Background: Horse gram is an underutilized legume but possesses multi-utilities. The narrower genetic base warrants targeted crop improvement attempts. Induced mutagenesis evolved a few promising mutants for yield whose breeding potency through multiple environment experiments (MEEs) was assessed. 
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Methods: The stability of the high-yielding mutants was assessed through MEEs (six environments in two cropping years) using multiple trait-based selection indices (SIs). The coincidence index was utilized to identify the&nbsp;most common stable genotypes identified by SIs. The effectiveness of the SIs was assessed using the selection differential (SDs). 
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Result: The multi trait-based SIs namely MGIDI, FAI-BLUP and SH index facilitated the selection of superior and stable horse gram mutant genotypes. The results of both preliminary (PT) and confirmatory trials (CT) were analysed using the&nbsp;coincidence index and identified the most common stable mutant genotypes G1, G3, G27 and G22. Based on the SDs for yield-related traits, it is inferred that the SI MGIDI can be relied upon to enhance the genetic gain for yield-associated traits improvement. The SIs, FAI-BLUP and the SH shall be utilized to improve growth-related traits in horse gram.&nbsp;

Identification and Validation of Stable Horse Gram [Macrotyloma uniflorum (Lam.) Verdc.] Genotypes using Multi-trait based Selection Indices in Multi-environment Experiments