Studies on How Changing the Transplanting Time Affects Rice Quality and Yield

Abstract

This study was conducted to reset the transplanting period to produce high-quality rice in the South regions due to the rise in air temperature caused by global warming. From May 15 to June 25, transplants were performed five times every ten days. Quantity and quality were comprehensively reviewed, including watering season, ripened grain rate, head rice rate, head rice yield, protein content, and palatability. In the southern plains, medium-late and medium maturing cultivars yielded the most when transplanted on June 15, while early maturing cultivars yielded the most when transplanted on June 25. Considering the quality and quantity of rice, the optimal transplanting window for medium-late maturing cultivars is June 10-15, for medium maturing cultivars it is June 15-20, and for early maturing cultivars it is June 25. In the middle of the southern region, the highest yield was on June 25 for medium-late maturing and June 15 for medium maturing and early maturing. However, considering the quality, the best time for transplanting is June 10 for medium-late maturing, June 5 for medium maturing, and June 15 for early maturing. As a result of the rise in average temperature, the transplantation period was delayed by at least 4 to 16 days in all varieties and regions relative to the traditional transplantation duration. In summary, it is determined that a suitable transplanting period must be established in response to the increase in average temperature to ensure the production of high-quality rice.

Effect of Transplanting Date on Agronomic and Grain Quality Traits Using Early-Maturing Rice Varieties

“…Previous studies showed the same trends, indicating that protein content increased as the transplanting date was delayed [24][25][26][27] and early-maturing rice varieties showed higher protein content than mid-late-maturing rice varieties even when transplanted on the same date and with the same level of fertilizer applied [47], suggesting that rice with a higher protein content has a shorter vegetative period.…”

“…The grain filling stage is the period during which the rice grain is developing and filling with starch and the mean temperature during this stage can affect the physicochemical properties, starch structure, and appearance of rice grains [7][8][9][10][11][12]. In this study, there were significant differences in the head and chalky rice rates between the two rice varieties and these rates varied depending on the transplanting date since differences in the transplanting date can result in differences in temperature and sunlight exposure, which can affect the growth and development of rice plants [25][26][27] (Figure S1).…”

“…The head rice rate was different depending on the transplanting date, as environmental conditions such as temperature and sunlight exposure can vary depending on when the rice is transplanted [25][26][27]. Additionally, genetic differences between rice varieties can also play a role in determining head rice rate [40][41][42][43], so two rice varieties showed different head rice rates even though they had the same heading date of 17 July, shown by the 75.4% rate for Jinbuol transplanted on 1 June and 84.9% for Yeoreumi transplanted on 16 May.…”

“…The grain filling stage in rice varies relative to the heading date, which can be influenced by various factors such as rice variety, temperature, day length, and transplanting date. Several studies have reported that the transplanting date has a significant impact on the heading date of rice [25][26][27].…”