Kumari, VednaTiwari, Sunidhi2024-08-202024-08-202023-08-03A-2019-40-020https://krishikosh.egranth.ac.in/handle/1/5810213392The p esent st entit e “Geneti ana sis o see ie an q a it t aits an mo e a ha a te ization for white rust resistance in Indian Mustard [Brassica juncea L. (Czern. & Coss.)]’’ was a ie o t to congregate information on genetic architecture, combining ability, heterosis and inheritance of white rust resistance. The materials for the investigation comprised of 12 lines, three testers (RCC-4, Donskaja-IV and their F1) and resulting 36 TTC hybrids. These progenies and their parents were grown in randomized complete block design with three replications during rabi 2021-22 at the Experimental Farm of the Department of Genetics and Plant Breeding, CSK HPKV, Palampur (H.P.). Analysis of variance indicated the significance of mean squares due to genotypes for all the traits which revealed the presence of sufficient genetic variability in the existing material. Modified triple test cross analysis exhibited the presence of epistasis for all the traits namely, days to flower initiation, days to 75 per cent maturity, plant height, reproductive phase, number of primary branches per plant, number of secondary branches per plant, siliquae per plant, length of main shoot, siliquae length, seeds per siliqua, 1000-seed weight, seed yield per plant, biological yield per plant and harvest index except for days to 50 per ent owe ing. F the , pa titioning o epistasis e ea e the impo tan e o ‘j ’ t pe o epistasis o a most all the t aits ex ept a s to 50 pe ent owe ing whe eas mean sq a es e to ‘i’ t pe inte a tion we e non significant for most of the traits except number of secondary branches per plant, siliquae per plant, siliqua length, seeds per siliqua, seed yield per plant and biological yield per plant which shows the importance of both ‘i’ t pe an ‘j ’ t pe o epistasis. Re ati e magnit e o a iti e omponent D) was p e ominant o e dominance component (H) for most of the traits except reproductive phase, number of secondary branches per plant, siliquae per plant and biological yield per plant indicating the relative importance of fixable type of gene action in their inheritance. Analysis of variance for line× tester revealed the presence of substantial genetic variability. Analysis of variance for combining ability indicated significant differences among hybrids for all the traits studied. The genotype DRMR 2017 was found to be good general combiner for nine traits followed by RSPR-03 for eight traits and Pusa Mehak for seven traits. Five crosses viz., Pusa Tarak × Donskaja-IV, Kranti × Donskaja-IV, RSPR-03 × Donskaja-IV, DRMR 2017 × RCC-4 and Urvashi × Donskaja-IV exhibited higher per se performance, significant SCA effects and heterobeltiosis for seed yield per plant. Two crosses namely, Urvashi × Donskaja-IV and Pusa Tarak × F1 showe ow g osino ate ontent ˂30 µmole per gram of defatted seed meal) and only one genotype viz., Pusa Karishma showed low erucic acid ˂ 2 pe ent). To study the inheritance of white rust resistance, two crosses (RCC-4 × Donskaja-IV and RCC-4 × Heera) were evaluated. In cross RCC-4 × Donskaja-IV, dominant epistasis (12:3:1) was observed while in cross RCC-4 × Heera, complementary epistasis (9:7) was observed. Molecular characterization revealed that intron polymorphic (IP) markers viz., At5g41560 and At2g36360 were highly linked to white rust resistance loci AcB1-A4.1 and AcB1- A5.1 and could be helpful in marker assisted selection for white rust resistance in Indian mustard.EnglishThesis