Crop Science最新文献

This research aims at identifying candidate genes associated with the accumulation of seed protein and sulfur amino acids (SAAs) by comparing the expression profile of genes in developing seeds of pea (Pisum sativum L.) lines. Lines were selected from PR-25, a recombinant inbred line population, derived from a cross between CDC Amarillo and CDC Limerick. The selected lines were high seed protein concentration (SPC) line PR-25-69, high SAA line PR-25-53, and low SPC and low SAA line PR-25-6. These lines were grown in a phytotron chamber, and developing seeds collected from three biological replicates of each line at 7, 14, 21, and 28 days after anthesis were used for RNA sequencing. By comparison of the gene expression profiles between SPC contrasting lines (PR-25-69 vs. PR-25-6) and SAAs contrasting lines (PR-25-53 vs. PR-25-6), 4920 differentially expressed genes (DEGs) were identified over the four time points. Of these, 2798 DEGs were downregulated and 2122 DEGs were upregulated compared to control (PR-25-6). The expression levels of the identified DEGs varied from log₂ twofold to log₂ 10-fold. Extensive transmembrane activities, including transportation of amino acids and proteins, were seen in the results of GO analyses. Downregulated DEGs represented 78 significant GO terms, while upregulated DEGs represented 52 significant GO terms. Some distinct biological processes were exclusively present in upregulated DEGs, for instance, reproduction and nutrient reservoir activities. Future studies will involve genetic variant analyses and the development of genetic markers based on the candidate genes.

Canola (Brassica napus L.) yields in Canada are not increasing sufficiently to meet future global demands. Improving photosynthetic efficiency and optimizing photoassimilate allocation represent a promising strategy to enhance yield potential. This study evaluated the photosynthetic and agronomic traits of 168 diverse canola accessions belonging to six pedigree groups: spring canola × spring canola (SP × SP), spring canola × winter canola (WI × SP), spring canola × rutabaga (B. napus var. napobrassica) (SP × RU), (winter canola × spring canola) × rutabaga ([WI × SP] × RU), spring canola × B. oleracea (SP × BO), spring canola × B. rapa (SP × BR), and accessions collected from the Plant Gene Resources of Canada, Saskatoon collection. Field experiments conducted over three growing seasons in Central Alberta, Canada, identified moderate to high heritability for four chlorophyll fluorescence parameters and five agronomic traits. Distinct source-sink allocation strategies emerged among pedigree groups. The SP × SP group optimized resource allocation for maximal seed yield, while winter canola-derived groups prioritized seed size (1000-seed weight) while maintaining competitive yields, likely through extended grain-filling periods. Unique physiological linkages were observed in progenitor-derived groups: SP × BR accessions exhibited coordinated regulation of non-photochemical quenching photoprotection, biomass production, and yield, whereas SP × BO demonstrated an association between root biomass and reduced minimal fluorescence (F_o′), suggesting improved PSII efficiency. These findings highlight the value of physiological trait-based selection in canola breeding. The identified germplasm and trait relationships provide a foundation for developing improved spring canola cultivars through targeted integration of favorable photosynthetic and allocation characteristics.

The increase in herbicide-resistant weeds and new political guidelines force farmers to change their weed management strategies while reducing herbicides. Current study aimed to explore the potential of equal space seeding (ESS) in maize (Zea mays L.) compared to conventional row seeding (CRS) regarding weed suppression and crop development. A multisite experiment was carried out in 2022 in southwestern Germany comparing ESS and CRS by pooling the data of three treatments (untreated, herbicide, and hoeing) of each system. The parameters leaf area index (LAI), photosynthetic active radiation (PAR), maize and weed biomass, and grain yield were measured. The ESS was neither statistically different in terms of LAI and PAR absorption nor did it show a higher weed suppression due to a reduced weed biomass compared to CRS. Although two of three trials also showed no differences between both systems in grain yield, the experiment with the lowest rainfall and irrigation amount as well as the evaluation across all three sites showed a significant increase in yield from ESS (5.72 Mg ha⁻¹) compared to CRS (3.77 Mg ha⁻¹). It was assumed that a reduced intraspecific competition, a slightly higher PAR absorption during maize flowering, and an improved root growth contributed to the higher yields in the ESS system. For more evidence as well as for a reliable recommendation for a specific cropping system, further studies in different environments are needed.

Little is known about seed development and its contribution to seed yield components in orchardgrass (Dactylis glomerata L.). Field trials were conducted in 2018 and 2019 to investigate orchardgrass seed development and the effects of four trinexapac-ethyl (TE) plant growth regulator and spring nitrogen (N) treatments on this process: untreated control, TE (210 g ai ha⁻¹), spring N (112 kg ha⁻¹), and TE + N. Regression analyses were used to elucidate seed development in three spikelet positions. In 2018, seed weight increased over growing degree days (GDD) in a bi-phasic segmented pattern in seed from distal and central spikelets but increases were linear from proximal spikelets. In 2019, seed weight increased in proximal spikelets following a bi-phasic segmented function, while seed weight increase in central spikelets was also bi-phasic, except for the TE treatment. Seed growth rate varied among spikelet positions, ranging from 0.22 to 0.34 mg GDD⁻¹ per 100 seeds. The seed growth rate varied among TE and N treatments, ranging from 0.31 to 0.47 mg GDD⁻¹ per 100 seeds. The TE + N treatment had the shortest seed filling duration and one of the smallest seed growth rate values, producing low seed weight. The TE + N treatment produced high seed number and yield, indicating a reduction in seed abortion or shattering. Seed carbon (C) and nitrogen (N) content increased during seed development and peak deposition preceded physiological maturity. No effects of TE on deposition of C or N in orchardgrass seed occurred.

Plant breeders utilize the additive main effects and multiplicative interaction (AMMI) model for analyzing yield data from multi-environment trials (METs) to visualize interaction patterns between genotypes and environments. AMMI-based selection indexes, such as the weighted average of absolute scores (WAAS) and the weighted average of absolute scores combining yield (WAASY), guide breeders in identifying superior varieties within METs. Despite being powerful, the frequentist approach of AMMI model and its derived indices presents challenges for identifying genotypes and environments, causing significant genotype-by-environment (G × E) interactions. This study built upon the Bayesian AMMI framework to allow to perform inferences on AMMI-based selection indexes. The Bayesian versions of WAAS and WAASY (Bayesian weighted average of absolute scores and Bayesian weighted average of absolute scores combining yield) were compared with the frequentist approach. A novel stability measure (SM), using Mahalanobis distance, was also proposed and integrated with yield performance into a graphical tool called the stability Mahalanobis trait (SMT) plot. Nine maize genotypes evaluated for grain yield across 20 environments were analyzed. The B-WAAS, B-WAASY, and SM indexes provided informative statistical inference through posterior distribution and credible intervals (highest posterior density [HPD]). HPD intervals allowed grouping similar genotypes based on stability and performance, offering reliable information for selection and recommendation. The SMT plot allows a direct comparison to an ideal scenario of high stability, facilitating the identification of genotypes aligned with breeding goals by analyzing the four quadrants. Genotypes in quadrant IV, exhibiting both high yield and high stability, are particularly valuable for breeding programs.

Gossypium hirsutum L. (cotton) yields are limited by heat stress. Breeding for heat tolerance is an important goal, yet the most important functional contributors to heat-induced yield loss must first be defined. Although Monteith defined crop yield decades ago as the product of intercepted photosynthetically active radiation, radiation use efficiency (RUE), and harvest index (HI), a review of heat stress effects on these functional yield drivers or their underlying processes is still needed for cotton. Heat stress is known to affect canopy development, which could impact radiation interception. Specifically, leaf area declines when plants are exposed to maximum air temperatures greater than 35°C. However, direct evidence for a yield-limiting decline in intercepted radiation under high temperature is lacking. Though information is limited in peer reviewed literature, RUE (photosynthetic efficiency of the canopy) may be an important contributor to heat-induced yield loss, and this review explores the heat sensitivity of RUE and underlying photosynthetic processes. HI is the ratio of economic yield to biological yield, and current evidence indicates that reproductive processes are more heat sensitive than vegetative growth processes. Therefore, lower HI is discussed as a potentially significant contributor to heat-induced yield loss, and the relative heat sensitivity of reproductive processes and specific yield components is explored in detail. In the future, there is a need for (1) field studies addressing the temperature responses of canopy-scale yield drivers, (2) further exploration of nighttime temperature effects, and (3) targeted selection for increased heat tolerance of physiological yield drivers.

The Northern Uniform Soybean Tests (NUST) are a regional field trial network coordinated by the United States Department of Agriculture to evaluate experimental soybean (Glycine max L.) strains developed by public institutions. Historical data from the NUST compiled, curated, and reported herein comprise a valuable multi-environment trial dataset including relevant elite soybean germplasm from maturity groups 00 to IV evaluated over 28 years in 199 locations, totaling 1652 environments. Our aim was to characterize the genetic structure of the NUST experimental strains, perform genome-wide association studies using historical phenotypic data, and assess the usefulness of these historical data for genomic prediction model training. Molecular marker information was collected on 2544 unique NUST experimental strains using the BARCSoySNP6K assay. High fixation index values between early and later maturity groups were observed in a region on chromosome 10 near the known soybean maturity gene E2. We failed to find strong genetic divergence between strains from different breeding programs, reflecting the germplasm sharing common among public programs. Genome-wide association analyses on important agronomic traits identified marker-trait associations, many of which overlap with quantitative trait loci previously reported in the literature. Genomic prediction models trained using the historical NUST data produced moderate to high predictive abilities in most cases, suggesting these data could make useful contributions to training sets. We have made these data publicly available as a data resource for others to study genotype–phenotype relationships within elite public soybean germplasm and develop predictive models for advancement and implementation of genomics-assisted breeding.

Ear rots and mycotoxin contamination of grain in maize (Zea mays L.) pose a threat to food production and safety, best ameliorated by breeding for resistance. In this study, we introgressed alleles conferring resistance to Fusarium ear rot and fumonisin contamination from GE440, a highly resistant inbred with poor agronomic performance, into LH132, a more susceptible but agronomically elite commercial inbred, to create lines with improved disease resistance without compromising grain yield or other agronomic traits. On average, the selected backcross lines and their topcross hybrids had less Fusarium ear rot and fumonisin content than their recurrent parent or its topcross hybrid, respectively. The most resistant backcross lines were superior to LH132 for resistance and produced hybrids with similar yield and agronomic performance. The backcross-derived lines were genotyped, facilitating the identification of two introgression regions conferring resistance to Fusarium ear rot and one for fumonisin content. These regions are large and contain hundreds of genes but are concordant with previous Fusarium ear rot resistance mapping studies, and the lines developed here can be used for higher resolution genetic mapping.

Mandated lowering of nicotine levels in combustible cigarettes is under consideration by some regulatory agencies. Technical feasibility of genetics-based strategies to achieve ultra-low nicotine levels (0.4–0.7 mg g⁻¹) in cured tobacco leaves in the absence of undesired correlated changes requires field evaluation. Use of naturally occurring or conventionally induced genetic variation to achieve this potential goal would likely be preferred. In this research, we generated 11 nearly isogenic lines (NILs) of flue-cured tobacco cultivar K326 or K326-like genotypes possessing different types of allelic variability affecting lower nicotine accumulation. Ten low-nicotine genotypes were evaluated in comparison with K326 in four field environments under conventional agronomic management. Only three NILs accumulated nicotine in weighted composite cured leaf samples at levels less than 0.7 mg g⁻¹. These materials displayed significant negatively altered cured leaf quality, however. Significantly reduced soilborne pathogen resistance was also observed in two of the lowest nicotine NILs. We also evaluated in two field environments nic1/nic1 nic2/nic2 NILs of K326, which possessed either the transcriptionally suppressed nic1 allele derived from LAFC53 or a nic1 deletion allele derived from TI 313. The latter NIL was found to accumulate significantly lower alkaloid levels but produced unacceptable cured leaf yields that were 47.6% lower than that for K326. Results suggest that it is not straightforward to develop ultra-low nicotine cultivars without unfavorably altering other characteristics, at least using currently characterized naturally existing or induced genetic variability.

Selenium (Se) is an essential trace element for humans and animals. It is involved in many biochemical processes in plants. It has significant effects on drought resistance, photosynthesis, pigment synthesis, and nutrient uptake in plants. Nevertheless, the bioavailability and biological activity of Se are relatively limited, limiting its widespread use in nature. Fortunately, the rapid development of nanotechnology has opened up new avenues for precision regulation in agriculture. Among them, nanoselenium, with its unique physical and chemical properties, has demonstrated excellent advantages in promoting plant growth and development and improving crop quality. It is particularly noteworthy that polysaccharide (PS), as an environmentally friendly dispersant, can effectively prepare stable and uniformly dispersed selenium nanoparticles (Se NPs), which are not only biocompatible, but also exhibit excellent bioactivity. Studies have shown that Se NPs can significantly enhance the photosynthetic rate and growth rate of crops, promote the optimal development of the root system structure, and thus improve the efficiency of soil nutrient uptake and utilization. However, there is still a lack of research on the application of polysaccharide selenium nanoparticles (PS-Se NPs) in agricultural practice. In fact, PS-Se NPs can not only further optimize crop quality and increase the accumulation of nutrients and functional constituents, but also significantly enhance crop stress tolerance and effectively reduce the negative impact of environmental stresses on crops. In summary, the combination of Se NPs and PS offers new opportunities for sustainable agricultural development, and its exploratory practice will greatly contribute to global agricultural progress.