Early-season rice often faces limited market competition due to its lower quality, which diminishes farmers' incentives to cultivate it. Developing specific early-season rice varieties tailored for rice noodle production represents a practical solution to this challenge. However, limited information exists on the varietal differences regarding the yield and quality of noodles produced from early-season rice and their determinants. To address this gap, this study conducted field experiments with 15 early-season rice varieties during 2022 and 2023. The results revealed significant varietal differences in rice noodle yield per unit of land area and cooking and eating (texture) qualities of the noodles, with the variety Zhuliangyou 4024 standing out for its ability to produce rice noodles that are both high yielding and of superior cooking and eating qualities. Correlation analysis showed the yield of rice noodles per unit of land area was significantly related to grain yield per unit of land, which in turn was linked to grain weight. Additionally, the analysis showed the cooking loss rate of rice noodles and their chewiness were significantly correlated with both amylose and amylopectin content, whereas the hardness, springiness, and resilience of cooked rice noodles were significantly correlated only with amylose content. However, partial correlation analysis indicated that all these quality traits were significantly correlated solely with amylose content when controlling the influence of other chemical properties. These findings indicate that selecting early-season rice varieties with high grain weight and high amylose content can lead to the production of high-yield and high-quality rice noodles.

Grain-filling, as the final growth stage of rice, is sensitive to environmental temperature change. Previous studies mainly concerned about the effects of high temperature stress during grain-filling on rice growth, and most experiments were carried out with pot for cultivating rice and greenhouse for warming. This research investigated the response of rice grain-filling of superior spikelets (SS) and inferior spikelets (IS) of two japonica cultivars to elevated temperature during grain-filling stage under open-field warming conditions in lower reaches of Yangtze River Basin using free-air temperature enhancement facility. Results indicated that rice yield was not significantly changed by warming less than 4°C. SS and IS showed different responses to elevated temperature during the grain-filling stage, whereas there were similar trends between two cultivars and years. For SS, although elevated temperature enhanced its filling rate during the early grain-filling period, and caused a shorter grain-filling period and a lighter grain weight; for IS, elevated temperature improved its grain weight by enhancing its filling rate during middle and late grain-filling period due to the increased number of days with suitable temperature. For both SS and IS, key starch biosynthesis enzymes and indole-3-acetic acid content exhibited generally a similar dynamics trend with grain-filling rates, and these sink strength parameters presented higher levels under elevated temperature relative to natural temperature for IS during middle and late grain-filling period. Consequently, warming less than 4°C presented different influences on SS and IS; the improvement of IS filling under warming regime was associated with the intensification of grain sink strength.