Abstract:

To fully explore the yield and quality potential of japonica rice with good taste quality by machine transplanting under straw returning in Huaibei area, medium-maturing medium japonica rice ‘Nanjing 2728’and late-maturing medium japonica rice ‘Nanjing 9108’ were used as the test materials. Two treatments were set, which were machine-transplanted rice with long-seedling-age of 30 days and conventional seedling-age of 20 days (CK) in high yield cultivation condition. The yield formation and quality characteristics of good taste quality japonica rice with two different seedling ages were systematically compared. The results showed that, compared with that of CK, the grain yield of late-maturing medium japonica rice of long-seedling-age increased by 3.24%-5.01%, the difference was significant, while the grain yield of medium-maturing one increased by 1.79%-1.85%, and the difference was not significant. Getting enough spikes and more numbers of grains per panicle, and maintaining high seed setting rate and 1000-grain weight were the main causes of high yield of long-seedling-age machine-transplanted rice. Compared with CK, the long-seedling-age machine-transplanted rice could prolong the seedling age by about 10 days and the whole growth period was prolonged by 5-7 days. Although the basic seedlings at transplanting period was not as good as that of CK and the number of tillers was smaller in the whole growth period, the individual superiority of the long-seedling-age rice was more prominent, and the photosynthetic system was better in the middle and late period of the population, the dry matter accumulation and harvest index were high, and the final yield was good. Compared with CK, the long-seedling-age machine-transplanted japonica rice had higher head milled rice rate, good appearance quality and cooking and eating quality; its peak viscosity, hot pulp viscosity, final viscosity and breakdown value were all higher than those of CK, and the difference was significant; while the setback value showed the opposite trend, which was significantly lower than that of CK. The quality of japonica rice with good taste quality was improved by long-seedling-age machine-transplanting technique. According to the demand of rice production in Huaibei area, we can further study the supporting cultivation technology of long-seedling-age machine-transplanted rice, and promote the demonstration and application of the technology.

Key words: machine-transplanted rice, good taste quality japonica rice, long-seedling-age, yield, quality