Assessment of distinctiveness, uniformity and stability of indigenous aromatic rice (Oryza sativa) varieties based on morphological descriptors

Abstract

Twenty indigenous aromatic rice varieties were characterized using morphological descriptors adopted from the DUS guidelines of PPV and FR Authority and subsequently examined for their distinctiveness, uniformity and stability. Among the 46 visually assessed characters, 24 characters were monomorphic, 17 characters were dimorphic and 5 characters were polymorphic indicating their potential for varietal characterization and distinctiveness. No intra-varietal variation was observed for any of the visual characteristics and expression of characters in different varieties remained same for the two consecutive years confirming the uniformity and stability of the varieties for visual characteristics. Combined over years distinctiveness (COY-D) analysis was made on 14 measurable DUS descriptors which revealed distinctiveness for all except Tilakchandan varieties 3047 and 3048 with respect to each other only. COY-D analysis was complemented with Modified Joint Regression Analysis (MJRA). The slope of the MJRA curves in both the years and regression coefficient indicated that all the considered characters were not completely independent and they are interacting with each other as well as with environment. Combined Over Years Uniformity (COY-U) analysis for five of the measurable characteristics revealed that nine out of 20 varieties were completely uniform for the characters under study. However, the other 11 varieties were non-uniform for one or two characters emphasizing the need for their further purification to attain a considerable level of homogeneity in their heterogeneous blend. On the basis of grouping characteristics unique morphological profiles could be established for seven varieties only. When all the 60 morphological descriptors were studied no further distinctive profile could be obtained for any other variety. Thus the morphological DUS descriptors could establish distinctiveness of some varieties but varieties of similar background could not be discriminated hence some other markers/ descriptors could be thought for complementing the morphological DUS descriptors for establishing distinctiveness.