Functional Trait Diversity among Wild Species of Rice in Sri Lanka.

Abstract

The diversity of agronomical characteristics of wild rice ( 0ryza) plays an important role in rice breeding programs worldwide. In this study, the morphological, physiological and anatomical characteristics of five wild rice species (0. nivara, 0. rufipogon, 0. eichingeri, 0. rhizomatis and 0. granulata) available in Sri Lanka were examined. Ten pots (replicates) for each wild rice species were selected for a garden experiment, in which pots were arranged in a complete randomized design. Overall, these five species are morphologically very different in terms of plant height, flag leaf length and width, panicle type, and ligule shape. 0. granulata and 0. nivara have compact panicles, 0. rufipogon has open panicles and both 0. eichingeri and 0. rhizomatis have intermediate type panicles. Physiological functions of the five wild rice species are different from each other. The rate of photosynthesis differed among five species under the same environmental conditions. The highest net photosynthetic rate (5.86 µmo! m·2 s·1), the highest cluster width of the base (61.4 µm), and trichome density (184.33 per 25mm2 area) were observed in 0. rufipogon compared to the rest, and such desirable traits are effective in rice breeding. 0. eichingeri and 0. rufipogon showed the highest significant transpiration rates and stomata! conductance. However, photosynthetically active radiation and sub stomata! CO2 concentration did not significantly differ among five species. The highest and the lowest stomata! density were recorded in 0. granulata and 0. nivara respectively. The highest trichome density was detected in 0. rufipogon and the lowest trichome density in both 0. eichingeri and 0. granulata. 0. eichingeri and 0. rufipogon showed significantly the highest number of buliform cells per cluster.