재배시기와 질소시비 수준에 따른 녹미의 특성 변이

Grain Characteristics of Green-Kerneled Rices under Different Planting Time and N-fertilizer Levels

This study was carried out to investigate the cultural conditions for optimizing kernel greenness in order to obtain basic information for breeding and cultivation of green-kerneled rice varieties. Thirty-days-old seedlings of two green-kerneled varieties, Hexi41 (China) and Saengdongchalbyeo (Korea) and one regular variety, Ilpumbyeo, were transplanted on 24 May (early), 9 June (medium), and 24 June (late) in 2004 under three different N-fertilizer levels, N-P₂O₅-K₂O=6-8-8 kg/10a(), 12-8-8kg/10a, and 18- 8-8kg/10a. Panicles were sampled from 20 days after heading (DAH) to 50 DAH with a five-day interval. The greenness of hulled rice was measured by colorimeter (MINOLTA CR-200). Kernel greenness of Saengdongchalbyeo was the highest with a greenness score of -10.09 in medium planting time with medium N-fertilization, which 3.54 times darker than that of Hexi41 which showed the greenness score of -2.85. Kernel greenness was significantly affected by planting time and N-fertilizer level in Hexi41. On the other hand, kernel greenness of Saengdongchalbyeo was not affected by cropping season and N-fertilizer level, indicating that Saengdongchalbyeo might be a better germplasm source in breeding program for green-kerneled rices. Two green-kerneled varieties, Saengdongchalbyeo and Hexi41, showed significant changes in kernel-greenness under four different temperature regimes at ripening stage, indicating that the kernel greenness maintained under low air temperature less than 21oC. Fourty days after heading seemed to be the optimal harvesting time which assure the highest yield and proper kernel-greenness. However, kernel greenness was significantly affected by heading dates, and thus late heading followed by low temperature during ripening was likely to be a basic requirement to ensure the kernel greenness.