Abstract:
Traditional rice gene pool in Sri Lanka consists of various biotic and abiotic
stress tolerant cultivars. Some of the traditional rice cultivars have been
studied in systematic way to understand their ability to withstand drought,
salinity and submergence stresses at different growth stages. The selected
rice cultivars can be directly introduced in to farmer field or can be utilized
as initial breeding materials for the production of rice cultivars with such
tolerances. This needs prior understanding on their agronomy, phenotype
and their potential yield in farmer field. The yield potential and fertilizer
responsiveness of traditional rice cultivars are known to be less than those
of modern rice cultivars. With the objectives of understanding agronomic
characters, yield potential and fertilizer responsiveness of the traditional
rice cultivars, a field experiment was carried out in 2011 Yala season at
Faculty of Agriculture, University of Ruhuna. A standard fertilizer
recommendation (recommended dose) has been introduced by Department
of Agriculture in Sri Lanka for modem rice cultivars. In this study three
fertilizer levels; Vi of the recommended dose, recommended dose, two folds
of the recommended dose and no fertilizer application was studied at the
field condition for forty traditional rice cultivars. Rice cultivars were
transplanted according to completely randomized block design with four
replicates. Each replicate consisted of three rows of rice plants and data
were collected from 20 plants of the middle row. Agronomic characters
such as plant height (cm), number of tillers/plant, number of leaves/tiller
and yield/plant were evaluated during the study period and bio mass indices
were calculated at the end of the experiment. According to statistical
analysis there were significant effects, of fertilizer on plant height, tiller
number and on number of leaves/tiller. According to correlation analysis
none of these agronomic characters correlated with yield/plant since these
varieties belonged to different age groups. The best fertilizer level for the
highest yield must be recommended for individual cultivar. Furthermore,
bio mass index of each rice cultivar at different fertilizer level is also a
factor to be considered.
