Establishing Distinctiveness among rice (Oryza sativa L.) varieties based on DUS descriptors.

Abstract

Sixty one extant varieties of rice (Oryza sativa L.) belonging to non-basmati and basmati group were characterized based on fifty-five morphological descriptors at different stages of plant growth. One of the major objective of cultivar characterization is to separate the varieties in to groups and then to identify them individually. To achieve the same, the varieties of the present study were singled out using a combination of grouping characters and essential characters as listed in DUS guidelines. Out of fifty five morphological descriptors studied, six characteristics were found monomorphic, nine were dimorphic and rest forty characteristics were found polymorphic in state of expression. Further the cultivars in the present study showed overlapping of descriptor expression which indicates insufficiency of morphological descriptors for assessment of distinctiveness or non-obviousness. The assessment of descriptor utility revealed that for traits involving anthocyanin coloration and pubescence, the state of expression needs to be modified from the existing one to only presence or absence of these traits.