International Journal of Applied Research
Vol. 2, Issue 7, Part A (2016)
Epistasis is an important genetic basis of grain size in pearl millet
V Vengadessan and MT Vinayan
Epistatic interactions contribute significantly to the genetic basis of variation present in grain size of pearl millet. This is demonstrated with the classical genetic experiment involving generation means and triple test cross (TTC) analyses and also through the QTL analysis involving F2:3 progenies of a single cross between inbreeds of contrasting grain sizes. The data on grain size were obtained from six basic generations (P1, P2, F1, F2, BC1 and BC2), 180 TTC families and 188 F2:3 progenies for generation means, TTC and QTL analysis, respectively. The results of classical genetic analysis revealed that a large part of the genetic variation of grain size was under the epistasis control, particularly interactions of the dominance x dominance and dominance x additive, which were largely significant in both the generation means and TTC analysis. The presence of epistasis must imply multiple QTL for grain size. The QTL analysis located five significant main effects QTLs in the regions of chromosome 1, 3, 5, 6 and 7. Furthermore, significant epistatic effects, additive x dominance and dominance x dominance were also observed among the detected QTLs. The results of QTL analysis are consistent with the classical genetic approaches for the nature of epistatic interactions. The presence of epistatic interactions through classical genetic analysis and among the detected QTLs for grain size suggested that the marginal effects could be severally biased. Epistasis therefore needs to be considered, as the nature of interactions can guide the researcher to the selection of appropriate genetic background to obtain maximal gain.
How to cite this article:
V Vengadessan and MT Vinayan. Epistasis is an important genetic basis of grain size in pearl millet. International Journal of Applied Research. 2016; 2(7): 16-24.