In this study, four proso millet varieties with significantly different amylose and protein contents were used to explore the effects of amylose and protein contents on the visual appearance and eating quality of proso millet. The results showed that the viscosity, gelatinization time and gelatinization temperature of whole proso millet flour, as well as the water absorption percentage, volume expansion percentage and hardness of cooked proso millet were significantly higher for the varieties with higher amylose content than those with lower amylose content, while the gelatinization enthalpy was lower than that of the varieties with lower amylose content. For the varieties with higher protein content, whole proso millet flour had lower paste viscosity, and cooked proso millet had lower water absorption percentage and volume expansion percentage but higher harness. Proso millet with higher amylose and protein contents had poorer cooking quality, higher energy consumption and longer cooking time. In conclusion, appropriately reducing the amylose and protein contents of proso millet can improve the palatability.

Photosynthesis is the basis of crop growth and is sensitive to stress. Smut (Sporisorium destruens) is the primary disease in the production of broomcorn millet (Panicum miliaceum L.). This study evaluated the effects of infection with S. destruens on the photosynthesis of the resistant cultivar (BM) and susceptible cultivar (NF). After inoculation, there was a decrease in the chlorophyll content, gas exchange parameters, and chlorophyll fluorescence of the two cultivars. Observation of the ultrastructure of diseased leaves showed that the chloroplasts and mitochondria had abnormal morphology, and some vacuoles appeared. RNA-seq was performed on the flag leaves after inoculation. In addition to the resistant and susceptible cultivars, the diseased leaves developed from inflorescences were defined as S2. The analysis showed that the pathways related to photosynthesis stimulated some differentially expressed genes (DEGs) after infection with S. destruens. More DEGs were induced in the susceptible broomcorn millet NF than in the resistant broomcorn millet BM, and most of those genes were downregulated. The number of DEGs induced by S2 was greater than that in susceptible cultivar NF, and most of them were upregulated. These results indicate that infection with S. destruens affects the normal photosynthetic performance of broomcorn millet. Understanding the mechanism between S. destruens, photosynthesis, and broomcorn millet is an effective measure to prevent the occurrence of smut and enhance its resistance.

Nitrogen fertilizer is an important agronomic measure significantly affecting crop yield and grain quality. This two-year study aimed to explore the effects of four nitrogen levels on the morphology, lamellar and crystalline structure, pasting, and rheological properties of proso millet (PM) starch and to investigate potential food applications of PM. The results showed that the starch surface became uneven, and the structure of the starch granules shifted towards greater complexity with increasing nitrogen levels. Nitrogen increased the relative crystallinity, ordered structure, and average repeat distance, leading to a stable starch structure and a higher gelatinization enthalpy. Furthermore, nitrogen significantly increased peak, breakdown, setback, and final viscosities but decreased apparent amylose content, which caused the shear resistance and storage capacity of PM starch-based foods to deteriorate during processing and transport. Rheological analysis showed that PM starch exhibited the typical characteristics of a pseudoplastic fluid. Under nitrogen treatment, PM starch gels showed high potential for application in 3D printing products due to high resistance to shear thinning, gel strength, and yield stress, presumably owing to the significantly higher G´ than G´´, and the lower amylose content, which in turn promoted the formation of a stable network structure in water to immobilize more water. Our study provides a reference for applying PM starch in the food industry and for developing PM cropping-management programs to improve quality.

Boron (B) is an essential micronutrient for vascular plant growth. Both B deficiency and toxicity can impair tissue development in diverse plant species, but little is known about the effect of B on reproductive panicle development and grain yield. In this study, a mutant of Setaria italica exhibiting necrotic panicle apices was identified and designated as sibor1. Sequencing revealed a candidate gene, SiBOR1, with a G-to-A alteration at the seventh exon. Knockout transgenic lines generated by clustered regularly interspaced short palindromic repeats and their associated protein-9 also had necrotic panicles, verifying the function of SiBOR1. SiBOR1 encoded a membrane-localized B efflux transporter, co-orthologous to the rice BOR1 protein. SiBOR1 was dominantly expressed in panicles and displayed a distinct expression pattern from those of its orthologs in other species. The induced mutation in SiBOR1 caused a reduction in the B content of panicle primary branches, and B deficiency-associated phenotypes such as thicker cell walls and higher cell porosity compared with Yugu 1. Transcriptome analysis indicated that differentially expressed genes involved in cell wall biogenesis, jasmonic acid synthesis, and programmed cell death response pathways were enriched in sibor1. qPCR analysis identified several key genes, including phenylalanine ammonia-lyase (SiPAL) and jasmonate-ZIM-domain (SiJAZ) genes, responsive to B-deficient conditions. These results indicate that SiBOR1 helps to regulate panicle primary branch development to maintain grain yield in S. italica. Our findings shed light on molecular mechanisms underlying the relationship between B transport and plant development in S. italica.

To elucidate the mechanism by which intercropping proso millet (Panicum miliaceum L.) with mung bean (Vigna radiata L.) increases proso millet yield and to determine how this higher yield results from maximization of resources use efficiency, we designed and conducted four strip intercropping row arrangements, including two rows of proso millet alternating with two rows of mung bean (2P2M), four rows of proso millet alternating with two rows of mung bean (4P2M), four rows of proso millet alternating with four rows of mung bean (4P4M), two rows of proso millet alternating with four rows of mung bean (2P4M), sole proso millet (SP, control) and sole mung bean (SM, control) in Yulin, Shaanxi, China. Photosynthetically active radiation (PAR) in the canopy, radiation use efficiency (RUE), leaf photosynthetic characteristics, dry matter accumulation and allocation, and yield of proso millet were investigated. The results showed that the intercropping systems had higher PAR than the monoculture. Mean PAR intensities were increased by respectively 2.2%–23.4%, 19.8%–59.7%, and 61.2%–133.3% in the proso millet upper, middle and lower canopies compared with SP. The increase in PAR directly increased RUE, a result attributed mainly to the increase in photosynthetic capacity, including net photosynthetic rate and chlorophyll content. These responses resulted in increased dry matter allocation to plant organs. Yield of intercropped proso millet was 6.8%–37.3% higher than that under monoculture and the land equivalent ratios for the different intercropping patterns were all greater than unity (> 1). In general, yield followed a positive linear function of PAR in the intercropping system. The results indicated that intercropping can boost proso millet yield, evidently by altering light distribution within its canopy and consequently increasing RUE, thereby increasing leaf photosynthetic capacity, dry matter accumulation, and allocation to the grain. The optimum combination for improving the growth and yield of proso millet on the Loess Plateau of China was 2P4M.