*3.2. Analysis of Variance Showed Significant Variation in Green Super Rice*

To study the significant differences between the genotypes and heat treatment, the morpho-physiological data were subjected to analysis of variance (ANOVA). Results showed highly significant variations (*p* < 0.001) among the genotypes for all the studied parameters except NDVI (Table 1). Heat stress also showed a highly significant effect on the studied parameters except GW and NDVI. The interactions of genotypes × treatment were also highly significant (*p* < 0.001) for PH, SY, HI, and PFP. GY varied significantly (*p* < 0.05), while TPP, GW, GL, and NDVI were non-significant (Table 1). It is important to note that ANOVA showed significant effects of heat stress on most traits; however, heat stress affected PH, GW, GL, PFP, and NDVI in only a few genotypes and did not show a considerable effect overall (Figures 2–5).

**Figure 2.** Evaluation of 22 GSR lines and four control variants under control and heat stress. Data for plant height (**A**), tillers per plant (**B**), grain yield per plant (**C**), and straw yield per plant (**D**) were recorded under both conditions. Tuckey's test was used for statistical differences. Different letters above the column varied significantly at *p* < 0.05.

**Figure 3.** Evaluation of 22 GSR lines and four control types under control and heat stress. Data for harvest index per plant (**A**), thousand grain weight (**B**), and grain length (**C**) were recorded under both conditions. Tuckey's test was used for statistical differences. Different letters above the column varied significantly at *p* < 0.05. (**D**) Distribution of heat susceptibility index for grain yield.

**Figure 4.** Pollen fertility test in 22 GSR lines and four control variants of rice. Viable pollens were stained deep brown color, while the sterile pollens were slightly or not stained (bars = 100 μm).



\* *p* < 0.05, \*\* *p* < 0.01, \*\*\* *p* < 0.001, and ns = non-significant. SOV = Source of variation, DF = Degree of freedom, G = Genotype, Rep = Replication, T = Treatment, G × T = Genotype × Treatment interactions, H<sup>2</sup> = Heritability, PH = Plant height (cm), TPP = Tillers per plant, GY = Grain yield per plant (g), SY = Straw yield per plant (g), HI = Harvest index, GW = 1000-Grain weight (g), GL = Grain length (mm), NDVI = Normalized difference vegetative index, PFP = Pollen fertility percentage.

**Figure 5.** Effect of heat stress on pollen fertility (**A**), NDVI (normalized difference vegetative index, **B**), and cell membrane stability (CMS, **C**). Data was mean ± SE of three replicates. Tuckey's test was used for statistical differences. Different letters above the column varied significantly at *p* < 0.05.
