Early-season rice in the middle and lower reaches of the Yangtze River is vital for China’s food security, but the planting area has sharply decreased in recent years due to its poor appearance and taste quality, as well as low returns. Therefore, we collected and analyzed 334 early-season rice varieties released in the region from 2000 to 2022. To verify whether low-amylose content (L-Am) varieties can reduce chalkiness without compromising yield, two field experiments were conducted: a two-year consecutive experiment (2021–2022) using six representative varieties (low amylose, L-Am: 14.5–16.8%; medium-high amylose, MH-Am: 23.8–25.9%), and a one-year validation experiment (2024) utilizing 32 widely cultivated varieties. The results indicated that the amylose content (AC) of the 334 varieties showed a normal distribution, with varieties containing 18–20% AC being the most prevalent (23.6%), which resulted in L-Am varieties collectively accounting for 46.4%; additionally, AC was significantly positively correlated with chalky kernel rate (CKR) and chalkiness degree (CKD), and negatively correlated with panicles per m2 and length–width ratio (LWR), but showed no correlation with yield. Similarly, L-Am and MH-Am varieties achieved comparable yields through compensatory adjustments in field experiments: L-Am varieties had 12.8–13.9% more panicles per m2 but 3.6–7.3% lower 1000-grain weight. Moreover, L-Am varieties exhibited superior grain quality, with 70.8–73.5% and 54.0–62.1% lower CKR and CKD, respectively. Physiological analyses revealed that L-Am varieties exhibited a smaller maximum grain-filling rate (GFRmax) and amylose accumulation rate (GAmRmax), mean grain-filling rate (GFRmean) and amylose accumulation rate (GAmRmean), longer active grain-filling/amylose accumulation periods (D), and higher activities of soluble starch synthase (SSS) during grain-filling stages. These results demonstrate that early-season rice varieties with low AC tend to exhibit significantly lower chalkiness. Physiologically, this superior appearance quality is strongly associated with maintained yield through compensatory yield components and distinct starch synthesis kinetics, offering a practical strategy for enhancing both quality and productivity in early-season rice.
Wu et al. (Sat,) studied this question.