Genetic studies on agro-morphology, quality traits, blast resistance and QTL detection for iron and zinc contents in rice (Oryza sativa L.)
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Date
2017-08
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G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand)
Abstract
The present investigation entitled “Genetic studies on agro-morphology, quality traits, blast resistance and QTL detection for Iron and Zinc contents in rice (Oryza sativa L.)” was carried out during kharif, 2014-15 and 2015-16 at G.B. Pant University of Agriculture & Technology, Pantnagar, Uttarakhand and V.P.K.A.S. Almora, Hawalbag, during kharif, 2015-16. The research material consisted of twenty-nine lines of rice genotypes, F2 segregating population of cross Basmati-370 and Taraori Basmati and two cross were taken for inheritance study of rice leaf blast at field and molecular level. Analysis of variance explained highly significant differences among the rice genotypes for all the ten yield and yield component traits. High heritability coupled with high genetic advance and high to moderate PCV and GCV were observed for number of effective tillers per plant, flag leaf area, grain yield per plant and test weight. At phenotypic and genotypic level grain yield per plant showed the significant positive correlation with number of effective tillers per plant and test weight. The path coefficient analysis revealed at the phenotypic level, number of effective tillers per plant had a highest positive direct effect on grain yield per plant followed by flag leaf area, days to maturity, panicle length and leaf length.
Analysis of variance exhibited highly significant and usable variability among the genotypes for all the quality parameters. High to moderate values of PCV and GCV, high heritability pair with high genetic advance were observed for most of the characters, i.e. cooked kernel length, kernel length breadth ratio, cooked kernel length breadth ratio, milling recovery (%) and head rice recovery (%). Dunken Multiple Range Test (DMRT) revealed the presence of significant difference among the rice genotypes for micronutrient concentrations. In brown rice iron concentration ranged from 23.13 - 53.38 mg kg-1 whereas, zinc concentration ranged from 23.27 - 54.49 mg kg-1. In white rice iron concentration ranged from 9.04 - 25.11 mg kg-1 whereas, zinc concentration varied from 9.04-25.25 mg kg-1. Per cent loss for the iron and zinc concentration in rice grain ranged from 23.67 - 80.43 and 19.35 - 71.66 per cent respectively.
The loss in micronutrient content after milling changed with the grain type as long slender grain type showed more percent loss for micronutrient the short bold grain type.
SSR markers were used to estimate molecular diversity among the genotypes for the micronutrients content. Using eighteen SSR markers 53 alleles were detected among the rice genotypes range of 80 to 1000 bp with five rare alleles. PIC value ranged from RM 340 (0.339) to OsNRAMP 7 (0.803) similarity coefficients between the pair of genotypes varied from maximum of 0.67 to a minimum of 0.04. Based on Jaccards similarity coefficients, UPGMA ordered the twenty-nine rice genotypes in to four clusters. Cluster III and IV had a similarity coefficient of 0.31 and genotypes found in those clusters were show diversity.
In F2 population, Basmati-370 and Taraori Basmati were taken as parents and showed a range of grain iron and zinc content in brown rice 34.22 ppm, 43.31 ppm and 53.38 ppm, 54.49 ppm, respectively. The F2 population was varied for iron content from 9.56 to 80.73 ppm whereas, for zinc content from 5.37 to 53.96 ppm. Seven polymorphic primers subjected to single marker analysis and discovered 14 QTLs associated with morphological traits. RM 21 marker located on chromosome no. 11, explained the maximum phenotypic variation for zinc content which was 17.87 percent and for iron content it showed 6.02 percent phenotypic variation. Inheritance study for rice leaf blast the cross PB-1 X IR-64 only show the genotypic as well as phenotypic ratio in 3:1 for susceptible to resistant reaction.
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