Reclassifying Indian Soybean [Glycine max (L.) Merrill.] Varieties on the Basis of New and Improved DUS Characteristics and Categories

Soybean [Glycine max (L.) Merrill.] stands as the leading oilseed crop globally and in India, valued for its dual role as a vegetable oil and protein source. India has released and notified 176 soybean varieties since the 1970s. This evolution aligns with intellectual property rights, particularly the TRIPS agreement, prompting India to establish the Protection of Plant Varieties and Farmers’ Rights Act in 2001, followed by guidelines for variety protection, including Distinctiveness, Uniformity and Stability (DUS) testing for soybean initiated in 2009. As soybean cultivation in India progresses from limited early introductions to a diverse range of genetically enhanced varieties, there remains potential for expanding the morphological characteristics to ensure better differentiation and distinctiveness among varieties.

The ICAR-Indian Institute of Soybean Research, Indore, studied 127 soybean varieties released for commercial cultivation in India between 2016 and 2022 during each kharif (rainy) season. A total of 127 released and notified soybean varieties were observed for seedling hypocotyl pigmentation, leaf shape, leaf size, inflorescence pattern, leaf blistering, pod color, seed color, seed hilum color, pod pubescence, by randomly selecting a group of 20 plants from each plot for the respective varieties following PPV and FRA guidelines.

Our findings revealed discrepancies in trait identification among several varieties based on DUS guidelines. We identified opportunities to expand these guidelines by incorporating additional traits like categorizing hypocotyl anthocyanin pigmentation as high, medium, low, or absent; classifying leaf shapes into lanceolate, triangular, pointed ovate and round ovate and assessing leaf size and blistering. Inflorescence patterns, seed colour, hilum colour and pod colour should also be better defined. This finding underscores the importance of re-evaluating existing assessment criteria to include such traits, which could enhance the understanding and classification of soybean varieties.