Maize (Zea mays, L.) cultivation has expanded greatly from tropical to temperate zones; however, its sensitivity to chilling often results in decreased germination rates, weak seedlings with reduced survival rates, and eventually lower yields. We conducted germination tests on the maize-282-diverse-panel (282 inbred lines) under normal (25 °C) and chilling (8 °C) conditions. Three raw measurements of germination were recorded under each condition: 1) germination rate, 2) days to 50% germination, and 3) germination index. Three relative traits were derived as indicators of cold-tolerance. By using the 2,271,584 single nucleotide polymorphisms (SNPs) on the panel from previous studies, and genome-wide association studies by using FarmCPU R package to identify 17 genetic loci associated with cold tolerance. Seven associated SNPs hit directly on candidate genes; four SNPs were in high linkage disequilibrium with candidate genes within 366 kb. In total, 18 candidate genes were identified, including 10 candidate genes supported by previous QTL studies and five genes supported by previous gene cloning studies in maize, rice, and Arabidopsis. Three new candidate genes revealed by two associated SNPs were supported by both QTL analyses and gene cloning studies. These candidate genes and associated SNPs provide valuable resources for future studies to develop cold-tolerant maize varieties.

No abstract

No abstract

To clarify the effect of plant spacing on the growth, yield formation, and quality of sugar beet taproot. We designed field experiments in 2021-2022, and sugar beet variety KWS1176 was used as experimental material, and 9 plant spacing treatments from 8cm to 32cm were set up. The morphological indicators, photosynthetic characteristics, and the nutrient contents were determined at the stages of the leafage growing period (V1), sugar increase period of taproot (V2), sugar accumulation period I of taproot (V3), and sugar accumulation period II of taproot (V4), and the root yield and quality parameters were measured at the harvest. The results showed that in the plant spacing treatments of 11cm and 14 cm, sugar beet had a suitable canopy structure and space for taproot growing. The canopy photosynthetic activity was higher, which provided sufficient photosynthetic products for root growth, and appropriate root size could balance root growth and sucrose accumulation. The highest root yield and sugar content were also obtained in the treatment of 14 cm plant spacing. With the increase of plant spacing, the yield of sugar beet decreased, and the content of α-amino N, K+, and Na+ in the root increased, which had a disadvantageous influence on the processing quality of the root. It was found that the number of cambial rings and the average distance between cambial rings could be used as qualitative indicators of the sugar content of taproot and the processing quality. Therefore, 11cm-14cm was recommended as a reasonable planting spacing to obtain higher taproot and sugar yield with better quality.

Neutral detergent fiber (NDF) content was the critical indicator of fiber in corn stover. This study aimed to develop a prediction model to precisely measure NDF content in corn stover using near-infrared spectroscopy (NIRS) technique. Here, spectral data ranging from 400 to 2500 nm were obtained by scanning 530 samples, and Monte Carlo Cross Validation and the pretreatment were used to preprocess the original spectra. Moreover, the interval partial least square (iPLS) was employed to extract feature wavebands to reduce data computation. The PLSR model was built using two spectral regions, and it was evaluated with the coefficient of determination (R2) and root mean square error of cross validation (RMSECV) obtaining 0.97 and 0.65%, respectively. The overall results proved that the developed prediction model coupled with spectral data analysis provides a set of theoretical foundations for NIRS techniques application on measuring fiber content in corn stover.