Morphological characterization of forage sorghum [Sorghum bicolor (L.) Moench] varieties for DUS testing

Abstract

Twenty six varieties of forage sorghum [Sorghum bicolor (L.) Moench] which included 20 released and notified and 6 indigenous local varieties were characterized using 40 morphological descriptors adopted from the DUS guidelines of PPV and FR Authority and ICAR and subsequently examined for their Distinctiveness, Uniformity and Stability. Among the 26 visually assessed characters 2 characters were monomorphic, 10 characters were dimorphic and 14 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. Combined Over Years Distinctiveness (COY-D) analysis was made on 14 measurable DUS descriptors which revealed distinctiveness for all the 26 varieties. COY-D analysis supported with MJRA analysis revealed that the slope of the MJRA curve and regression probability were too negligible which indicated that all the considered characteristics were independent and their interactions with environment as well as with themselves were negligible in both the years. This indicates the distinctiveness of all the candidate varieties. Combined Over Years Uniformity (COY-U) analysis revealed that all the released and notified varieties were more or less uniform for the 14 measurable characters. However, three local varieties viz., Rampur local, Gwalior local and Rajasthan local were not uniform for 7, 6 and 4 measurable characters respectively emphasizing the need for their further purification to attain a considerable level of homogeneity in their heterogeneous blend. The present experimental material possessed relatively low magnitude of differences between PCV and GCV, high heritability coupled with high to moderate genetic advance for most of the measurable descriptors, thus emphasizing their consistency and stability over the years and their utility in varietal characterization. On the basis of grouping characteristics unique morphological profiles could be established for 9 varieties. When all the 33 morphological descriptors of PPV and FR Authority and 7 morphological descriptors of ICAR were studied distinctiveness could be obtained for two more varieties viz., UPFS 38 and SSG 59-3. Thus out of a total of twenty six varieties unique morphological profiles could be obtained for 11 varieties. However, the rest of 15 varieties remained in groups of two or three varieties. Thus the morphological DUS descriptors could establish distinctiveness of some varieties but varieties showing overlapping of the expression for these characters could not be discriminated hence some other markers/ descriptors could be thought for complementing the morphological DUS descriptors.