Singh, N. K.Varalakshmi S.2023-03-142023-03-142022-12https://krishikosh.egranth.ac.in/handle/1/5810195207The main objectives of the investigation were to identify the genomic regions for BLSB resistance and other traits, to determine protein content and its association with SSR markers in teosinte-derived lines, maize and its wild relatives. The various experiments were conducted from 2019-20 to 2021-22for generation and field evaluation, and laboratory analysis of experimental materials. The characterization of teosinte derived 181 BC1F2 lines showed significant variation for all morphological traits and BLSB disease incidence. Of the 181 plants, 23, 53, 65 and 40 plants were grouped under resistance, moderately resistance, moderately susceptible and susceptible categories based on PDI score. The plants TM-1, TM-11, TM-12, TM-21, TM-28, TM-29, TM-54, TM-55, TM- 67, TM-77, TM-78, TM-85, TM-88, TM-94, TM-96, TM-101, TM-103, TM-113, TM-144, TM-152, TM-159, TM-161, and TM-167 were categorized under resistance group with PDI score of ≤ 33.33.The BC1F2 plants showed significant variability for days to anthesis, days to silking, anthesis - silking interval, flag leaf length, flag leaf width, flag leaf angle, plant height, node bearing primary cob and number of ears per plant. A total of 41QTLs were identified for BLSB resistance and 8 morphological traits based on single marker analysis. Two QTLs for BLSB resistance were mapped on chromosome 3 and 10 associated with markers umc2255 and bnlg1518 and having phenotypic variation of 3.79 and 2.22 per cent, respectively. Of the remaining 39 QTLs, 3 QTLs were for days to anthesis, 2 for days to silking, 5 for anthesis -silking interval, 4 for flag leaf length, 6 for flag leaf width, 4 for plant height, 6 for node bearing primary ear and 9 QTLs were for number of ears per plant. Using inclusive composite interval mapping method, a total of 12 QTLs were identified for BLSB resistance and 7 morphological traits and no QTL identified for node bearing primary ear trait. The QTLs qtlBLSB4.1 and qtlBLSB9.1 were detected on 4 and 9 chromosomes for BLSB resistance determining phenotypic variation of 2.08 and 4.63 per cent, respectively. The QTLs qtlDTA 8.1, qtlDTS7.1, qtlASI4.1, qtlFLL4.1, qtlFLL 4.2, qtlFLW8.1, qtlFLW10.1, qtlFLW10.2, qtlPH 4.1 and QtlEPP3.1 were mapped for various morphological traits across 3, 4, 7, 8 and 10 chromosomes. Highly significant differences for protein content were observed among 126 BC1F2:3 lines which varied from 9.53 to 16.49 per cent for MP51 and MP6 lines, respectively. Four lines (MP6, MP20, MP36, and MP97) had protein content in the range of 16.07- 16.49 per cent. All the BC1F2:3 lines possessed protein content higher than the maize parent CML-451 but lower than the teosinte. Analysis of protein content in 28 accessions of maize, its wild relatives indicates significant variations. Teosinte accessions possessed 2-3 times higher protein than maize lines, Z. mays subsp. mexicana, occupied top position with (26.29 per cent protein) of the 28 accessions. Five markers umc1294, umc1171, phi091, umc2182 and bnlg292 showed significant association with protein content. The investigation indicates great significance of teosinte for the diversification as well as improvement of maize for resistance to BLSB and kernel protein content. Teosinte may also be prospected for improvement of other traits in maize.EnglishThesis