | 3 | IC 268971 | 17.87 | | 4 | IC 268900 | 17.39 | | 5 | Virat | 16.38 | | 6 | WBG 29 | 15.92 | | 7 | ICCV 10 | 15.82 | | 8 | Radhey | 15.68 | | 9 | Avrodhi | 15.13 | | 10 | DCP 92-3 | 15.05 | | 11 | Vijoy | 14.21 | | 12 | G 24 | 14.14 | | 13 | IC 268863 | 14.07 | | 14 | Dahod yellow | 13.9 | | 15 | B 115 | 13.84 | | 16 | IC 268943 | 13.16 | | 17 | Mahamaya 1 | 13.01 | | 18 | Annigeri | 12.99 | | 19 | Anuradha 39/2 | 12.76 | | 20 | RSG 888 | 12.63 |
| | | Table 2.: Variation in percent reduction of plant growth at different salinity levels in early seedling stage
| | Germination (%) | Seedling Length (mm) | | 150 mM | 200 mM | 300 mM | 150 mM | 200 mM | 300 mM | | Digbijoy | 0 | 5 | 20 | 21 | 34 | 48 | | GCP 105 | 0 | 10 | 30 | 71 | 76 | 80 | | IC 268971 | 10 | 15 | 35 | 71 | 73 | 81 | | IC 268900 | 0 | 10 | 50 | 30 | 38 | 52 | | Virat | 20 | 35 | 45 | 84 | 88 | 92 | | WBG 29 | 10 | 20 | 30 | 79 | 82 | 92 | | ICCV 10 | 20 | 39 | 50 | 78 | 84 | 89 | | Radhey | 0 | 15 | 35 | 61 | 66 | 72 | | Avrodhi | 10 | 20 | 40 | 74 | 74 | 80 | | DCP 92-3 | 10 | 20 | 30 | 61 | 66 | 72 | | Vijoy | 0 | 20 | 40 | 44 | 58 | 66 | | G 24 | 10 | 20 | 40 | 70 | 73 | 81 | | IC 268863 | 0 | 20 | 30 | 73 | 78 | 83 | | Dahod yellow | 10 | 20 | 30 | 72 | 79 | 85 | | B 115 | 10 | 20 | 40 | 82 | 84 | 88 | | IC 268943 | 10 | 20 | 30 | 77 | 82 | 87 | | Mahamaya 1 | 0 | 15 | 35 | 69 | 76 | 85 | | Annigeri | 10 | 20 | 40 | 53 | 64 | 75 | | Anuradha 39/2 | 0 | 30 | 40 | 73 | 79 | 85 | | RSG 888 | 0 | 20 | 40 | 71 | 77 | 84 | | Mean | 6.00 | 20.40 | 37.20 | 65.92 | 72.52 | 79.61 | | S.Em.± | 1.03 | 0.89 | 1.07 | 2.09 | 2.18 | 2.06 | | Range | 0-20 | 5-39 | 20-50 | 21-84 | 34-88 | 48-92 |
| | | Table 3.: Variation in % reduction of nodules/plant, plant height, branch/plant, leaf area index, pods/plant, pod length, seeds/pod and seed yield/plant at different salinity level in matured plant.
| | Nodule/plant | Plant height | Branch/plant | Leaf area index | Pods/plant | Pod length | Seeds/pod | Seed yield/plant | | 150 mM | 200 mM | 300 mM | 150 mM | 200 mM | 300 mM | 150m M | 200 mM | 300m M | 150m M | 200 mM | 300 mM | 150 mM | 200 mM | 300 mM | 150m M | 200m M | 300m M | 150m M | 200m M | 300m M | 150m M | 200m M | 300mM | | Digbijoy | 5 | 21 | 34 | 5 | 4 | 6 | 1 | 1 | 1 | 2 | 4 | 3 | 8 | 14 | 26 | 1 | 3 | 6 | 3.6 | 2 | 3 | 1.5 | 12 | 11.8 | | GCP 105 | 33 | 50 | 67 | 8 | 19 | 12 | 18 | 20 | 29 | 11 | 12 | 13 | 20 | 20 | 34 | 4 | 4 | 7 | 4 | 7 | 11 | 10.7 | 26.2 | 38.5 | | IC 268971 | 35 | 40 | 65 | 10 | 18 | 26 | 12 | 16 | 28 | 5 | 10 | 27 | 25 | 34 | 40 | 8 | 9 | 12 | 6.6 | 16.5 | 25.3 | 20.4 | 43.6 | 47.5 | | IC 268900 | 20 | 13 | 40 | 6 | 10 | 11 | 3 | 7 | 9 | 10 | 16 | 21 | 12 | 24 | 35 | 5 | 4 | 6 | 2.3 | 6 | 12 | 9.6 | 26.4 | 20.5 | | Virat | 45 | 68 | 88 | 8 | 18 | 35 | 20 | 32 | 35 | 18 | 21 | 29 | 28 | 32 | 39 | 18 | 25 | 32 | 18.6 | 24.9 | 39.5 | 26.9 | 41.5 | 56.3 | | WBG 29 | 44 | 67 | 78 | 12 | 13 | 19 | 7 | 17 | 22 | 4 | 7 | 11 | 22 | 25 | 31 | 10 | 11 | 12 | 6.2 | 16.6 | 11.2 | 9.9 | 22.6 | 32.9 | | ICCV 10 | 46 | 62 | 80 | 23 | 31 | 40 | 22 | 36 | 41 | 20 | 25 | 30 | 29 | 35 | 48 | 19 | 28 | 35 | 19.7 | 25.3 | 35.2 | 23.6 | 32.9 | 58.9 | | Radhey | 29 | 57 | 71 | 15 | 22 | 25 | 12 | 26 | 30 | 8 | 11 | 25 | 25 | 33 | 35 | 12 | 21 | 32 | 6.8 | 15.2 | 24.6 | 16.9 | 30.4 | 44.7 | | Avrodhi | 0 | 17 | 50 | 4 | 10 | 14 | 4 | 7 | 9 | 3 | 3 | 3 | 17 | 26 | 28 | 2 | 6 | 7 | 1.5 | 5.5 | 0 | 3.2 | 16.9 | 32.5 | | DCP 92-3 | 29 | 43 | 71 | 23 | 26 | 55 | 9 | 19 | 21 | 15 | 22 | 28 | 19 | 22 | 30 | 4 | 7 | 10 | 0 | 2.2 | 7.5 | 0 | 32.9 | 44.9 | | Vijoy | 25 | 63 | 88 | 10 | 13 | 16 | 3 | 7 | 10 | 13 | 13 | 13 | 8 | 20 | 30 | 1 | 3 | 7 | 4.3 | 5.6 | 7.3 | 4.3 | 42.5 | 54.6 | | G 24 | 33 | 50 | 83 | 16 | 18 | 20 | 4 | 6 | 10 | 1 | 5 | 6 | 14 | 22 | 46 | 17 | 24 | 23 | 5.3 | 10.9 | 17.8 | 3.4 | 27.8 | 44.9 | | IC 268863 | 50 | 63 | 75 | 19 | 22 | 24 | 11 | 14 | 15 | 0 | 2 | 1 | 8 | 14 | 27 | 12 | 14 | 17 | 2.8 | 4.9 | 8.3 | 3.3 | 22.4 | 32.6 | | Dahod yellow | 44 | 67 | 78 | 14 | 26 | 29 | 6 | 12 | 18 | 7 | 8 | 9 | 14 | 22 | 33 | 11 | 13 | 14 | 5.2 | 5.2 | 13.3 | 4.5 | 15.6 | 30.8 | | B 115 | 40 | 60 | 80 | 10 | 18 | 24 | 21 | 22 | 23 | 12 | 15 | 17 | 16 | 23 | 32 | 13 | 15 | 17 | 4.5 | 8.6 | 15.3 | 1.5 | 17 | 35.1 | | IC 268943 | 17 | 17 | 50 | 15 | 20 | 22 | 3 | 6 | 10 | 12 | 13 | 17 | 14 | 20 | 28 | 7 | 5 | 7 | 4.4 | 5.5 | 3.4 | 5.1 | 29.7 | 46.7 | | Mahamaya 1 | 38 | 42 | 66 | 12 | 15 | 29 | 15 | 21 | 27 | 10 | 17 | 20 | 13 | 21 | 29 | 9 | 10 | 18 | 7.2 | 14.2 | 25.3 | 9.2 | 27.7 | 45.4 | | Annigeri | 25 | 38 | 75 | 13 | 19 | 24 | 20 | 28 | 31 | 10 | 13 | 13 | 4 | 11 | 19 | 3 | 4 | 5 | 4 | 13.4 | 7.8 | 18.6 | 31.7 | 40.1 | | Anuradha 39/2 | 17 | 17 | 67 | 15 | 19 | 22 | 18 | 22 | 27 | 3 | 2 | 16 | 13 | 19 | 27 | 8 | 9 | 16 | 3.8 | 21.9 | 4 | 2.2 | 24.4 | 49.1 | | RSG 888 | 40 | 60 | 80 | 20 | 24 | 28 | 5 | 10 | 20 | 3 | 2 | 3 | 4 | 15 | 27 | 6 | 7 | 11 | 5.1 | 9.2 | 1.6 | 0.2 | 24 | 47.5 | | Mean | 30.75 | 45.75 | 69.3 | 12.9 | 18.25 | 24.05 | 10.7 | 16.45 | 20.8 | 8.35 | 11.05 | 15.25 | 15.65 | 22.6 | 32.2 | 8.5 | 11.1 | 14.7 | 5.79 | 11.03 | 13.67 | 8.75 | 27.41 | 40.76 | | S.Em.± | 1.8 | 2.3 | 1.6 | 0.7 | 1.2 | 1.2 | 1.3 | 1.5 | 2.0 | 0.6 | 0.8 | 1.0 | 1.3 | 1.3 | 1.7 | 0.8 | 0.9 | 1.1 | 1.2 | 1.5 | 1.8 | 2.1 | 1.6 | 1.6 | | Range | 0-50 | 13-68 | 34-88 | 4-23 | 4-31 | 6-55 | 1-22 | 0-36 | 1-41 | 0-20 | 2-25 | 1-30 | 4-29 | 11-35 | 19-48 | 1-19 | 3-28 | 5-35 | 0-19.7 | 2-25.3 | 0-39.5 | 0-26.9 | 12-43.6 | 11.8-58.9 |
| | | Table 4.: Grouping of twenty chickpea lines on the basis of percent reduction in seed yield parameters under 300 mM salinity treatment.
| | Sl. No. | Salt response | % Reduction | Name of genotypes | | I | Tolerant | 0-35 | Digbijoy, IC 268900, Dahod yellow, Avrodhi, IC 268863, WBG 29, B115 | | II | Moderately susceptible | 36-50 | GCP 105, Annigeri, Radhey, G 24, DCP 92-3, Mahamaya 1, IC 268943, RSG 888, IC 268971, Anuradha 39/2 | | III | Highly susceptible | >50 | Vijoy, Virat, ICCV 10 |
| | | Table 5.: Correlation matrix among the agro-morphological parameters at different salinity stress.
| | | Germina tion (%) | Seedling Length (cm) | Nodule/plant | Plant Height (cm) | Branch/plant | Leaf Area Index | Pod/plant | Pod Length (cm) | Seed/Pod | 100 Seed Weight (g) | Seed Yield/plant (g) | | Seedling | 150 | 0.08** | | | | | | | | | | | | Length | 200 | 0.09** | | | | | | | | | | | | (cm) | 300 | −0.08 | | | | | | | | | | | | Nodule/plant | 150 | −0.03 | 0.30** | | | | | | | | | | | 200 | 0.20* | 0.09 | | | | | | | | | | | 300 | 0.21 | 0.26 | | | | | | | | | | | Plant Height | 150 | −0.13 | 0.01 | 0.09* | | | | | | | | | | (cm) | 200 | 0.00 | −0.23 | 0.16 | | | | | | | | | | 300 | 0.00 | −0.08 | −0.05 | | | | | | | | | | Branch/plant | 150 | 0.14 | 0.32 | 0.21 | −0.40* | | | | | | | | | 200 | 0.17** | 0.28 | −0.16 | −0.52* | | | | | | | | | 300 | 0.20 | 0.17 | 0.12 | −0.21 | | | | | | | | | Leaf Area | 150 | 0.15 | 0.08 | 0.35 | 0.17 | 0.20 | | | | | | | | Index | 200 | 0.04 | 0.11 | 0.22 | −0.14 | 0.27 | | | | | | | | 300 | −0.02 | 0.21 | 0.21 | −0.20 | 0.33 | | | | | | | | Pod/plant | 150 | 0.26 | 0.14** | 0.14 | −0.10 | 0.30** | 0.36 | | | | | | | 200 | 0.35 | 0.08 | 0.22 | −0.03 | 0.23** | 0.40 | | | | | | | 300 | 0.19 | 0.17 | 0.20 | −0.27 | 0.13** | 0.38 | | | | | | | Pod Length | 150 | 0.19 | 0.15 | 0.06 | −0.51 | 0.56* | 0.05 | 0.37 | | | | | | (cm) | 200 | 0.20 | 0.15 | −0.15 | −0.37 | 0.53* | 0.08 | 0.33 | | | | | | 300 | −0.13 | 0.18 | 0.23 | −0.03 | 0.26* | 0.16 | 0.10 | | | | | | Seed/ | 150 | 0.00 | 0.30 | −0.03 | 0.29 | 0.08 | 0.12 | 0.23 | −0.06 | | | | | Pod | 200 | 0.02 | 0.34 | 0.00 | −0.09 | 0.26 | 0.15 | 0.20 | 0.12 | | | | | 300 | 0.13 | 0.18 | 0.10 | −0.18 | 0.18 | 0.20 | 0.53 | 0.04 | | | | | 100 Seed | 150 | −0.14 | −0.04 | 0.17 | 0.19 | 0.08 | 0.23 | 0.19 | 0.19 | 0.00 | | | | Weight | 200 | −0.11 | −0.06 | −0.03 | 0.00 | 0.08 | 0.26 | 0.24 | 0.17 | −0.02 | | | | 300 | 0.11 | 0.07 | 0.22 | −0.14 | −0.01 | 0.29 | 0.18 | 0.12 | 0.08 | | | | Seed Yield/plant | 150 | 0.35** | 0.13** | 0.22 | −0.22** | 0.37** | 0.20 | 0.39** | 0.29* | 0.16 | 0.07 | | | 200 | 0.16* | 0.05* | −0.05 | −0.16* | 0.41* | 0.01 | 0.10* | 0.27* | 0.07 | 0.12 | | | 300 | −0.16 | 0.37 | 0.39 | −0.11 | 0.08 | 0.06 | 0.04 | 0.41 | −0.19 | 0.12 | | | Tolerance | 150 | −0.06* | −0.08* | −0.26* | −0.55 | −0.69 | −0.03 | −0.65** | −0.06 | −0.19* | −0.12 | −0.19** | | Index | 200 | −0.09 | −0.16* | −0.10 | −0.43 | 0.86 | −0.05 | −0.58* | −0.06 | −0.23* | −0.18 | 0.23** | | 300 | −0.06 | −0.29 | −0.35 | −0.69 | −0.70* | −0.06 | 0.30* | −0.08 | −0.56 | −0.09 | 0.29** |
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| indicates 1% level of significance; | indicates 5% level of significance | | | Table 6.: Regression coefficients among agro-morphological parameters at different salinity levels and constant (dependent variable: tolerance index).
| | Parameter | Tolerance index | Germination (%) | Seedling Length (cm) | Nodule/plant | Plant Height (cm) | Branch/plant | | 150 mM | 3.29NS | −0.03NS | 0.29NS | −0.11NS | 0.59 | 0.15NS | | 200 mM | 3.86 | −0.09NS | 0.48NS | −0.21NS | 0.82NS | 0.29 | | 300 mM | 4.19** | −0.12NS | −0.81NS | −0.49NS | 0.91 | 0.41NS | | Leaf Area Index | Pod/plant | Pod Length (cm) | Seed/Pod | 100 Seed Weight (g) | Seed Yield /plant (g) | | 150 mM | 0.12NS | 0.18 | 0.55 | 0.23NS | 0.20 | 0.46 | | 200 mM | 0.24NS | 0.23NS | 0.76NS | 0.54* | 0.13 | 0.59NS | | 300 mM | 0.35 | 0.56** | 0.91** | 0.71** | 0.14 | 0.88** |
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