Search Results (5)

Sugar metabolism influences the quality of sweet corn (Zea mays var. saccharate Sturt) kernels, which is a major goal for maize breeding. In this study, the genome-wide transcriptomes from two supersweet corn cultivars (cv. Xuetian 7401 and Zhetian 11) with a nearly two-fold difference in kernel sugar content were carried out to explore the genes related to kernel sugar metabolism. In total, 45,748 differentially expressed genes (DEGs) in kernels and 596 DEGs in leaves were identified. PsbS, photosynthetic system II subunit S, showed two isoforms with different expression levels in leaf tissue between two cultivars, indicating that this gene might influence sugar accumulation in the kernel. On the other hand, hexokinases and beta-glucosidase genes involved in glycolysis, starch and sucrose metabolism were found in developing kernels with a genome-wide transcriptome analysis of developing kernels, which might contribute to the overaccumulation of water-soluble polysaccharides and an increase in the sweetness in the kernels of Xuetian 7401. These results indicated that kernel sugar accumulation in sweet corn might be influenced by both photosynthesis efficiency and the sugar metabolism rate. Our study supplied a new insight for breeding new cultivars with high sugar content and laid the foundation for exploring the regulatory mechanisms of kernel sugar content in corn. Full article

Multi-trait selection helps breeders identify genotypes that appeal to divergent groups of preferences. In this study, we performed simultaneous selection of sweet-waxy corn hybrids on several traits covering the perspectives of consumers (taller kernel depth, better eating quality), growers (early maturity, shorter plant stature, and high ear yield), and seed producers (high flowering synchrony, acceptable seed yield, and good plant architecture). Three supersweet corn lines and 8 waxy corn lines were intercrossed to generate 48 F1 hybrids according to North Carolina Design II, and these genotypes were laid out in a randomized complete block design with 3 replications across 2 seasons between 2017 and 2018. A sensory blind test on sweetness, stickiness, tenderness, and overall liking was conducted to assess the eating quality of steamed corn samples. Two methods of simultaneous selection, namely unweighted selection index and overall rank-sum index (ORSI), were applied to rank crosses, following all targeted groups of preferences. Genetic parameters and genetic gain were estimated to evaluate the effectiveness of those selection methods. Both approaches had similar patterns of preferable realized gain on each given trait and could identify similar top five crosses with only slight order changes, implying that these methods were effective to rank genotypes according to given selection criteria. One of the tested crosses, 101L/TSC-10 × KV/mon, consistently had the highest unweighted selection index in the dry (7.84) and the rainy (7.15) seasons and the lowest ORSI (310), becoming a promising candidate as synergistic sweet-waxy corn hybrid appealing to consumers, growers, and seed producers. The expected ideotypes of sweet-waxy corn hybrid are discussed. Full article

Three super-sweet corn hybrids (Zea mays L. convar. saccharata) with different ripening characteristics were grown in three water supplies (regularly irrigated, deficit-irrigated, and unirrigated) to examine the spectral reflectance at leaf and canopy levels, leaf area index (LAI) during the stage of development and their relationship with the yield and nutritional quality. Under unirrigated conditions, the plant’s height, diameter, and weight of ears per plants, as well as total carotenoid content of kernels, decreased, SPAD values of leaves, normalized vegetation differential index (NDVI) and LAI were low. The difference in SPAD and LAI was higher between the hybrids during the silking than the tasseling period under water deficiency. Under unirrigated dry conditions, no correlation was found between SPAD, NDVI, and yield. Using deficit irrigation, SPAD measured during tasseling correlated closely with the individual husked ear and the final yields as well as the sugar and carotene contents of kernels. Under this condition, NDVI did not correlate with the yield, but LAI was correlated with the yield and its carotene content. Under deficit irrigated conditions, the 46 to 49 range of SPAD measured during tasseling predicted 23.5 to 26.7 t ha⁻¹ depending on the hybrid, but this range predicted a yield lower by 6.4 to 10.1% during silking. Full article

The viability and vigor of crop seeds are crucial indicators for evaluating seed quality, and high-quality seeds can increase agricultural yield. The conventional methods for assessing seed viability are time consuming, destructive, and labor intensive. Therefore, a rapid and nondestructive technique for testing seed viability has great potential benefits for agriculture. In this study, single-kernel Fourier transform near-infrared (FT-NIR) spectroscopy with a wavelength range of 1000–2500 nm was used to distinguish viable and nonviable supersweet corn seeds. Various preprocessing algorithms coupled with partial least squares discriminant analysis (PLS-DA) were implemented to test the performance of classification models. The FT-NIR spectroscopy technique successfully differentiated viable seeds from seeds that were nonviable due to overheating or artificial aging. Correct classification rates for both heat-damaged kernels and artificially aged kernels reached 98.0%. The comprehensive model could also attain an accuracy of 98.7% when combining heat-damaged samples and artificially aged samples into one category. Overall, the FT-NIR technique with multivariate data analysis methods showed great potential capacity in rapidly and nondestructively detecting seed viability in supersweet corn. Full article

The flavor of sh2 super-sweet corn is preferred by consumers. Unfortunately, sh2 sweet corn has little genetic variation for insect resistance. In this paper we review the functions of two loci, p1 and a1. The P1 allele has a major role in sh2 sweet corn resistance to corn earworm, an allele that was lost in historical selection because of its pleiotropic effect on undesirable cob color and silk browning. The P1 allele has significant effects on biosyntheses of silk antibiotic compounds, maysin, apimaysin, methoxymaysin, and chlorogenic acid. The effect of a1 shows gene action for lowered maysin and significant epistatic action with p1. The dominant functional allele A1 causes anthocyanin pigments in aleurone, plant, and pericarp tissues; the recessive a1 allele causes absence of pigment in these tissues. If silk browning and cob color are critical factors for maysin production but lack the customer’s preference, then separating red cob and browning silk, which are controlled by the P1 allele, may be difficult if not impossible. One high silk maysin sh2 sweet corn germ­plasm, shrunken Zapalote Chico, has been released. There is some field corn germplasm with p1-wwr alleles, but the amount of antibiotic flavones and their potential as a donor need further investigation. Full article