B., FAKRUDINP., SHREEDHARAH.B., LINGAIAHV., DEVAPPAG. K., HALESHG.K., RAMEGOWDA2021-09-222021-09-222018-09UHS15PGM643https://krishikosh.egranth.ac.in/handle/1/5810176058Combining ability and heterosis effects in Line × Tester derived 64 F1 hybrids involving eight each ToLCV susceptible and resistant genotypes revealed similar effects due to mating design at Hogalagere (65.97%) and Bengaluru (68.76 %). Reaction of F1 hybrids to ToLCV incidence was comparable at both locations: in all 8-28 immune, 26-32 resistant, 10-23 moderately resistant and 1-10 moderately susceptible F1 hybrids were recorded at 60 days after transplanting (DAT). Anagha × COHBT-75, PKM-1 × COHBT-75, COHBT-27 × COHBT-75, COHBT-33 × COHBT-75, COHBT-33 × COHBT-36, COHBT-33 × COHBT-75, COHBT-33 × H-24, COHBT-127 × COHBT-75 and COHBT-132 × COHBT-36 crosses found consistently resistant to ToLCD. Highest fruit yield per plant (3.06 kg) was recorded by COHBT-33 × COHBT-75 followed by DMT-2 × COHBT-75 (2.23 kg), COHBT-64 × COHBT-134 (2.04 kg) and Anagha × COHBT-134 (2.01kg). DMT-2, COHBT-27 and PKM-1 were the best lines and COHBT-36, COHBT-75, COHBT-134 and H-24 best testers for ToLCV resistance. RdRP being 29272 bp comprising of three genes viz., Solyc06g051170 (11848 bp) Solyc06g051180 (608bp) and Solyc06g051190 (4243bp) was allele mined in 16 genotypes. A total of 50 nucleotide changes across the genotypes was recorded; 18 in Solyc06g051170; 16 in Solyc06g051180; 16 in Solyc06g051190. In Solyc06g051180 a nucleotide change at 125th position from Thymine to Guanine in all resistant genotypes changed Arginine (R) to Threonine (T) in the predicted protein. A set of 15 TF genes of WRKY, AP2/ERF and WIRLY families revealed differential expression patters in response to ToLCV incidence.EnglishThesis