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Subject: Genetics and Plant Breeding × Author: Aparna × End date: 2021 × Start date: 2021 × Thesis Type: Ph.D ×
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    ThesisItemOpen Access
    Classical and molecular approaches of brown planthopper resistance and quality traits in rice (Oryza sativa L.)
    (G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand), 2021-03) Aparna; Indra Deo
    Rice (Oryza sativa L.) is one amongst the foremost cereal crop for over 50 percent of the world’s population. Approximately 52% of world rice yield is destroyed annually due to biotic factors. Insects solely accounts for nearly 21 % of the total loss caused by living organisms. Brown planthopper is a serious threat to rice crop. Most consequential symptoms of brown plant hopper is ‘‘hopperburn’’. Rice displays huge range of genetic variation for agro-morphological and quality traits (including micronutrients). Present investigation entitled “Classical and molecular approaches of brown planthopper resistance and quality traits in rice (Oryza sativa L.)” has been conducted with the objective to study agro-morphological traits, quality traits, marker trait association for brown planthopper resistance and iron and zinc contents in rice. Fifty advanced Basmati breeding lines, popular Basmati, scented and non-Basmati varieties were used for screening against brown planthopper resistance, agro-morphological characterization, estimation of quality traits (including iron and zinc) and molecular characterization. 136 genotypes which include 132 lines of IIRON (International Irrigated Rice Observation Nursery) and 4 local checks were used for agro-morphological characterization using augmented design. All the field experiments were conducted at the Norman E. Borlaug Crop Research Centre of Govind Ballabh Pant University of Agriculture and Technology, Pantnagar, Uttarakhand. Screening of genotypes for BPH resistance was performed at Department of Entomology, GBPUAT, Pantnagar, Uttarakhand. Molecular work and most of the quality works were performed at Cyto-genetics and Molecular Biology Laboratory, Department of Genetics and Plant Breeding, GBPUAT, Pantnagar, Uttarakhand. Phenotypic evaluation of rice genotypes using standard seed box screening technique revealed that only one line RP2068 was resistant to brown planthopper and most of the genotypes exhibited susceptible response. Upon marker trait association analysis for BPH resistance, significant association was observed for markers RM 589 and RM 216. Evaluation of F2 population for BPH resistance yielded 1(resistance):15 (susceptible) ratio. This indicated digenic recessive inheritance of BPH resistance gene in the present investigation. There was significant variation for agro-morphological and quality traits including micronutrients (iron and zinc) in 50 rice genotypes. In present investigation, high heritability coupled with high genetic advance obtained for plant height, days to 50% flowering, leaf length, number of effective tillers, gel consistency, kernel breadth, kernel length breadth ratio and kernel length after cooking. Results revealed the presence of additive genetic variance and hence selection for above mentioned traits may be effective. Upon principal component analysis for nines agro-morphological traits, four principal components were obtained. Initial four principal components described 69.38 % of the total phenotypic variance. In the present experiment, significant difference was obtained for iron and zinc contents in rice genotypes using Duncan multiple range test at 5 % level. Concentration of zinc was found to be higher than iron in rice grain. High correlation was obtained between iron and zinc content in brown rice. It was found that milling depression was more in case of iron as compared to zinc. SSR markers indicated considerable genetic diversity among genotypes studied for iron and zinc contents. Highest PIC value obtained for Os NRAMP 7, OsVIT1 and RM152 markers. SSR marker genotyping classified genotypes into two broad clusters based on Jaccard’s similarity coefficient. Analysis of variance for augmented block design exhibited significant variation for 14 agro-morphological traits for IIRON lines.