PHOTO-THERMAL RESPONSE SPECIFIC CHARACTERIZATION AND MOLECULAR DIVERSITY ASSESSMENT OF RICE GENOTYPES
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Date
2022
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DRPCAU, PUSA
Abstract
The current study used 32 rice genotypes, including the check, Rajendra Shweta in a Randomized Block Design (RBD) with three replications at the Dr. Rajendra Prasad Central Agricultural University's rice research farm in Pusa, Bihar, during Kharif 2021 in order to characterise each genotype's unique photo-thermal response and evaluate its molecular diversity. 16 putative traits, including agro-meteorological indices and morphological traits were observed, including “Days to 50% Flowering” (DFF), “Days to Physiological Maturity” (DPM), “Plant Height” (PH), “Panicle Length” (PL), “number of Tillers Per Plant” (TPP), “number of Panicles Per Plant” (PPP), “Spikelet Fertility” (SF), “1000-Grain Weight” (TGW), “Growing Degree Days” (GDD), “Photo-Thermal Unit” (PTU), “Helio-Thermal Unit” (HTU), “Photo-Thermal Index” (PTI), “Heat Use Efficiency” (HUE), “Relative Water Content” (RWC), “Critical Temperature for reproductive stage” (CT), and “Grain Yield Per Plant” (GY/P).
The results of the variance analysis of 32 rice genotype revealed that there were significant differences among the genotypes for each of the 16 variables from the variability experiments. While the TGW, TPP, and RWC all showed moderate GCV (Genotypic Coefficients of Variation) and PCV (Phenotypic Coefficients of
Variation) values, high estimates of GCV and PCV were found for characteristics, GY/P, and HUE. HUE, RWC, TPP, TGW, and GY/P all showed high heritability in the current set of materials, which indicates a majority of additive gene impact and will aid selection in early segregating generations. DFF, DPM, PH, PL, TPP, SF, HUE, and RWC are the traits having positively significant correlation of yield and showing positive effect directly at the level of phenotype, which indicates the advantage of these characters for future improvement.
Path analysis shows that traits like DFF, PH, PL, TPP, HUE and RWC had a direct as well as an indirect positive effect on the production of grain at phenotypic and genotypic level.
Using Tocher's clustering method, 32 genotypes of rice were divided into 8 clusters. Cluster I and Cluster II had 14 and 12 genotype respectively, and Clusters VIII, VII, VI, V, IV, and II were monogenotypic. Between VI and VIII, there was the most inter-cluster and between III and IV, the least. Cluster I and II had the longest distance of intra-cluster. Since the majority of the yield-attributing characteristics exhibited greater mean performance in Cluster IV, choosing parents from this cluster would be beneficial. The genotypes RAU 731-21-201, RAU 1407-13-3, and RAU 631-9-10 appeared to be outstanding performers on the basis of all the results of significant criteria, which includes the indices of agro-meteorology under consideration.
Ten microsatellite-based SSR primers that were directed at the rice genome's chromosomes were used to perform an amplification reaction. All of the primer pair combinations resulted in successful amplification. Using the ten primer pairs, 3 unique alleles and 48 shared variants were obtained. There were two shared alleles per locus in RM 3825 and seven shared alleles per locus in RM 15780 and RM 15791. Similar to RM 28130, RM 3825, and RM 15780, these loci only have one unique allele per locus. The examined rice genotypes were divided into seven clusters using a cluster analysis on the basis of similarity index of simple matching.
The pair-wise comparison of entries revealed that RAU 724-48-3 and RAU 425-10, RAU 1415-9-5-7 and RAU 1397-3 had the highest similarity coefficients, while RAU 425-10 and RAU 1487-1-1 had the lowest similarity coefficients.