Sweet Corn Hybrids Research Articles

Enrichment of Vitamin A and Vitamin E in Sweet Corn Kernels Through Genomics-Assisted Introgression of Mutant Version of crtRB1 and vte4 Genes.

Recessive shrunken2 (sh2)-based sweet corn is preferred worldwide as it possesses higher sugar and extended shelf life. However, traditional sh2-based sweet corn is poor in vitamin A and vitamin E. Here, parental lines of two sh2-based sweet corn hybrids, viz. PSSC-2 and ASKH-2, were targeted for introgression of β-carotene hydroxylase 1 (crtRB1) and γ-tocopherol methyltransferase (vte4) genes through marker-assisted backcross breeding. Seeds with sh2sh2sh2 genotype in the endosperm were selected based on the shrunken phenotype in BC1F1, BC2F1 and BC2F2 generations. Gene-based markers, viz. 3'-TE-InDel and 118-InDel specific for crtRB1 and vte4, respectively, were successfully utilized for foreground selection in BC1F1, BC2F1 and BC2F2. Reconstituted hybrids showed high provitamin A (proA: 19.52 ± 0.52µg/g) with a maximum of 7.8-fold increase over original hybrids (ASKH-2 and PSSC-2: 3.33 ± 0.28µg/g). High α-tocopherol (20.75 ± 0.44µg/g) and α/γ-tocopherol ratio (0.55 ± 0.02) with an average enhancement of 2.3- and 1.7-fold, respectively, was recorded among reconstituted hybrids over original versions (α-tocopherol: 9.21 ± 0.33µg/g, α/γ-tocopherol ratio: 0.31 ± 0.01). The average yield of reconstituted hybrids (11.40 ± 0.22 t/ha) was at par with the original sweetcorn hybrids (11.60 ± 0.20 t/ha). This is the first report of stacking sh2, crtRB1 and vte4 genes to improve nutritional quality in sweet corn. These biofortified sweet corn hybrids hold immense significance to alleviate micronutrient malnutrition.

The sugary enhancer1 (se1) Allele Is Associated with Significant Decreases in Carotenoids and Tocotrienols in Yellow (Y1) sugary1 (su1) Sweet Corn

A distinctive phenotype of homozygous sugary enhancer1 (se1) sweet corn (Zea mays) inbreds and hybrids is a light-yellow color in mature kernels. Carotenoid pigments contribute to yellow endosperm color in maize and are of nutritional importance in the human diet along with the related tocochromanols, the E vitamins. Tocochromanols, including both tocopherols and tocotrienols, are antioxidants important in human nutrition and cardiovascular health. Effects of the presence of sugary enhancer1 allele on carotenoid and tocochromanol levels in homozygous su1, Y1 endosperm were evaluated in the Wisconsin Sweet Corn Diversity Panel. Although population structure was present in the panel, the majority of variation in carotenoid levels was explained by genotype at the se1 locus. se1 was associated with significant decreases in the amount of lutein (34%) and zeaxanthin (36%) and decreases of tocotrienols by 12% to 65%. There were no significant differences in β-carotene and tocopherol levels between the two groups. Given that the biosynthesis pathways for carotenoids and tocochromanols are well defined, these differences in carotenoids and tocotrienols between su1Se1 and su1se1 inbreds point to a broader role of se1 alleles in metabolic pathways beyond endosperm starch production.

BIOLOGICAL AND ECOLOGICAL STATE OF COMMON SMUT (USTILAGO ZEAE) IN CORN SILAGE FIELDS IN THE KYZYLORDA REGION AND MEASURES TO COMBAT IT

Corn, as one of the most important grain feed crops, is of great importance in increasing gross grain yields. Corn smut (Ustilago zeae) can also cause large economic losses in susceptible sweet corn hybrids. Protection against this pathogen is mainly based on prevention. To date, many corn smut control methods have been recommended or evaluated, including crop rotation, sanitation, seed treatments, fertility modification, and biological control. Despite these frequently cited control strategies, host resistance appears to be the only effective control method for common smut in areas where Ustilago zeae is common. The purpose of the study is to study the resistance to smut against a natural infectious background of samples from a collection of corn from breeding nurseries in Kazakhstan. Based on the results of a study of the resistance of a corn collection to bladder smut against a natural infectious background, varieties were identified on whose plants symptoms of the disease were not detected: Altay 250 MV, Budan 237 MV, Tatty-2012 and Tayelsizdik-20 SV. The identified samples also had high productivity and grain yield. A high level of heritability (Hb2 – 0.85) of the disease susceptibility index among the studied samples was revealed.

Planting Geometry May Be Used to Optimize Plant Density and Yields without Changing Yield Potential per Plant in Sweet Corn.

Planting geometry is one of the most important management practices that determine plant growth and yield of corn. The effects of eight planting geometries (35 × 23 cm, 40 × 21 cm, 45 × 19 cm, 50 × 18 cm, 55 × 17 cm, 60 × 16 cm, 65 × 15 cm, 70 × 15 cm) on plant growth and yields of three sweet corn hybrids (Argos F1, Challenger F1, Khan F1) were investigated under Erzurum, Türkiye conditions in 2022 and 2023 years. Variance analysis of the main factors shows a highly significant effect on whole traits but in two-way interactions some of the traits were significant and in the three-way interactions, it was insignificant. As an average of years, the number of plants per hectare at the harvest varied between 92,307 (35 × 23 cm) and 120,444 (70 × 15 cm) according to the planting geometries. The highest marketable ear number per hectare (107,456), marketable ear yield (24,887 kg ha-1), and fresh kernel yield (19,493 kg ha-1) were obtained from the 40 × 21 cm planting geometry. The results showed that the variety Khan F1 grown at 40 × 21 cm planting geometry obtained the highest marketable ear number (112,472), marketable ear yield (29,788 kg ha-1), and fresh kernel yield (22,432 kg ha-1). The plant density was positively correlated with marketable ear number (r = 0.904 **), marketable ear yield (r = 0.853 **), and fresh kernel yield (r = 0.801 **). The differences among the varieties were significant for the studied traits, except for plant density and kernel number per ear. In conclusion, the variety Khan F1 should be grown at the 40 × 21 cm planting geometry to maximize yields under study area conditions without water and nutrient limitations.

Effects of Hybrids, Foliar Treatments, and Infection Conditions on Bacterial Leaf Streak of Sweet Corn.

Bacterial leaf streak (BLS) of corn caused by Xanthomonas vasicola pv. vasculorum was first reported in the United States in 2017. The biology and management of BLS are poorly understood. The objective of this work was to determine the effects of hybrids, foliar treatments, and infection conditions (timing, temperature, and inoculation site) on BLS of sweet corn. Field studies were conducted to determine if hybrid or foliar disease management treatments influenced BLS development and yield. Corn leaves were inoculated in plots with X. vasicola pv. vasculorum, and noninoculated plots were used for comparison. The leaf incidence and severity of BLS differed significantly among sweet corn hybrids, suggesting different levels of susceptibility to BLS. Grain yield was significantly reduced (14.7%) by BLS for one hybrid. The corn growth stage at the time of infection influenced BLS, with incidence and severity significantly greater after inoculation at stage V6 than at V9. Foliar application of Kocide, LifeGard, and Kocide and LifeGard significantly reduced leaf severity compared with nontreated controls in field studies. Kocide significantly reduced leaf incidence, but no treatments significantly increased yield versus controls. In comparisons of inoculation methods in a growth chamber, lesion length on leaves was significantly greater on stalk-inoculated than leaf-inoculated plants. Lesions developed on leaf-inoculated plants only at inoculation sites, whereas lesions developed on stalk-inoculated plants on multiple leaves. In controlled environments, lesion length on leaves was significantly greater at 21°C than at 27 and 32°C. This study expands our understanding of factors that influence the development and management of BLS of sweet corn.

Alteration of stress-physiological mechanisms in sRNA-treated sweet corn plants during MDMV infection.

Maize dwarf mosaic virus (MDMV) can significantly reduce the growth and development of susceptible varieties of sweet corn. The virus utilises the energy and reserve sources of plant cells to ensure its reproduction in the microspaces formed by cell membranes. Therefore, the severity of stress can be monitored by examining certain physiological changes, for example, changes in the degree of membrane damage caused by lipid peroxidation, as well as changes in the amount of photosynthetic pigments. The activation of antioxidant enzymes (e.g. ascorbate peroxidase, guaiacol peroxidase, glutathione reductase) and the accumulation of phenolic compounds with antioxidant properties can indirectly protect against the oxidative stress caused by the presence of the positive orientation, single-stranded RNA-virus. This study demonstrates the changes in these physiological processes in a sweet corn hybrid (Zea mays cv. saccharata var. Honey Koern.) susceptible to MDMV infection, and suggests that exogenous small RNA treatment can mitigate the damage caused by virus infection.

Grain Yield and Its Contributing Traits in Sweet Corn Hybrids

Grain Yield and Its Contributing Traits in Sweet Corn Hybrids

Analysis of nutritional composition in opaque2- and crtRB1-based single- and double-biofortified super sweet corn.

Sweet corn has emerged as a favorite food item worldwide owing to its kernel sweetness. However, traditional sweet corn cultivars are poor in provitamin-A (proA) and essential amino acids, viz., lysine and tryptophan. So far, no sweet corn hybrid with high nutritional qualities has been commercialized elsewhere. Here, we analyzed accumulation of provitamin-A (proA), lysine, and tryptophan in a set of mutant versions of (i) crtRB1-, (ii) o2-, and (iii) crtRB1 + o2-based sweet corn inbreds and hybrids with (iv) traditional sweet corn (wild-type: O2 + CrtRB1). The crtRB1- and crtRB1 + o2-based genotypes possessed significantly higher proA (17.31ppm) over traditional sweet corn (2.83ppm), while o2- and crtRB1 + o2-based genotypes possessed significantly higher lysine (0.345%) and tryptophan (0.080%) over traditional sweet corn (lysine 0.169%, tryptophan 0.036%). Late sowing favored high kernel lysine, proA, and green cob yield among hybrids. Sweetness (17.87%) among the improved inbreds and hybrids was comparable to the original sweetcorn genotypes (17.84%). Among the four genotypic classes, crtRB1 + o2-based improved genotypes showed stronger association among traits over genotypes with o2 and crtRB1 genes alone. Significant association was observed among (i) proA and BC (r = 0.99), (ii) proA and BCX (r = 0.93), (iii) lysine and tryptophan (r = 0.99), and (iv) green cob yield with fodder yield (r = 0.73) in sweet corn hybrids. The study demonstrated that combining crtRB1 and o2 genes did not pose any negative impact on nutritional, yield, and agronomic performance. Sweet corn with crtRB1 + o2 assumes significance for alleviating malnutrition through sustainable and cost-effective approach.

Unlocking a Mystery: Characterizing the First Appearance of Clavibacter nebraskensis in Mexican Cornfields.

The Goss's wilt and leaf blight is a disease of maize (Zea mays) caused by Clavibacter nebraskensis, which was widespread in the last several years throughout the Midwest in the United States, south in Texas, and north to Canada. The bacterium is included within the high-risk list of quarantine pathogens by many plant protection organizations and countries including Mexico. Severe blight symptoms on maize plants were found in different provinces from Coahuila and Tlaxcala, Mexico, in 2012 and 2021, respectively. Twenty bacterial isolates with morphology similar to C. nebraskensis were obtained from the diseased maize leaves. The isolates were confirmed by phenotypic tests and 16S rRNA and gyrB sequencing. Two strains were tested for pathogenicity tests on seven hybrid sweet corn cultivars available in Mexico, and the most sensitive cultivar was tested for all the strains to fulfill Koch's postulates. The phylogenetic reconstruction based on two single loci reveals a remarkable clustering of Mexican strains to American strains reported approximately 50 years ago. The presence of this pathogen represents a risk and a significant challenge for plant protection strategies in Mexico and maize diversity.

Utilizing genomic prediction to boost hybrid performance in a sweet corn breeding program.

Sweet corn breeding programs, like field corn, focus on the development of elite inbred lines to produce commercial hybrids. For this reason, genomic selection models can help the in silico prediction of hybrid crosses from the elite lines, which is hypothesized to improve the test cross scheme, leading to higher genetic gain in a breeding program. This study aimed to explore the potential of implementing genomic selection in a sweet corn breeding program through hybrid prediction in a within-site across-year and across-site framework. A total of 506 hybrids were evaluated in six environments (California, Florida, and Wisconsin, in the years 2020 and 2021). A total of 20 traits from three different groups were measured (plant-, ear-, and flavor-related traits) across the six environments. Eight statistical models were considered for prediction, as the combination of two genomic prediction models (GBLUP and RKHS) with two different kernels (additive and additive + dominance), and in a single- and multi-trait framework. Also, three different cross-validation schemes were tested (CV1, CV0, and CV00). The different models were then compared based on the correlation between the estimated breeding values/total genetic values and phenotypic measurements. Overall, heritabilities and correlations varied among the traits. The models implemented showed good accuracies for trait prediction. The GBLUP implementation outperformed RKHS in all cross-validation schemes and models. Models with additive plus dominance kernels presented a slight improvement over the models with only additive kernels for some of the models examined. In addition, models for within-site across-year and across-site performed better in the CV0 than the CV00 scheme, on average. Hence, GBLUP should be considered as a standard model for sweet corn hybrid prediction. In addition, we found that the implementation of genomic prediction in a sweet corn breeding program presented reliable results, which can improve the testcross stage by identifying the top candidates that will reach advanced field-testing stages.

Selection of Sweet Corn Inbred Lines by Agronomic Performance to Determining Hybrid Parents

The development of hybrid sweet corn varieties involves the selection of parental lines with specific traits to ensure good yield potential. The selection of inbred lines of sweet corn is a critical aspect of breeding programs aimed at developing improved varieties. This research will provide useful information of sweet corn inbreed lines have the potential to be developed as parent lines in the development of hybrid varieties. The study utilized 24 inbred lines (G1-G24) of sweet corn and employed a Randomized Complete Block Design (RCBD). Data analysis involved the use of analysis of variance with a 5% significance level, path and dendrogram analysis. Based on the analysis of 24 inbreed line of sweet corn, the potential for selecting parents based on quantitative traits influencing the outcome is evident in inbreed line G18, G12, G4, G23, and G20. Identification of these potential parents is essential for the genetic improvement of the population. The correlation heatmap data indicates a 41% correlation between the number of rows and cob stag length, and correlation between number of rows and ear diameter by 48%. The path diagram indicates that fresh weight, a crucial measure of crop yield, is strongly influenced by several agronomic traits, including plant height, ear length, ear diameter, dry weight, number of plants, row length, brix, and ear stalk. G24 can indeed be used as one of the parents with other group in hybrid breeding programs.

Digital Image Analysis of Low-Temperature Responses in Sweet Corn Hybrid Seedlings

Breeding for stress-tolerant hybrids begins with screening germplasm for tolerant genotypes. We employed a non-destructive and objective method to evaluate the low-temperature response of sweet corns at the seedling stage, using a digital image analysis. It was estimated using summed leaf area, a new parameter defined as the sum of the leaf area measured from images taken at different angles. The summed leaf area, SPAD, shoot and root fresh weight, and total root length were significantly different among hybrids. The group mean of sugary endosperm type was significantly higher than that of shrunken type for all traits but SPAD. For the summed leaf area, the top three ranked hybrids were from the sugary type, but the area for the following three hybrids from the shrunken type did not differ from that for the first three hybrids. The summed leaf area was correlated with SPAD (r = 0.49 **), shoot (r = 0.99 **) and root (r = 0.93 **) fresh weight, and total root length (r = 0.76 **). Phytoglycogen in seeds only had a significant correlation (r = 0.46 **) with the area. The summed leaf area of only one hybrid differed between normal- and low-temperature conditions. The low-temperature response based on the summed leaf area was reflected in the field condition, with a few exceptions. The results suggest that the summed leaf area via digital image analysis can be used to evaluate low-temperature response in sweet corns.

Grain yield and its contributing traits in promising sweetcorn hybrids

AbstractThe augmentation of domestic sweetcorn (Zea mays L. saccharata) production in semiarid regions necessitates the development of new superior hybrids with high yield potential. This study aimed to identify the most influential characteristics contributing to sweetcorn grain yield in these regions. Nineteen promising sweetcorn hybrids and the commercial hybrid KSC403su as the control were examined using a randomized complete block design with three replications in a 2‐year study (2021–2022) at the Khorasan Razavi Agricultural and Natural Resources Research and Education Institute Center (ARREO) in Mashhad, Iran. The combined analysis of variance revealed significant variances attributed to genotype (G) for all studied traits, while year (Y) and G × Y effects were significant for most characteristics. Phenotypic correlations indicated a highly significant association of grain yield with grain depth (r = 0.79, p < 0.01), kernel number per row (r = 0.75, p < 0.01), row number per ear (r = 0.63, p < 0.01), ear length (r = 0.58, p < 0.01), and ear diameter (r = 0.57, p < 0.01) traits. Path analysis results emphasized the critical role of traits such as grain depth, row number per ear, and ear length, showcasing a highly significant positive direct impact on grain yield and also a significantly positive association with grain yield. In this study, hybrids PSM3, PSM4, PSM9, PSM16, and PSM19 exhibited the highest values for grain yield and yield‐contributing traits, suggesting their potential for further research in multiple locations with varying environmental conditions before being recommended to farmers.

Unveiling the sweetness: evaluating yield and quality attributes of early generation sweet corn (Zea mays subsp. sachharata) inbred lines through morphological, biochemical and marker-based approaches.

Sweet corn is gaining tremendous demand worldwide due to urbanization and changing consumer preferences. However, genetic improvement in this crop is being limited by narrow genetic base and other undesirable agronomic traits that hinder the development of superior cultivars. The main requirement in this direction is the development of potentially promising parental lines. One of the most important strategies in this direction is to develop such lines from hybrid-oriented source germplasm which may provide diverse base material with desirable biochemical and agro-morphological attributes. The study was undertaken to carry out morphological and biochemical evaluation of 80 early generation inbred lines (S2) of sweet corn that were developed from a cross between two single cross sweet corn hybrids (Mithas and Sugar-75). Moreover, validation of favourable recessive alleles for sugar content was carried out using SSR markers. The 80 sweet corn inbreds evaluated for phenotypic characterization showed wide range of variability with respect to different traits studied. The highest content of total carotenoids was found in the inbred S27 (34μgg-1) followed by the inbred S65 (31.1μgg-1). The highest content for total sugars was found in S60 (8.54%) followed by S14 (8.34%). Molecular characterization of 80 inbred lines led to the identification of seven inbreds viz., S21, S28, S47, S48, S49, S53, and S54, carrying the alleles specific to the sugary gene (su1) with respect to the markers umc2061 and bnlg1937. Comparing the results of scatter plot for biochemical and morphological traits, it was revealed that inbreds S9, S23, S27 and S36 contain high levels of total sugars and total carotenoids along with moderate values for amylose and yield attributing traits. The inbred lines identified with desirable biochemical and agro-morphological attributes in the study could be utilized as source of favourable alleles in sweet corn breeding programmes after further validation for disease resistance and other agronomic traits. Consequently, the study will not only enhance the genetic base of sweet corn germplasm but also has the potential to develop high-yielding hybrids with improved quality. The inbreds possessing su1 gene on the basis of umc2061 and bnlg1937 markers were also found to possess high sugar content. This indicates the potential of these lines as desirable candidates for breeding programs aimed at improving sweet corn yield and quality. These findings also demonstrate the effectiveness of the molecular markers in facilitating marker-assisted selection for important traits in sweet corn breeding.

Phenological, growth, and yield responses of sweet corn to elevational air temperatures in the humid tropics

Temperature plays a determinant role in the rate of plant metabolic activities and, accordingly, dictates the plant's phenological stages, growth, and productivity. The objective of this study was to evaluate the phenological, growth, and ear yield behavior of ten sweet corn hybrids in response to elevational temperature changes in the humid tropics. Seeds of ten hybrids were grown in three elevations (coastland, midland, and highland). Results show that the hybrids belonged to the same maturity group with comparable accumulated growing degree days, but they varied in green ear yield, harvest index, and heat use efficiency. It was also found that higher elevations lead to longer plant growth and fewer growing degree-day requirements, resulting in increased in biomass accumulation for ear and overall vegetative growth but more efficient in the heat use. These findings will be useful as a guide for crop management scheduling, including fertilizers application, pest control, diseases control, and weed control, to maximize sweet corn yield at different elevations in the humid tropics.

Appropriate selection of organic hybrid sweet corn varieties can positively influence both the effectiveness of the insect biological control agent Beauveria bassiana and fungal disease resistance

Appropriate selection of organic hybrid sweet corn varieties can positively influence both the effectiveness of the insect biological control agent Beauveria bassiana and fungal disease resistance

Stability yield indices on different sweet corn hybrids based on AMMI analysis.

Currently, sweet corn is considered an important crop due to its high sugar content and low starch content. Important sugars in sweet corn include sucrose, fructose, glucose, and maltose. The purpose of the present study was to use the yield indices of the eight examined sweet corn hybrids and the correlation of the yield indices together. Concentration is important for consumers in terms of yield indices. The research site was located at the Látókép Experimental Station of the University of Debrecen. The small plot experiment had a strip plot design with four replications. The previous crop was sweet corn; the plant density was 64 thousand/ha. The obtained result indicates that Biplot AMMI based on IPCA1 showed that the DB, NO, GS, and GB hybrids had stability and high performance in terms of yield indices. At the same time, fructose and glucose had stable parameters for the hybrids involved in the study. IPCA1 AMMI biplot showed that the ME hybrid had stability and high performance in terms of iron and zinc as well. IPCA2 AMMI biplot showed that DE, GB, and GS hybrids had stability and the highest performance on yield parameters in the scope of the research. Fructose, glucose, and sucrose had stable parameters on hybrids based on IPCA2. The DB and SE hybrids had desirable performance in Lutein and Zeaxanthin based on the biplot. The DE hybrid had a maximum performance on iron and zinc parameters.

Evaluation of growing of sweet maize varieties and hybrids as a repeated crop in different planting periods and schemes

In a comprehensive scientific study conducted in the Bukhara province, the cultivation of 12 varieties and hybrids of sweet (vegetable) corn was undertaken as a repeated crop in medium-saline meadow alluvial soils. Noteworthy varieties and hybrids evaluated in the study included "Zamin," "Mazza," "Megaton F1," and "Union F1," selected based on their suitability for the specific soil and climate conditions prevalent in the province. The research aimed to discern the optimal combinations of planting schemes and periods for maximizing yield in sweet corn production. Among the diverse planting schemes and periods tested, the study highlighted the effectiveness of the 60x30 and 70x25 cm schemes, identifying them as the optimal choices. Furthermore, the optimal planting period was pinpointed to be July 5, emphasizing the significance of timing in sweet corn cultivation in the region. The findings indicated that when varieties and hybrids like "Zamin," "Mazza," "Megaton F1," and "Union F1" were planted on July 5 using the 60x30 and 70x25 cm schemes, an impressive yield of 10.1-14.4 tons of vegetable cobs per hectare was achieved. This underscores the importance of meticulous selection of both planting schemes and periods to optimize sweet corn production in the specific agro-climatic conditions of the Bukhara province. The research outcomes contribute valuable insights for local farmers and agricultural practitioners, offering practical recommendations for enhancing crop productivity and ensuring sustainable sweet corn cultivation practices.

Cultivation of vegetable (sweet) corn varieties and hybrids as repeated crops in Bukhara

Cultivation of vegetable (sweet) corn varieties and hybrids as repeated crops in Bukhara

استجابة الذرة الحلوة للأسمدة الحيوية البكتيرية والرش بالمغذيات المعدنية

This study was aimed to investigate response of two sweet corn hybrids to bacterial biofertilizers and spraying with Mg+2 and Ca+2 and their impact on the Yield during Spring season 2022, CASH seeds (H1) and ROI SOLEIL seeds (H2) were planted in pots, when they reached 2-3 leaves treated with four treatments which included without biofertilizer (B0), with Azospirillum brasilense (B1) with Pseudomonas fluorescens (B2) and the interaction with Azospirillum brasilense and Pseudomonas fluorescens (B3) then transferrd to the field, and sprayed the seedling after 20 and 30 days of seedling with three concentrations which included control, without spraying (N0), spraying with Mg++ and Ca++ with concentration of 25 mg L-1 (N1) and 50 mg L-1 each elements (N2), The experiment was carried out according to RCBD with in split plot arrangement. The results showed that hybrid H2, the treatment of bacterial biofertilizers B3 and the foliar spraying of Magnesium and Calcium N2 had significant effect in all studied traits. H2B3N1 had significant effect in plant height and the number of leaves, H2B3N2 had significant effect in leaf area and leaf area index and plant dry weight, H2B1N2 had significant effect in total chlorophyll concentration in leaves, It was found that the study factors and their interactions had a role in increasing the vegetative growth indicators of the sweet corn hybrids.