Germination characteristics of Korean and Southeast Asian redrice (Oryza sativa L.) seeds as affected by temperature

Abstract

Red rice (Oryza sativa L.) is considered an important weed in many paddy fields. We performed a laboratory investigation to evaluate the germination percent, germination speed and days to 50% germination (T50) of red rice seed three groups were selected: (1) four Southeast Asian varieties/germplasms, (2) six Korean varieties/germplasms with enhanced yield and (3) four Korean varieties/germplasms which are problem in direct-sown paddy fields. The selected varieties/germplasms were incubated at four different day/night temperature settings: 15/10, 20/15, 25/20 and 30/25°C. This study has been carried out at phytotron and glass house between 2007 through 2009 to find out the characteristics of Asian redrice germ plasms. According to results, the germination percent and germination speed of red rice seed generally increased with increasing temperature. At low temperature (20/15°C), red rice seeds, selected or imported red rice from cold areas, resulted in lowest germination percent (9%) and germination speed (12.3), however, T50 was the lowest (7.2 at 15/10°C) compared to all the Southeast Asia red rice varieties/germplasms. Germination characteristics of Korean red rice seeds showed similar responses to temperature conditions depending on where they came from and local temperature: southern part of Korea (Hapcheon) or northern part (Suwon). However, Yeongcheon red rice showed high germination percent (96-100%) and low T50 (9.0-2.7) which was very similar to group 2 which were already selected as cultivars/germplasms for high vigor and high yield. The critical temperature for red rice germination related characteristics was 25/20°C and activity (germination speed and T50) did not increase much at 30/25°C. In conclusion, red rice varieties/germplasms selected from a local area would represent the temperature of the area partially. © 2010 Asian Network for Scientific Information.