Abstract:

A field experiment was carried out with three different types of rice varieties (conventional late japonica rice,
hybrid late japonica rice, and hybrid medium indicia rice) to study the effects of four nitrogen application levels (0, 150,
225, and 300 kg/hm2) on their differences in eating qualities. The main results showed that with increasing nitrogen fertilizer
amount, the hardness, cohesiveness, resilience, and chewiness increased at first and then decreased, whereas adhesiveness
exhibited the opposite trend, with 225 kg/hm2 being the turning point for both trends. Neither nitrogen fertilizer nor rice
type affected springiness. Aroma, gloss, taste, texture and taste value decreased whereas integrity increased with increasing
nitrogen application. The eating quality of conventional late japonica rice was the best, followed by that of hybrid late
japonica rice and hybrid medium indicia rice. The three rice cultivars differed in their sensitivities to nitrogen fertilizer in
the decreasing order: hybrid medium indicia rice, hybrid late japonica rice and conventional late japonica rice. Hardness
displayed a significantly positive correlation with adhesiveness, cohesiveness, chewiness, resilience, and integrity, but a
significantly negative correlation with adhesiveness, aroma, gloss, taste, texture and taste values. There was a significant
correlation between taste values. In addition to the springiness and cohesiveness, other textural properties showed a
significant correlation with taste values.

Key words: conventional late japonica rice, hybrid late japonica rice, hybrid medium indicia rice, nitrogen fertilizer, textural properties, taste value