Seed Characteristics Affect Low-Temperature Stress Tolerance Performance of Rapeseed (Brassica napus L.) during Seed Germination and Seedling Emergence Stages

Abstract

Screening and breeding elite varieties with rapid germination and uniform seedling emergence under low temperature is an effective strategy to deal with the cold climate occurring under late sowing conditions in the Yangtze River basin. This study focused on the performance of seven functional traits, including percentage of germination, percentage of emergence, mean germination time, mean emergence time, total seedling length, total dry weight, and seedling vigor index of 436 natural rapeseed populations under normal-temperature (25/20 °C) and low-temperature (15/10 °C) conditions. Furthermore, ten genotypes were screened to verify their low-temperature tolerance based on cultivar traits in a pot experiment. The results show that the germination- and emergence-related functional traits of rapeseed genotypes exhibit rich genotypic diversity in response to low-temperature stress; the variation among these traits ranged from 1–25% under normal-temperature and 10–49% under low-temperature conditions. Variation in seed characteristics also affected the capacity for low-temperature tolerance in the process of seed germination and seedling emergence, and could explain 22% of the total variance for low-temperature stress tolerance indices. There existed high correlations between the stress tolerance index of total dry weight (STI_TDW) and thousand-seed weight, and between the stress tolerance index of emergence percentage (STI_PE) and oil content. The contents of erucic acid, glucosinolate, and eicosenoic acid were positively correlated with the stress tolerance index of mean germination time (STI_MGT) and mean emergence time (STI_MET). The D-CRITIC (distance-based intercriteria correlation) weight method was selected in this experiment to calculate each variety’s comprehensive low-temperature stress tolerance index by integrating the standard deviation and distance correlation coefficient of each index. The genotypes with large comprehensive low-temperature stress tolerance index also had higher low-temperature stress tolerance index of biomass and yield in the pot experiment, indicating that the comprehensive low-temperature stress tolerance index has high reliability and applicability. This study could provide a theoretical basis for the utilization of low-temperature-tolerant germplasm resources, as well as a reference for the cold resistance and yield stability under late- and direct-sowing conditions of rapeseed in the Yangtze River basin and other similar environments around the world.

Morpho-Physiochemical Indices and Transcriptome Analysis Reveal the Role of Glucosinolate and Erucic Acid in Response to Drought Stress during Seed Germination of Rapeseed

“…Therefore, GSL and EA can be considered as promising agents for enhancing the drought tolerance of LGLE seeds during the germination stage. Additionally, a previous study reported that priming with GSL and EA improved stress tolerance at the rapeseed seedling stage [ 82 ].…”

Effects of Seed Priming and Foliar Treatment with Ascorbate, Cysteine, and Triacontanol on Canola (Brassica napus L.) under Field Conditions

“…In the works of Sikorska et al [58] and Malhi et al [59], the plants from field experiments did not react to foliar fertilization with a greater seed yield. In multiple cases [60][61][62] in field and controlled trials, the abiotic conditions influenced the thousand seed weight, seed yield, seed germination, and seedling emergence of canola. In our work, despite the negative effect of the weather on PHA, NL, NS, and OC, the treatments increased these parameters.…”

Comparison and Evaluation of Low-Temperature Tolerance of Different Soybean Cultivars during the Early-Growth Stage

“…Generally, the response and sensitivity of crops to low temperatures depend on the growth stage [8,9]. The suitable germination temperature for soybean is approximately 30 • C, but the germination rate (GR) can be 50% at 17 • C [10].…”