Study of variability in seed morphology, screening of seed borne fungi and uses of rarely cultivated indigenous rice landraces (Oryza sativa L.) of Kerala, India

Conservation is the key to sustainability. Kerala is known to be a host to number of traditional rice varieties, which are dying at a rapid pace. The first and foremost step in the conservation of traditional germplasm sources is to assess the various qualitative and quantitative features. Various scientists across the globe, have been studying the genetic diversity, morphological characteristics and fungal activities on rice since appreciable amount of time. This has proved to be helpful in sustenance and refinement of the rice varieties.

Variability was accessed for quantitative and qualitative characters for 30 landraces. Notable variability was observed in the quantitative characters of the selected landraces. Highest variability was seen in ratio of length/breadth (l/b) without husk (25.55), followed by 50 kernel weight (25.51), kernel breadth without husk (21.21), ratio l/b with husk (19.19), kernel breadth with husk (17.90), kernel length without husk (16.58) and kernel length with husk (13.91). A dendrogram was generated by Ward's method from the data acquired. Ten selected rice varieties were screened for seed borne fungi by standard blotter paper method. The percentage of disease incidence and percentage of frequency were calculated.

The rice varieties Choman and Ponnaryan showed highest percentage of disease incidence (100). Lowest percentage of disease incidence was seen in Kumkumashala and Gandhakashala. Highest frequency of occurrence was shown by Aspergillus sps. Other fungal species reported were Chaetomium sps., Curvularia sps., Helminthosporium sps., Unidentified sps. from Dematiaceae, Phoma sps. and Trichococcus sps.