Manoj M S

Title : Linkage studies in rice (Oryza Sativa L.)

Abstract:

Rice (Oryza sativa L.) serves as a global staple, sustaining nearly half of the world’s population. Certain rice varieties possess anthocyanin pigmentation, which is highly variable and a distinctive feature of the crop. It confers resistance to UV radiation and elicits responses to biotic and abiotic stresses. With this background, an experiment was conducted during the 2022-2023 at All India Coordinated Rice Improvement Project (Voluntary Centre), Agriculture Research Station (Paddy), Sirsi, University of Agricultural Sciences, Dharwad, to investigate the genetic inheritance and linkage of anthocyanin pigmentation and morphological traits in rice plants. Observations regarding presence or absence of pigmentation were meticulously recorded across various plant regions, including the culm base, leaf sheath, prophyllum, leaf blade, leaf tip, leaf margin, midrib, ligule, auricle, juncture, junctura back, node, internode, panicle base, stigma and apiculus. Additionally, morphological traits like culm angle, flag leaf angle and panicle type were examined across parental, F1, F2 and F3 generations. The F1 plants exhibited purple anthocyanin pigmentation solely in the culm base, leaf sheath and apiculus regions, indicating its dominance. In the F2 generation, 1320 plants exhibited seven different segregation ratios (3:1, 3:13, 3:61, 9:55, 21:43, 27:37 and 39:25) for anthocyanin pigmentation, implying the involvement of one to three genes with varying gene interactions and the same were confirmed by studying the breeding behaviour of 134 F3 families raised from randomly selected F2 plants. Furthermore, a joint segregation analysis was conducted to determine whether the considered genes segregated independently or were linked to other traits. Various traits, including apiculus, node, internode, culm angle, flag leaf angle and panicle type, exhibited non-significant chi-square values, indicating independent assortment. However, the remaining thirteen traits exhibited genetic linkage. Subsequently, linkage studies were conducted using the product ratio method, the relative distances between genes were estimated and expressed as a percentage of recombination. The linkage map revealed two primary linkage groups. The first group encompassed eight genes governing pigmentation, arranged sequentially as Ppr – Ppb – I-Pj – I-Pl_a – Pla – Pjb_a – Plm – I-Pmr_a and tentatively assigned to group II (Sp group). The second group included five genes, Ps – Pcb – Plg_a – Psh – Pau_a in that order and tentatively placed in group III (Ig group).

What will audience learn from your presentation?

• Importance of anthocyanin pigmentation in rice
• Genetic linkage studies
• Linkage mapping for anthocyanin pigmentation in rice
• Helps to identify true hybrids during hybridization

Biography:

Dr. Manoj M. S. studied Genetics and Plant Breeding at the College of Agriculture, University of Agricultural Sciences, Dharwad and graduated as Master of Science in 2019. He received his PhD degree in 2023 at the same institution supervised by Dr P. Surendra. He has published 3 research articles in different journals.