Estimation of Combining Ability, Gene Action and Components of Genetic Variation in Forage Sorghum [Sorghum bicolor (L.)]

Aims: To Study the combining ability effects and evaluate the genetics of the parents for fodder yield and its component traits in sorghum.

Study Design: Randomized block design.

Place and Duration of Study: The seeds of F1 hybrids were produced during summer 2022 at Center for Millets Research, S. D. Agricultural University, Deesa.

Methodology: Six parental genotypes were used in the experiment, which produced 15 half-diallel crosses in sorghum.

Results: The analysis of variance for combining-ability (CA) studies revealed that mean sum of squares due to general combining ability (GCA) were important for most of the characters except the leaf length of blade. Based on the gca effect, the parents CSV 46, IS 3338 and Malwan were good general combiners for green and dry fodder yield per plant. The unit slope of regression line and non- significant t2 value asserted the validity of the additive-dominance model for total plant height, number of leaf per plant, stem diameter, leaf length of blade, leaf width of blade, dry fodder yield per plant and crude protein content in dry fodder. The value of H1 was superior to H2 for most of the characters representing that gene distribution frequency in the parent genotypes was asymmetry and that was supported by the ratio of H2/4H1 (i.e., less than 0.25). The KD/KR components value was greater than one among most of the traits except for number of leaf per plant and crude protein content in dry fodder showed that parents had more dominant genes compared to recessive genes frequency.

Conclusion: The ratio of σ2gca/σ2sca being more than unity, which suggested greater role
of additive genetic variance in the inheritance of these traits. The genetic components
of variance and graphical analysis revealed that different type of gene action were involved for forage yield and components traits in sorghum.