Rai, MayankLap, Bharati2023-02-082023-02-082021-12https://krishikosh.egranth.ac.in/handle/1/5810193446The North-Eastern Region (NER) of India is home to various unique landraces with coloured, nutritionally rich aromatic grains that have high economic value in national and international markets. However, many of such landraces are low yielding and suffer from susceptibility to diseases like blast. The present study was undertaken involving three important landraces of Chakhao Poireiton (purple pericarp), Mang Meikri (light brown pericarp) and Kala Joha to understand the inheritance of pericarp colour and aroma using different biparental populations (F2, F2:F3, RILs) derived from crosses between these landraces and elite high yielding varieties. The presence of the fragrance gene badh2 was found in all the three aromatic cultivars of Chakhao Poireiton, Kala Joha and Pusa Basmati 1121. Selective crosses were made between the eight parental genotypes, and three populations (ULRC34, ULRC43 and ULRC45) were targeted for further detailed analysis. The reported gene for light brown pericarp Rc was observed in two cultivars Shahsarang and Mang Meikri. In contrast, the Kala4 allele for purple colour was present in Chakhao Poirieton, Kala Joha and Mang Meikri irrespective of their pericarp colour. The Kala4 gene was highly associated with the purple pericarp in all three populations. However, in the segregating population ULRC43, white pericarp was observed in the presence of the Kala4 allele suggesting that the presence of Kala4 does not always lead to purple pigmentation in the pericarp, as indicated by the colour white and light brown in Kala Joha and Mang Meikri that carry the Kala4 allele. This indicates the presence of novel loci that may be responsible for purple pericarp independent of Kala4. Segregation distortion was observed in the cross ULRC43, where Rc locus was also segregating along with Kala4 and Kala3 genes. The Rc allele was only present in seven individuals out of 183 F2:F3. Data on blast were recorded for three consecutive years in RILs of ULRC34 having contrasting parents. Nineteen candidate genes and sixty-four random markers, including SNPs, were scored in the RIL population. Markers PB3810, PR5-2, snpOS0024, snpOS0296, snpOS0305, snpOS0317 on chromosomes 11, 5, 1, 4 and 12 respectively were found to be associated with leaf blast resistance, and HvSSR02- 33, HvSSR07-44 on chromosome numbers 2 and 7, respectively, were associated with neck blast resistance at 1% level of significance. In the three populations studied, seed anthocyanin pigmentation was negatively correlated with grain yield. However, certain high yielding progenies with desired grain characteristics were selected that yielded higher than the parent landraces in early segregating generations of different crosses. Per cent superiority of selected lines over their parent landrace ranged from -57.92 to +203.49%. Anthocyanin estimation was also done for selected progenies with coloured pericarp. It ranged from 0.0001 to 3.324 μg/100mg, suggesting nine lines, i.e., ULRC46-326(4), ULRC43-67(2), ULRC43-546(1), ULRC48-379(2), ULRC43-316(1), ULRC34-202(2)-1, ULRC34-242(4)-2, ULRC34-87(3)-5, ULRC34-195(4)-2 having aroma, high anthocyanin content, blast resistance and better yield than the parents.EnglishRiceGenetic techniquesThesis