Abstract:

【Objective】 The change rule of cooking and eating qualities of three growth-development types of Japonica rice varieties was studied. 【Method】 A field experiment was carried out with 50 Japonica rice varieties of three growth-development types adopted in the region of Yangtze River, to study the effects of four nitrogen levels (zero, low, medium and high) on the difference in cooking and eating qualities. Variety difference of taste value in response to nitrogen levels was also discussed and their types were also classified. 【Result】 The main results showed that in the range of 0-300 kg?hm-, with the level of nitrogen increased, the amylase content, gel consistency and taste value of Japonica rice varieties decreased. The taste value and amylase content increased with extension of the growth duration, and the effect on gel consistency was on the contrary. All the 50 rice cultivars could be classified into three types (insensitive, intermediate and sensitive) in terms of their different responses of taste value to nitrogen application levels. And two rice groups among them were also recommended. One group was the varieties with high and stable taste value under all nitrogen levels, the other group was the varieties which were sensitive to nitrogen application levels, and good cooking quality could be obtained through proper reducing nitrogen application. 【Conclusion】 In the range of 0-300 kg?hm-, with the nitrogen level increased the amylase content and gel consistency of Japonica rice varieties decreased. The sensitivity of rice taste value to nitrogen fertilizer is different among varieties.

Key words: rice')">rice, growth-period type, nitrogen level, cooking and eating qualities