Gene action studies were conducted using Triple Test Cross (TTC) analysis with the objective of determining the nature and magnitude of gene action for various horticultural traits under different environmental conditions. The ultimate goal was to enhance productivity in garden pea through suitable breeding strategies. Seventy-eight TTC progenies were developed by mating 26 lines (individual F₂ plant progenies from the cross between Palam Sumool × Palam Priya) with three testers—namely, the two parents (L₁ and L₂) and their single-cross F₁ hybrid (L₃). These were evaluated to detect epistasis and gene action across variable environments. Epistasis was detected for most traits, with a predominance of j + l type interactions. Traits such as pod length, seeds per pod, plant height, and pod yield per plant showed isodirectional dominance effects with decreasing magnitude, suggesting the potential utility of dominance effects in breeding. The presence of significant additive gene action for several traits, including pod yield per plant, indicates that early-generation selection could be effective for their improvement. However, the simultaneous expression of j + l type epistasis suggests that heterosis breeding may also have value. Despite this, exploiting hybrid vigor in pea is challenging due to its autogamous (self-pollinating) nature and the lack of genetic or cytoplasmic male sterility systems. Hence, alternative breeding strategies such as diallel selective mating, biparental mating, or recurrent selection followed by pedigree breeding are recommended. Additionally, delayed selection for pod yield and related traits in later generations could allow the exploitation of additive × additive epistatic effects more effectively

Pisum sativum L., triple test cross, gene action, epistasis, methodology

In pea breeding, the primary objective is to develop pure lines that can fix additive × additive (i-type) epistasis, which contributes to the superiority of elite lines (Goldringer et al., 1997). To achieve this, diallel selective mating, biparental mating, or recurrent selection followed by the pedigree method of selection is recommended. Alternatively, delaying selection until later generations of inbreeding (F5 or F6) for traits such as pod yield is advised, as it allows the beneficial effects of additive × additive epistasis to be fully exploited once homozygosity is established (Farshadfar et al., 2008)

Niju Rana, Akhilesh Sharma, Dharminder Kumar and Sandeep Kumar (2025). Detection of Epistasis for Yield and its Contributing Traits in Garden Pea under Mountain Himalayan Region. Biological Forum, 17(6): 102-108