Indian Society of Genetics & Plant Breeding

Stay green behaviour of a novel mutant, PSG16 shows complex inheritance and functional relations with grain yield in rice

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To ensure food security for the future, contemporary rice breeding has to harness novel secondary traits linked to higher productivity.
Functional staygreen (SG) is one such trait that has shown promise by delaying senescence while improving crop productivity. Pusastay-green 16 (PSG 16) is a novel SG mutant that appeared in a breeding population that showed true to type breeding in subsequent
generations and higher grain yield. Study of the inheritance pattern of the SG behavior in PSG16, by crossing with two non-SG parents
Pusa 677 and Pusa 44 indicated a major gene inheritance in the F
2 generation. The trait was found associated with the measure of total
chlorophyll content (TCC) at the physiological maturity stage. The relationship of TCC to other agronomic traits, in the segregating
populations of the cross, from F
2-F5, showed a consistent association with grain yield, suggesting the functional property of the SG trait.
However, TCC showed a quantitative inheritance pattern. Additional investigations on the inheritance pattern and gene actions for the
TCC revealed signifcant additive and dominant gene actions. The dominance superseded the additive component on an individual
gene basis, thereby signifying the class variation observed under the goodness of ft test. However, a large interaction component with
additive x additive gene action could be identifed in trait expression. Therefore, the inheritance of SG trait was complex and deviated
from the simple additive dominance pattern. A careful breeding procedure involving intermating, sib-mating and recurrent selection
may be needed to utilize the trait in crop improvement. The causative loci need to be mapped for further understanding of the SG
behavior of PSG16, along with in-depth physiological characterization for the functionality of the trait.

Keywords: Epistasis, Gene action, Grain yield, Inheritance, Stay green

Info

Year: 2021
Volume: 81
Issue: 4
Article DOI: 10.31742/IJGPB.81.4.1
Print ISSN: 0019-5200
Online ISSN: 0975-6906

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