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Improving grain quality is critical to the development of hybrid rice. In recent years, multiple hybrid rice cultivars with superior grain quality have been developed in China through dedicated breeding efforts. However, limited information is available on yield performance and yield formation characteristics of these high-quality hybrid rice cultivars. In this study, field experiments were conducted to compare yield attributes between a recently developed indica hybrid rice with superior grain quality (Jingliangyou 1468, JLY1468) and a relatively older indica hybrid rice cultivar with high yield potential (Liangyoupeijiu, LYPJ). Results showed that grain yield was 13–17% higher in JLY1468 than in LYPJ. The higher grain yield of JLY1468 than of LYPJ was mainly attributable to a higher spikelet filling percentage, which was closely related to a higher harvest index resulting from a higher crop growth rate during the post-heading period. The results of this study suggest that late-stage vigor may be a vital trait for the development of indica hybrid rice cultivars with both high quality and high yield.

Previous studies have shown that matrine, a natural compound extracted from the herb Sophora flavescens, has a good anti-leukemia effect, but its key target and mechanism remains unclear. Here, we found that only c-Myc could respond rapidly to matrine treatment in three myeloid leukemia cell lines, and matrine inhibited both transcription and translation of c-Myc. Ribosome biogenesis and nucleotide metabolism, the key downstream of c-Myc, were significantly suppressed after matrine treatment. Therefore, our results confirmed that matrine is a special c-Myc inhibitor which suppresses ribosome biogenesis and nucleotide metabolism by inhibiting c-Myc in myeloid leukemia. This study provides scientific basis for the development of matrine derivatives to c-Myc-driven cancers.

The demand for and consumption of soft-textured, high-quality rice with low amylose content have substantially increased in China with improved economic and living standards. Shifting sowing date is a common strategy to optimize temperature conditions and improve rice quality. In this study, a high-quality rice cultivar with low amylose content (Jingliangyou 1468) was grown under four sowing dates (May 15th and 25th, and June 4th and 14th) in 2019 and 2020 to determine the effects of sowing date on palatability-related traits and evaluate relationships between palatability-related traits and daily mean temperature during the grain-filling period. Results showed that delaying sowing date decreased daily mean temperature during the grain-filling period and consequently increased amylose content and setback viscosity of milled rice flour, which in turn increased hardness and chewiness of cooked rice. The finding of this study suggests that the strategy of delayed sowing does not improve the palatability of high-quality rice in the context of consumers’ preference for soft-textured rice.

Field experiments were conducted to compare two hybrid rice cultivars—a recently released high-quality cultivar (Jingliangyou 1468, JLY1468) and a relatively older cultivar (Liangyoupeijiu, LYPJ). Results showed that hardness, springiness, cohesiveness, resilience, and chewiness of cooked milled rice were all lower in JLY1468 than in LYPJ, due to its lower amylose content and altered paste properties of milled rice flour. Active digestion duration of cooked milled rice was 26% shorter and the glucose production rate from starch digestion was 33% faster in JLY1468 compared with LYPJ. Texture and starch digestion properties of cooked milled rice as a factor of temperature during the grain-filling period were different between LYPJ and JLY1468 due to differing amylose contents and gel consistencies of milled rice flour in response to temperature. This study highlights that attention should be paid to potential health risks associated with the development of high-quality hybrid rice cultivars with soft texture.

Head milled rice is the main form of rice for sale and consumption. However, previous studies on the yield change due to the development of new cultivars in rice generally focus on grain yield but few on head milled rice yield. In this study, field experiments were conducted in two years (2019 and 2020) to compare head milled rice yield and associated traits (grain yield, milled recovery traits, and shape and chalkiness traits of rice grains) between two middle-season hybrid rice cultivars released 18 years apart, i.e., Jingliangyou 1468 (JLY1468), a recently-released cultivar with high eating quality, and Liangyoupeijiu (LYPJ), an old cultivar with high grain yield. JLY1468 had higher head milled rice yield than LYPJ by 30% in 2019 and by 33% in 2020. The higher head milled rice yield in JLY1468 than in LYPJ was attributable to improvements in both grain yield, and head milled rice rate (HMRR). The improvement in HMRR in JLY1468 compared to LYPJ was mainly attributable to a reduction in chalkiness degree, which was associated with a decrease in rice grain size. The results of this study provide evidence for the improvement in head milled rice yield in middle-season hybrid rice with the development of new cultivars in recent years.

The production of middle-season rice is an important part of agriculture in the Yangtze River basin of China. In recent years, the chalky grain rate of middle-season rice has decreased with the release of new cultivars. However, limited information is available on the factors responsible for this change in the chalky grain rate. This study evaluated the trends in the chalky grain rate and grain size traits of the new cultivars and the relationships between the chalky grain rate and grain size traits for middle-season hybrid rice in a province located in the middle reaches of the Yangtze River basin during 2006–2021. The results indicate that the recently reduced chalky grain rate of middle-season hybrid rice in the new cultivars is closely associated with a decrease in rice width, suggesting that it is feasible to reduce the chalky grain rate of middle-season hybrid rice by slimming the grain through breeding.

Consuming rice with low starch digestibility is beneficial for reducing the risk of diabetes. Several factors have been shown to influence starch digestibility, but the combined effects of these factors on starch digestibility have not been studied. We assessed multidimensional relationships between the glucose production rate (GPR) of cooked rice with 16 indexes, including physicochemical, pasting and textural properties in 30 rice varieties. The stepwise multiple regression analysis showed that amylose content (AC), gel consistency (GC) and pasting temperature (PT) were closely related to GPR. This relationship could be described by the equation: GPR = −0.080 AC + 0.008 GC + 0.034 PT + 0.720, with a determination coefficient of 0.84. The variation partitioning analysis further indicated that AC, GC and PT independently explained 36%, 5% and 4% of the GPR variation, respectively. The interaction of AC and GC explained 46% of the variation in GPR. This study identifies the key indexes (AC, GC and PT) affecting starch digestibility and quantifies contributions of these indexes to the variation in GPR. The finding of our study provides useful information for breeding and selecting rice varieties with low GPR.