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Subject: Agricultural Biotechnology × Author: DAS, KINGSUK × Start date: 2019 × Thesis Type: M.Sc ×
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    ThesisItemOpen Access
    GENOMIC STUDIES FOR AROMA IN JOHA RICE OF ASSAM
    (AAU, Jorhat, 2020-09) DAS, KINGSUK; Baruah, A. R.
    The badh2 locus for aroma in Basmati and Jasmine rice has been extensively studied and the present study was intended to target the functional marker for aroma, badh2 to determine the fidelity of the marker and validate the same to group the joha rice of Assam in particular. A total of 90 small-grained rice cultivars including 60 joha rice was included in the study. All the fieldwork and laboratory work were carried out at the ICR farm and in the Department of Agricultural Biotechnology, AAU, respectively. The study revealed that the majority of the joha cultivars (44) and 22 non-joha types including four chakhow, three jeera rice were detected with the aroma allele for badh2. The cultivars could be grouped into three based on the results of marker profile using the primer pairs for badh2 (Group I: cultivars possessing aromatic badh2 allele, Group II: cultivars with non-aromatic badh2 allele and Group III: Heterozygous for badh2). The cultivars were genotyped further using 23 markers linked to aroma (other than badh2), and those loci (mostly minor) were mapped previously flanking the regions of badh2. The markers used in the study detected 43.47% polymorphism, and only those polymorphic marker loci were analysed for allelic composition among the three groups of cultivars. The number of marker alleles ranged from 2-4 with a mean of 3.11. Except for 10L03, RM223, RM282, the rest of the markers showed higher homozygosity, indicating that high resolution of allelic difference among the groups of cultivars would be possible. The cultivars of Group I, i.e., with aromatic badh2 are distinctly unique from the other two groups, suggesting the allelic composition within the Group I was intact (share the same allele most of the time) and could be different from Groups II and III at many times. The Group I was detected a significantly higher number of expected alleles as compared to the other two groups except for RM 282, indicating the determinant of aroma might be governed by badh2 along with some other minor loci in the case of Group I. The present study could throw some light that in joha rice cultivars, the involvement of badh2 along with few other minor loci is mainly responsible for the aroma.