ABSTRACT. Grain size is an important trait that directly influences the yield of rice. Validation and evaluation of grain genes is important in rice genetic studies and for breeding. In a population of 240 recombinant inbred lines (RILs) derived from a cross between an extra-large grain japonica variety TD70 and a small grain indica variety Kasalath, we mapped 19 QTLs controlling grain traits. These QTLs included six cloned grain genes, namely, GW2, GS3, qSW5, qGL3, GS5, and GW8. All of the alleles with the optimal effects on grain size came from TD70, the variety with extra-large grains. To verify these gene loci, we cloned and sequenced GW2, GS3, GW5 (qSW5), qGL3, GS5, GW8, and TGW6 in TD70 and Kasalath, and found several functional polymorphisms in the sequences of the genes. New functional markers for the cloned genes were designed to identify parents and RILs. The contributions of these polymorphisms to the improvement in rice grain size traits were evaluated. Our results indicate that at least six functional polymorphisms have additive effects on grain shape and that one non-functional polymorphism in TGW6 affects grain shape in TD70. The newly designed markers will be useful in further studies to identify functional grain genes. Our findings provide insight into the control of grain size in rice, and they will be of value for improving rice grain yield.

Background: Selenium (Se) is an essential trace element to higher plants, animals and humans, but low Se levels are a global public health concern. Seed priming has become a basic strategy for the production of Se-riched agricultural products, but its application is still not clear in the production of Se-enrich alfalfa, hence this study was conducted for the production of Se-enriched alfalfa by seed priming with different concentrations and time on seed vigour. Methods: Seeds were primed with 0, 0.5, 1.0, 2.0, 4.0 and 8.0 mmol L-1 of sodium selenite solution for 0, 3, 6, 9 and 12 h at 20°C and their germination percentage, germination index, seedling vigour index and mean germination time were analyzed. Result: Seed vigour of alfalfa was improved by priming with low selenium (Se) concentration (0.5 and 1.0 mmol L-1), but was inhibited by high Se concentration ( greater than 2.0 mmol L-1). Hence, it must be necessary to carefully select appropriate concentration and time for the application of Se priming in alfalfa seeds. The optimal manner of Se priming in alfalfa seeds might be at 1.0 mmol L-1 concentration for 9 h.

SummaryHaemoglobin H (Hb H) disease (intermediate status of α‐thalassemia) shows marked phenotypic variability from asymptomatic to severe anaemia. Apart from the combined β‐thalassemia allele ameliorating clinical severity, reports of genetic modifier genes affecting the phenotype of Hb H disease are scarce which bring inconvenience to precise diagnosis and genetic counselling of the patients. Here, we present a novel mutation (c.948C>A, p.S316R) in the PIP4K2A gene in a female Hb H disease patient who displayed moderate anaemia and a relatively high Hb H level. Haematological analysis in her family members revealed that individuals carrying this mutation have upregulated β‐globin expression, leading to a more imbalanced β/α‐globin ratio and more Hb H inclusion bodies in peripheral red blood cells. According to functional experiments, the mutant PIP4K2A protein exhibits enhanced protein stability, increased kinase activity and a stronger regulatory effect on downstream proteins, suggesting a gain‐of‐function mutation. Moreover, introduction of the S316R mutation into HUDEP‐2 cells increased expression of β‐globin, further inhibiting erythroid differentiation and terminal enucleation. Thus, the S316R mutation is a novel genetic factor associated with β‐globin expression, and the PIP4K2A gene is a new potential modifier gene affecting the α‐thalassemia phenotype.