GGE biplot technique to delineate genotype × environment interactions to identify the stable resistance sources in the lentil—Stemphylium blight pathosystem

Stemphylium blight (SB) is one of the most important biotic stresses of lentil, occuring in almost all major lentil-growing nations. Among 150 species recorded, Stemphylium botryosum (Wallr.) is responsible for inciting SB in lentil. It has a wide host range and perpetuate in the seeds, crop debris and secondary spread occurs through air-borne conidia. The most vulnerable stage of infection is flowering to early pod setting, so, confers a serious threat to lentil production. Environment plays pivotal role in host–pathogen dynamics and also interfere in disease management. This study involves deciphering genotype × environment interactions by utilising GGE biplot to unveil and validate durable resistant genotypes and their performance over three different locations. Primarily, from 70 lentil genotypes, 23 promising genotypes were selected based on their disease reaction (< 30%) against SB and evaluated further across the three locations for two consecutive years. The test result from GGE biplot analysis revealed that genotype exerted higher proportion of variation in SB reaction than environment. Result confirmed the presence of inconsistent genotypic response over locations and years. Selected locations grouped into three environment clusters suggesting the existence of cross over interaction with in the genotypes. Integration of GGE biplot and BLUP analysis identified G-3 (ILL10838/ILWL11/X2016S) as the “ideal” genotype whereas, G-7 (8114/10956/16–1) and G-5 (LIRL22-107/LIRL21-50–1-1–1) as “desirable” genotypes considering their static response against SB over the environment. Genotypes detected through this study could be recommended for their future deployment in lentil resistance breeding programme.