## 3 Results
### PEG Stress Tolerance Based on Callus Growth Traits  
The overarching goal of this experiment was to investigate the drought tolerance of six rice genotypes under in vitro callus initiation and to test their reactions to the various amounts of PEG by estimating the characteristics of CI, CFW, and CDW. The six genotypes responded markedly to different PEG concentrations. Figure 1 illustrates the box plots of six callus growth traits and comparative analyses of variations between the control group and stress groups (T0.50, T1.0, and T1.50) across all genotypes. CI, CFW, CDW, CL, and CW traits showed significant decreases compared to the control treatment and these characteristics gradually decreased from minimal drought stress (T0.50) to severe drought stress (T1.50), while CWT showed a significant increase compared to the control group. As shown in Table 4, significant variations were illustrated among all genotypes for all callus growth parameters under control and stress conditions. In the control condition (T0.00), the data ranged from 66.67% (Red Bazyan) to 100% (White Bazyan), 1 (Red Bazyan) to 1.40 g (White Bazyan), and 0.44 (Red Bazyan) to 0.76 g (White Bazyan) for CI, CFW, and CDW, respectively. At the T0.50 condition, a highly significant difference in callus growth parameters was displayed among the tested genotypes. The highest values of CI, CFW, and CDW were found in White Bazyan (100%), Choman (1.18 g), and White Bazyan (0.54 g), respectively. For the T1.00 treatment, the maximum values were recorded by Choman, Shawre, and White Bazyan for CI; Choman for CFW; and Shawre for CDW. At a high concentration of PEG (T1.50), the responses of six genotypes varied between 53.33% and 86.67% for CI, 0.30 and 0.91 g for CFW, and 0.16 and 0.38 g for CDW. High CI, CFW, and CL were observed in the Choman genotype at a high level of PEG. As indicated by the results, the minimum values of CI, CFW, and CDW were revealed by Red Bazyan. These findings indicate that the rice genotypes react differently to drought and the responses of genotypes depend on PEG concentrations. This suggests the different genotype potentials for callus growth parameters. In addition, as the amount of PEG was increased in the medium, there was a decline in CFW and CDW. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**SSR Marker** & \begin{tabular}{c} **Chromosome** \\ **Number** \\ \end{tabular}  & \ \begin{tabular}{c} **Amplicon** \\ **Size (bp)** \\ \end{tabular}  & \begin{tabular}{c} **Number of** \\ **Allees** \\ \end{tabular}  & **PIC** & **DI** & **PI** \\ \hline RM10793 & 1.00 & 140.00–160.00 & 3.00 & 0.51 & 0.57 & 0.25 \\ RM16 & 3.00 & 140.00–180.00 & 4.00 & 0.57 &  
Concerning the callus cell dimension parameters (Figure 2 and Table 5), a remarkable and important divergence was exhibited among the six rice genotypes depending on PEG concentrations. Maximum values of CL, CW, and CWT in the control condition were observed by Shawre (47.80 \(\upmu\)m), Shware (33.23 \(\upmu\)m), and Red Bazyan (2.37 \(\upmu\)m), respectively. At the low PEG level (T0.50), the reaction of the six genotypes ranged from 22.03 (Kalar and Shaware) to 33.5 \(\upmu\)m (Choman) for CL, 10.73 (Shawre) to 19.77 \(\upmu\)m (Choman) for CW, and 1.93 (Gwll Swr) to 2.43 \(\upmu\)m (Choman) for CWT. The Choman genotype with 47.80, 16.20, and 3.33 \(\upmu\)m was noticed to have maximal values of CL, CW, and CWT, respectively, at the T1.50 concentration. Further, the ranking method was conducted based on the callus growth parameters to identify the best genotypes according to the method proposed by [26], using different evaluated traits. Based on this approach, the average sum of ranks (ASRs) was used as  
Figure 1: Box charts of growth characters of the kernel-derived call from six rice genotypes, revealing the significant divergences between normal and stress conditions. (**A**). callus induction (CI), (**B**). callus fresh weight (CFW), (**C**). callus dry weight (CDW), (**D**). cell length (CL), (**E**). cell width (CW), and (**F**). cell wall thickness (CWT).