Internode elongation pattern and differential response of rice genotypes to varying levels of flood water

Abstract

Rice plants are damaged during floods by complete or partial submergence. The pattern of expression of rice plant varies with different flood regimes. Accordingly, the morphological and physiological responses of rice genotypes were studied in field and pot experiments under different flood regimes. Wide genetic base lines of Oryza sativa and sub 1 introgressed submergence tolerant were compared in field experiments using principle component analysis. Further, based on internode elongation pattern, two genotypes – Bodikaburi and Pokkali – were selected for a pot experiment to find more on elongation pattern of internodes under different flood regimes. Short-term submergence in minimal water, elongation of blade, sheath, leaf area, DW, number of nodes in primary stem and survival present showed strong positive relationship with shoot length. Number of tillers, leaf area and DW were more affected and decreased during submergence than its non-submergence counterpart. Under different flooding regimes, cvv Bodikaburi and Pokkali exhibited different behaviour in the elongation pattern of the shoot. Partial submergence accelerated elongation of all internodes whereas complete submergence accelerated the top internode. Enhancement of shoot elongation during submergence in water is an escape strategy adopted by rice to resume aerobic metabolism and to improve carbon fixation. This escape strategy varies among genotypes with respect to different flooding regimes. Therefore, breeders should be aware of breeding of rice plants with suitable architecture for different flood- prone environments.

Short-Term Complete Submergence of Rice at the Tillering Stage Increases Yield

“…At the different submergence depths, 1 d of submergence decreased or significantly decreased the height of the plant, and 5 d of submergence increased or significantly increased the height of the plant; 3 d of submergence did not cause significant changes. Our results are consistent with those reported in the literature [ 3 , 5 , 7 , 36 ] and may indicate that the increase in plant height becomes more noticeable with prolonged submergence. The underlying reason is presumably as follows.…”

“…The findings of this study show that 1 d of complete submergence significantly increased the yield of rice, which contradicts the assumption that a short-term waterlogging disaster is detrimental to rice growth [ 3 – 9 ]. This discrepancy may be partially due to the differences between this study and previous studies in terms of the duration of rice submergence, submergence temperature, submergence stage, and rice cultivar selected.…”

Population Structure, Diversity and Trait Association Analysis in Rice (Oryza sativa L.) Germplasm for Early Seedling Vigor (ESV) Using Trait Linked SSR Markers

“…An initial descriptive statistics, including mean, standard deviation, minimum and maximum values, coefficient of variation (%), skewness, kurtosis, and distribution pattern was performed by box plot technique. PCA was performed to estimate Euclidean distance between two genotypes in the multivariate space and adaptation of genotypes to specific environment [ 6 – 7 ]. These analyses were performed using the Windostat 7.5 software (Indostat Services, Hyderabad, India.).…”

Non-destructive phenotyping for early seedling vigor in direct-seeded rice

“…Principal component analysis (PCA) was performed with 29 traits at 14 DAS and 44 traits at 28 DAS to estimate the variability among genotypes and traits. Biplot figures explain the variances of the variables and correlation between the variables through vectors and similarity between genotypes in the multivariate space based on the nature of growth rate [ 41 , 42 ]. These analyses were performed using Windostat 7.5 software.…”