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• Background and Aims Silicon (Si) has been shown to ameliorate the negative influence of cadmium (Cd) on plant growth and development. However, the mechanism of this phenomenon is not fully understood. Here we describe the effect of Si on growth, and uptake and subcellular distribution of Cd in maize plants in relation to the development of root tissues. • Methods Young maize plants (Zea mays) were cultivated for 10 d hydroponically with 5 or 50 µM Cd and/or 5 Si. Growth parameters and the concentrations of Cd and Si were determined in root and shoot by atomic absorption spectrometry or inductively coupled plasma mass spectroscopy. The development of apoplasmic barriers (Casparian bands and suberin lamellae) and vascular tissues in roots were analysed, and the influence of Si on apoplasmic and symplasmic distribution of ¹⁰⁹Cd applied at 34 nM was investigated between root and shoot. • Key Results Si stimulated the growth of young maize plants exposed to Cd and influenced the development of Casparian bands and suberin lamellae as well as vascular tissues in root. Si did not affect the distribution of apoplasmic and symplasmic Cd in maize roots, but considerably decreased symplasmic and increased apoplasmic concentration of Cd in maize shoots. • Conclusions Differences in Cd uptake of roots and shoots are probably related to the development of apoplasmic barriers and maturation of vascular tissues in roots. Alleviation of Cd toxicity by Si might be attributed to enhanced binding of Cd to the apoplasmic fraction in maize shoots.

Adoption of cover crops has the potential to increase agricultural sustainability in the US and beyond. In 2017, a survey was conducted with Nebraska stakeholders in an attempt to evaluate current cover crop management strategies adopted in soybean (Glycine max [L.] Merr.), field corn (Zea mays L.), and seed corn production. Eighty-two Nebraska stakeholders answered the survey, of which 80% identified themselves as growers. Eighty-seven percent of respondents manage cover crops, and the average cover crop ha planted on a per farm basis is 32%. The primary method of establishing cover crops following soybeans and field corn is drilling. In seed corn, interseeding is the main seeding strategy for cover crop establishment. Cereal rye (Secale cereale L.) appeared as the most adopted cover crop species (either alone or in mixtures with radish [Raphanus sativus L.] or hairy vetch [Vicia villosa Roth]). Over 95% of respondents utilize herbicides for cover crop termination in the spring before crop planting. Glyphosate is used by 100% of survey respondents that use herbicides for cover crop termination. The major observed impacts of incorporating cover crops into a production system according to survey respondents are reduced soil erosion and weed suppression. According to 93% of respondents, cover crops improve weed control by suppressing winter and/or summer annual weed species. The biggest challenge reported by cover crop adopters is planting and establishing a decent stand before winter. According to the results of this survey, there are different management strategies, positive outcomes, and challenges that accompany cover crop adoption in Nebraska. These results will help growers, agronomists, and researchers better guide cover crop adoption, management, and future research and education needs in Nebraska and beyond.

Termination of an existing failed corn stand before replanting is essential. Two studies were conducted in Stoneville and Verona, MS, from 2020 to 2021 to evaluate timing of corn or soybean replanting following different herbicide treatments applied to simulated failed stands of corn. Treatments included paraquat alone at 841 g ai ha −1 , paraquat at 841 g ha −1 + metribuzin at 211 g ai ha −1 , and clethodim at 51 g ai ha −1 + glyphosate at 1,121 g ae ha −1 applied at the V2 growth stage. Replant timings were 1 and 7 d after herbicide treatment (DAT). Pooled across replant timings, paraquat + metribuzin provided the greatest control 3 DAT compared with other treatments in both studies. At 14 and 21 DAT, clethodim + glyphosate controlled more corn than did paraquat + metribuzin and paraquat alone. Control of a simulated failed corn stand with paraquat alone never exceeded 50% at 3 to 21 DAT. Soybean yield in all plots receiving herbicide treatment targeting simulated failed corn stands were similar and ≥2,150 kg ha −1 . When applied at the V2 corn growth stage, both clethodim + glyphosate and paraquat + metribuzin controlled a simulated failed stand of corn. This study demonstrated the importance of terminating failed stands of corn before replanting because of dramatic reductions in yield in the plots not treated with herbicide.

Rice black-streaked dwarf virus (RBSDV) causes maize rough dwarf disease (MRDD), which is a viral disease that significantly affects maize yields worldwide. Plants tolerate stress through transcriptional reprogramming at the alternative splicing (AS), transcriptional, and fusion gene (FG) levels. However, it is unclear whether and how AS and FG interfere with transcriptional reprogramming in MRDD. In this study, we performed global profiling of AS and FG on maize response to RBSDV and compared it with transcriptional changes. There are approximately 1.43 to 2.25 AS events per gene in maize infected with RBSDV. GRMZM2G438622 was only detected in four AS modes (A3SS, A5SS, RI, and SE), whereas GRMZM2G059392 showed downregulated expression and four AS events. A total of 106 and 176 FGs were detected at two time points, respectively, including six differentially expressed genes and five differentially spliced genes. The gene GRMZM2G076798 was the only FG that occurred at two time points and was involved in two FG events. Among these, 104 GOs were enriched, indicating that nodulin-, disease resistance-, and chloroplastic-related genes respond to RBSDV stress in maize. These results provide new insights into the mechanisms underlying post-transcriptional and transcriptional regulation of maize response to RBSDV stress.

 Two field experiments were conducted to evaluate the effect of tillage, crop residues and crop rotation on productivity of clover, maize and mung bean, at the experimental research station of the College of Agricultural Engineering Sciences - University of Baghdad in Aljadriya, Baghdad – Iraq during two seasons of 2021-2022. 1st trail was with two factors: residues (0%R and 100%R) and tillage (minimum (MT) and conventional (CT)) with four replicates. Results indicated the best values of height and dry matter yield were (70.25 cm and 5.558 Mg ha-1) for (100%R+MT) compared with (65.5 cm and 4.985 Mg ha-1) for (0%R+CT) respectively. The 2nd trail was with three factors: the same tillage and residues coupled with crop rotations (clover-maize) and (clover-mung bean). Results (representing the accumulated effect of both trials) indicated the best values of height, dry matter yield and grains and seeds  yield were (236.25 and 111.5) cm, (4.560 and 14.745) Mg ha-1, (6.840 and 3.754) Mg ha-1 for (100%R+MT) treatment compared to (210.0 and 101.25) cm, (4.048 and 11.337) Mg ha-1, (5.685 and 2.829) Mg ha-1 with (0%R+CT) for maize and mung bean respectively and under crop rotations (clover-maize) for maize and (clover- mung bean) for mung bean.

This study was aimed to identification of certain crosses to produce hybrids with higher performance per se can be aided by the determination of simple sequence repeats (SSR), which can improve our understanding of the genetic divergence of maize lines and their classification into different heterotic groups. Variability for each locus was measured using the polymorphism information content (PIC), with an average of 0.55, suggesting that the markers were highly informative. Analysis of the molecular variance (AMOVA) indicated higher divergence among the maize lines, suggesting the existence of different groups. The unweighted pair group method with arithmetic mean analysis (UPGMA) and the three-dimensional principal coordinate analysis (PCoA) revealed seven heterotic groups. Therefore, knowledge on the genetic diversity distribution in these maize inbred lines is essential to determine strategies to exploit heterosis in breeding programs in future studies.

We compared the relationship between grain yield per plant (YP) and shoot biomass per plant (SP) in three annual crops with contrasting reproductive strategies: sunflower, a determinate species with a single inflorescence; maize, a determinate species with a limited capacity to adjust the number of ears in response to resource availability; and indeterminate soybean, a species with a large capacity to adjust the number of inflorescences. Our working hypotheses were: H1—the relationship between YPandSP is linear; H2—the intercept of the model is zero, i.e. there is not a threshold plant mass for reproduction. A wide range of YPand SPwas generated by manipulation of plant density;SPvaried between 0.3 and 196g per plant in soybean, between 6 and 873g per plant in sunflower and between 23 and 697g per plant in maize. Within these broad ranges of plant size, both hypotheses were rejected in five out of six experiments, i.e. the relationship between YPand SPdeparted from linearity and there was a threshold for SPbelow which no grain set occurred. TheSP threshold for grain set varied widely among species; it was close to 2g per plant for soybean, 27g per plant for sunflower and 43–71g per plant for maize. Because of this size threshold and non-linearity, harvest index (HI=YPSP−1) was stable for mid-size plants, diminished slightly for large plants, and diminished sharply for smaller plants in all three crops. Harvest index stability was highest in soybean, intermediate in sunflower and lowest in maize. Differential stability of reproductive partitioning partially derived from contrasting patterns of meristem allocation.

Using local resources and minimizing environmental impacts are two important components of sustainable agriculture. Meat and bone meal (MBM), tankage, is a locally produced organic fertilizer. This study was conducted to investigate the response of sweet corn (Zea mays L. var. saccharata Stuart.) and soil water nitrate (NO3-N) concentration to MBM application at two locations, Waimānalo and Poamoho, on the island of O’ahu. The objectives were to determine effects of six application rates (0, 112, 224, 336, 448 and 672 kg N ha−1) and two application timings (preplant and split application) on: (1) sweet corn growth, yield, and quality, and (2) soil water nitrate concentration within and below the root zone. The split-plot was designed as four replicates randomly arranged in a complete block. Plant growth of roots and shoots, yield, and relative leaf chlorophyll content of sweet corn increased with increasing application rates of MBM in both locations. At Poamoho, yield was 13.6% greater in preplant versus split application. Nitrate-nitrogen losses were reduced by 20% at Waimānalo and 40% at Poamoho when MBM was applied in split applications. These findings suggest that MBM is an effective nitrogen source for sweet corn and a split application of MBM may reduce the potential for pollution.

THIS STudy was aimed to induce genetic variation toward drought tolerance after treatment with EMS as a mutagen to two maize inbred lines and their single hybrid. The experiment was carried out at Abo-Ghraib Research Station, Baghdad during the spring season of 2019. The experiment included three irrigation intervals 7, 9 and 11, four concentrations of EMS (0, 50, 60, and 70 mM) and three maize genotypes distributed in three replications using randomized complete block design (RCBD) with split-split plot arrangement which included three irrigation intervals 7, 9 and 11 days occupied the main plot, while the sub plots included three maize genotypes, and four EMS concentrations which were distributed in sub-sub plots. Results were revealed significant differences among EMS treatments and irrigation interval treatments. The inbred line 5 in control treatment showed a significant increase in days for both anthesis and silking (70.11 and 71.94) days, respectively. Plants of Nahrain hybrid also showed a super performance in plant height, leaf area, and number of rows ear-1, with a mean of 154.47cm, 746.31cm2 and 17.83 row ear-1, respectively. The irrigation intervals of 9 and 11 days were significantly decreased the mean performance of genotypes, compared to the shortest irrigation interval (7 days) which had highest mean in most traits. None treated plants (0 mM EMS) had a significant effect on the performance of most studied traits, except the anthesis and silking time, which gave the highest values under the concentration 60 mM with 69.11 and 70.48 days, respectively. Hybrid plants interacted significantly with the EMS concentration of 0 mM producing the maximal means of plant height and leaf area (169.56cm and 759.78cm2 respectively). On the other hand, the hybrid was significantly interacted with the shortest irrigation interval in the mean traits of plant's height and leaf area (163.50 cm and 757 cm2, respectively). The triple interaction between hybrids, shortest irrigation interval and EMS concentration of 60 mM had significantly increased leaf area reached 769.67cm2, meanwhile the triple interaction between hybrid plants, shortest irrigation interval, and the EMS concentration of 0 mM recorded the highest value of plant yield (199.67g). It can be concluded from the current study that the genotypes differed in their response to 9 and 11 days irrigation intervals, with a negative effect of the later interval on the vegetative and yield traits of maize compared with shorter irrigation interval.

Popcorn, one of the most popular snack foods in the world, is known for being a high fiber, healthy food. Our research has found that commercial popcorn also contains significant amounts of the class of antioxidants known as phenolic acids. The total antioxidant capacity of raw and popped popcorn extract has been quantified using the Folin–Ciocalteu and FRAP assays. The polyphenols were found exclusively in the pericarp of the kernel completely bound to the oligosaccharide fiber matrix. An in vitro digestion study was also performed to predict the phenolic acids’ bioavailability. On average, nine commercial popcorn samples contain 5.93 ± 0.92 mg/g of total polyphenols after alkaline hydrolysis and 2.66 ± 0.15 mg/g after in vitro digestion as measured by the Folin–Ciocalteu assay. Furthermore, the popping process was found not to significantly decrease the antioxidant capacity. These results indicate that a considerable amount of the bound polyphenols are bioaccessible. Due to the high levels of bioaccessible polyphenols, popcorn may be a significant source of dietary polyphenol antioxidants.