Sweet Corn Lines Research Articles

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.

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.

Genetic variability for early seed vigor traits for enhanced performance under sub-optimum temperatures in sweet corn (Zea mays Convar. saccharata L.)

High germination and seed vigor under sub-optimum temperature is desirable for successful stand establishment in Sweet Corn. Aninvestigation was undertaken to assess the performance of shrunken2 based Sweet Corn hybrids; CMVL Sweet Corn-1 and Pusa SuperSweet Corn-2 and their parental lines; SWT16, SWT17, VSL16 and VSL4 for early seed vigor parameters under sub-optimum (15⁰C, 20⁰C)and optimum (25⁰C) temperature conditions. Among the genotypes, hybrids (CMVL Sweet Corn-1 and Pusa Super Sweet Corn-2) weresuperior than their parental lines for the seed vigor traits like seedling emergence, germination index, mean germination time (MGT),vigor indices, root growth parameters and field emergence under sub-optimum temperature. The inbred lines; SWT16 and SWT17had better performance than VSL16 and VSL4 for seed vigor parameters under sub-optimum temperatures. Seedling root architectureaffected seedling performance and establishment under sub-optimum conditions. In the study, under sub-optimum temperaturesseedling root parameters i.e. the root length, surface area and root volume reduced whereas the root diameter increased in the sweetcorn lines. Vigor index-II (0.87 and 0.78) and MGT (-0.87and -0.54) showed significant correlation with the field emergence of sweet corn genotypes under 15 and 20oC respectively and thus could be the selection indices for identifying sweet corn genotypes with optimum performance under sub-optimum temperature regimes.

Agronomic performance and genetic diversity of newly developed S4 temperate and tropical sweet corn lines

This study aims to evaluate agronomic traits and genetic diversity through correlation analysis, principal component analysis, and cluster analysis on 20 agronomic traits of 16 S4 tropical sweet corn lines (NG01-NGO16) and 4 S4 temperate lines (NGO17-NGO20) developed from varieties imported from Thailand, China, Japan, and the USA along with 3 inbred check lines viz., SW1 (sweet, yellow), D181 (sweet, white) and UV10 (sweet, purple). The field experiment was arranged in a randomised complete block design with 3 replicates in Hanoi, in the autumn-winter crop 2022 to evaluate twenty agronomic traits, divided into 4 groups viz., 5 growth traits, 7 morphological traits, 7 yield traits, and 1 quality trait. Correlation analysis showed that the single plant yield was positively correlated at p<0.01 with the number of kernels per row 0.61, the number of kernel rows per ear 0.57, and positively correlated at p<0.05 with ear diameter 0.47 and ear length 0.45. Twenty traits were dimensionally reduced to 3 main principal components contributing 66.8% of total phenotypic variation in which growth duration, plant height, ear height, leaf angle, number of kernels row per ear, number of kernels per row, 1000-grain weight, single plant yield and total soluble solids can be used to evaluate the differences of sweet corn lines. Cluster analysis based on principal components on 20 agronomic traits classified 20 sweetcorn lines into 3 main groups. This study provided useful information on phenotypic diversity and valuable sweetcorn genetic resources for breeding programs on speciality corn in Vietnam.

Transcriptome Analysis Identifies Novel Genes Associated with Low-Temperature Seed Germination in Sweet Corn.

Typically, sweet corn, particularly sh2 sweet corn, has low seed vigor owing to its high sugar and low starch content, which is a major problem in sweet corn production, particularly at low temperatures. There is considerable variation in the germination rates among sweet corn varieties under low-temperature conditions, and the underlying mechanisms behind this phenomenon remain unclear. In this study, we screened two inbred sweet corn lines (tolerant line L282 and sensitive line L693) differing in their low-temperature germination rates; while no difference was observed in their germination rates at normal temperatures. To identify the specifically induced genes influencing the germination capacity of sweet corn at low temperatures, a transcriptome analysis of the two lines was conducted at both normal and low temperatures. Compared to the lines at a normal temperature, 3926 and 1404 differently expressed genes (DEGs) were identified from L282 and L693, respectively, under low-temperature conditions. Of them, 830 DEGs were common DEGs (cDEGs) that were identified from both L282 and L693, which were majorly enriched in terms of microtubule-based processes, histone H3-K9 modification, single-organism cellular processes, and carbohydrate metabolic processes. In addition, 3096 special DEGs (sDEGs), with 2199 upregulated and 897 downregulated, were detected in the tolerant line L282, but not in the sensitive line L693. These sDEGs were primarily related to plasma membranes and oxygen-containing compounds. Furthermore, electric conductivity measurements demonstrated that the membrane of L282 experienced less damage, which is consistent with its strong tolerance at low temperatures. These results expand our understanding of the complex mechanisms involved in the cold germination of sweet corn and provide a set of candidate genes for further genetic analysis.

The impact of post-harvest storage on sweet corn aroma

Fresh market sweet corn ( Zea mays L .) is a high sugar, high moisture vegetable that, due to its fast metabolic rate, is susceptible to rapid post-harvest decay at ambient temperatures. Immediate cooling and storage at low but not freezing temperatures are well established industry practices for maintaining post-harvest sugar content. Less is known about how post-harvest storage temperature impacts other important sweet corn consumer traits, such as aroma. In this study we measure the production and stability of the cooked sweet corn aroma compounds dimethyl sulfide, dimethyl disulfide, dimethyl trisulfide, 3-methyl furan, 3-methyl butanal and 2-methyl butanal. We reveal that these aroma compounds are also susceptible to post-harvest decay if sweet corn is stored at ambient rather than cool temperatures. Furthermore, the quantities and post-harvest decay rates of aroma volatiles vary among different sweet corn lines, indicating that sweet corn genetics can impact maintenance of post-harvest flavor. Some aroma compunds found in cooked sweet corn. • Low temperature post-harvest storage maintains sugar content of sweet corn. • Post-harvest storage also impacts the stability of cooked sweet corn aroma. • Sweet corn varieties can have different aroma profiles and post-harvest stability. • Genetic factors exist to improve the flavor related shelf life of sweet corn.

A genome-wide association study of folates in sweet corn kernels.

Folate is commonly synthesized in natural plants and is an essential water-soluble vitamin of great importance inhuman health. Although the key genes involved in folate biosynthesis and transformation pathways have been identified in plants, the genetic architecture of folate in sweet corn kernels remain largely unclear. In this study, an association panel of 295 inbred lines of sweet corn was constructed. Six folate derivatives were quantified in sweet corn kernels at 20 days after pollination and a total of 95 loci were identified for eight folate traits using a genome-wide association study. A peak GWAS signal revealed that natural variation in ZmFCL, encoding a 5-formyltetrahydrofolate cyclo-ligase, accounted for 30.12% of phenotypic variation in 5-FTHF content. Further analysis revealed that two adjacent SNPs on the second exon resulting in an AA-to-GG in the gene and an Asn-to-Gly change in the protein could be the causative variant influencing 5-FTHF content. Meanwhile, 5-FTHF content was negatively correlated with ZmFCL expression levels in the population. These results extend our knowledge regarding the genetic basis of folate and provide molecular markers for the optimization of folate levels in sweet corn kernels.

Combining Ability and Testcross Performance for Carotenoid Content of S2 Super Sweet Corn Lines Derived from Temperate Germplasm

Understanding the impact of gene action and combining ability on targeted traits in a hybrid breeding program is imperative. The objective of this study was to estimate the genetic effect and combining ability of S2 super sweet corn lines on carotenoid content. Twenty S2 lines were crossed with two hybrid testers by using the line × tester mating design. Regarding parents, forty hybrids and two commercial checks were evaluated for carotenoid content across two different growing seasons between 2019 and 2020. The result indicated that the non-additive gene action governed the inheritance of carotenoid content. Several promising S2 lines for individual carotenoids were identified; only L20 possessed different and positive GCA values for all observed carotenoids. Moreover, genotype T2 was a promising tester to identify superior lines for creating biofortified sweet corn hybrids. Testcross hybrids with satisfactory performance, desirable SCA estimates, and involving at least one of the pairwise parents with positive and high GCA were successfully defined. Hybrid T2 × L20 had high lutein, zeaxanthin, β-cryptoxanthin, and total carotenoids contents (ranging from 12.58 to 74.01 µg/g of dry weight), whereas hybrid T2 × L9 showed the highest content of β-carotene (4.19 µg/g of dry weight). We propose that high GCA and line at least one of the pairwise parents be included in indirect selections for the hybrid breeding of high-carotenoid sweet corn.

Introgression of the RppQ gene from field corn improves southern rust resistance in sweet corn

Southern rust, one of the most destructive foliar diseases of sweet corn (Zea mays convar. saccharata var. rugosa), is caused by Puccinia polysora Underw. and leads to enormous yield losses and reduced quality of sweet corn in China. Utilization of resistance genes is an effective and environmentally friendly strategy for improving southern rust resistance of sweet corn. However, improvement is hampered by a lack of resistance genes in Chinese sweet corn germplasm. In this study, we introgress the southern rust resistance gene RppQ from Qi319, an inbred line of southern rust–resistant field corn, into four elite sweet corn inbred lines (1401, 1413, 1434, and 1445) using marker-assisted backcross breeding. These are parental inbred lines of four popular sweet corn varieties: Yuetian 28, Yuetian 13, Yuetian 26, and Yuetian 27. We developed five RppQ-based markers (M0607, M0801, M0903, M3301, and M3402) and employed these markers for foreground selection; 92.3 to 97.9% of the recurrent parent genomes were recovered following three or four rounds of backcrossing. The four newly developed sweet corn lines all showed significant improvement of southern rust resistance compared with their respective parent lines. Meanwhile, there was no significant difference in phenotypic data for agronomic traits. In addition, reconstituted hybrids derived from the converted lines retained resistance to southern rust, while other agronomic traits and sugar content remained unchanged. Our study provides an example of successful development of southern rust–resistant sweet corn using a resistance gene from field corn.

Studies on correlation and path co-efficient analysis of single cross hybrids in sweet corn

A total of 42 experimental hybrids generated by diallel mating design using 7 inbred lines of sweet corn were evaluated with parents and checks during Kharif 2019 at University of Agricultural Sciences, Dharwad. Green ear yield revealed a significant correlation in the positive direction with plant height, ear height, ear length, ear girth, number of kernel rows, and number of kernels per row at both genotypic and phenotypic levels, while a negative correlation was observed with days to 50% silking and Turcicum Leaf Blight. The highest value of correlation co-efficient for green ear yield was observed with green ear yield without husk, followed by the number of kernels per row and ear girth. However, there is no significant correlation between green ear yield and Total Soluble Solids. The genotypic correlation was found to be higher than the phenotypic correlation indicating high heritability of traits. Ear girth, ear height and the number of kernels per row displayed the highest positive direct effects on yield at the genotypic level and also manifested significantly positive indirect effects via plant height, ear height, green ear weight without husk, green fodder weight and the number of kernels per row. These three traits were likewise shown to have the most positive correlation with green ear yield. As a result, these attributes can be considered while selecting sweet corn genotypes for higher green ear yield.

Estimating the Breeding Potential of Purple Sweet Corn Lines with Topcross Mating Design

Estimating the Breeding Potential of Purple Sweet Corn Lines with Topcross Mating Design

Plant waterflow restrictions among sweet corn lines related to limited‐transpiration trait

AbstractWhile partial stomata closure under elevated vapor pressure deficit (VPD), that is, a limited‐transpiration trait resulting in soil water conservation and crop drought resiliency, has been identified in a few lines in all major crop species, the basis for the trait is not resolved. Since changes in stomatal aperture are associated with hydraulic processes, properties influencing waterflow in the plant are candidates associated with expression of limited‐transpiration. In a previous study with leaves of sweet corn (Zea mays L.), limited‐transpiration was only weakly associated with the effect of silver ion, an aquaporin inhibitor, on leaf transpiration rate. The hypothesis was explored that total aquaporin activity rather than only silver‐sensitive aquaporins may be more relevant in the expression of limited transpiration. Leaves were fed potent aquaporin inhibitors of mercury and peroxide which both resulted in greater transpiration inhibition than silver, but there were no differences in response among lines. A second hypothesis was that there may be a major limitation of waterflow in the root system accounting for genotypic variation in expression of the limited‐transpiration trait. No differences in root hydraulic conductance were found among sweet corn lines differing in the limited‐transpiration trait. However, it was discovered that the root conductance decreased during the photoperiod in all tested lines. Measurements of root hydraulic conductance in response to a silver treatment showed differences among lines with an association between the VPD breakpoint for limited transpiration and transpiration sensitivity to the silver treatment.

Changes on Sugar and Starch Contents during Seed Development of Synergistic Sweet Corn and Implication on Seed Quality

Synergistic sweet corn equipped with multiple-recessive genes encoding sugar synthesis is proposed through hybrid breeding to improve the balance eating quality including flavor, texture, and aroma. However, the drawback on seed quality occurs such as low germination and poor seedling vigor. This study aimed to investigate the changes of carbohydrate contents on seed quality of five sweet corn genotypes differing in the number of equipped recessive genes during seed development. Seeds were sampled at 4-day intervals from 18 to 46 days after pollination (DAP) and analyzed for seed germination, sugar, water-soluble polysaccharide, and starch. Then, their relationships were analyzed by using time series regression analysis. Although there were significant differences among 5 corn genotypes in their seed germination and carbohydrate contents, some genotypes showed responses in similar patterns. The optimal time to harvest seeds was genotype-dependent, which were 38 DAP for triple-recessive gene (btbtsh2sh2wxwx) and single-recessive genes (BtBtsh2sh2WxWx and Sh2Sh2susuWxWx) and 42 DAP for double-recessive genes (BtBtsh2sh2wxwx). The regression analysis revealed that seed germinability could be predicted by total starch content in synergistic sweet corn lines during seed development stages; however, this prediction seemed to be negligible in sweet corn genotypes equipped with a single-recessive gene. Implications and further suggestions for establishing an effective seed production technique and seed quality of synergistic sweet corn are discussed.

Combining ability and heterotic pattern in relation to F1 performance of tropical and temperate-adapted sweet corn lines

The aims of this study were: to assess the genetic relationship of supersweet corn populations; and to establish the heterotic pattern of 49 supersweet (sh2) corn inbreds on F2S5 generation based on molecular marker data and specific combining ability. Forty-nine inbreds were evaluated using 20 SSR molecular markers, which were allocated into heterotic groups according to the discriminant principal component analysis. Twelve inbreds were crossed in a complete diallel scheme. The 81 entries (hybrids developed, parental lines and three commercial checks) were evaluated in a triple partial balanced lattice design (9 × 9) during the growing seasons of 2016/2017 and 2017. The general combining ability (GCA) and specific combining ability (SCA) were estimated. The SCA values were used to set the heterotic patterns of the parental lines as well. Commercial yield without husk (CYWH) and ear length (EL) were more informative to set the heterotic groups. Additive and non-additive effects were important on the genetic control of the evaluated traits. However, for five of the six traits, the non-additive/dominance genetic effects showed to be more important in both environments. In fact, the hybrids developed among tropical by temperate germplasm had better performance than those ones developed within the temperate germplasm itself. SSR based-genetic distance demonstrate to be a reliable predictor as significant correlation was obtained between genetic distance with hybrid performance (for length of ears, ear height and CYWH) and SCA for all observed traits. The non-additive genetic effect that predominantly controlled all traits was the feasible explanation for the good prediction.

Limited‐transpiration rate and plant conductance in a diverse sweet corn population

AbstractLimited‐transpiration rate at elevated vapor pressure deficit (VPD) can allow soil water conservation for use during late‐season drought, but it can also result in decreased crop yields under well‐watered conditions because of restricted crop gas exchange. Previous studies with sweet corn (Zea mays L.) have found the limited‐transpiration rate was quite common among commercial cultivars even though sweet corn is commonly grown under well‐watered conditions. This study was undertaken to identify possible genetic sources of sweet corn that were not encumbered by the limited‐transpiration trait. Additionally, data were obtained to compare the plant hydraulic conductance among the lines. Among the 26 sweet corn lines included in this study, only eight did not express the limited‐transpiration trait. Four of the lines not expressing the limited‐transpiration (IL395a, IL543c, P39, and SD245) had stomata vapor conductance values over the range of tested VPD similar to the values expressed by many of the limited‐transpiration lines only at low VPD. The eight lines not expressing the limited‐transpiration trait tended to have low plant hydraulic conductance. For those lines expressing the limited‐transpiration trait, there was a correlation between the VPD at initiation of limited transpiration and plant hydraulic conductance. Expression of the limited‐transpiration traits proved, however, to be temperature sensitive in 7 of 18 tested lines expressing the trait at 32 °C because they failed to express the trait at 38 °C. The genetic variation in expression of the limited‐transpiration trait and plant hydraulic conductance identified in this study offers specific candidate inbred lines that could be used as genetic resources for improving sweet corn growth and yield for well‐watered environments.

Performance of Physiological Characteristics and Content of Sweet Corn Mutant Some Lines of Sugar (Zea mays L. saccharate Sturt.) Sied of Gamma Ray Irradiation in M1 Generation.

ABSTRACT Sweet corn has a multipurpose function. The need for this commodity continues to increase every year, while the sied of production produced by farmers have not been able to meet the needs. One effort to increase sweet corn production is by mutation techniques to assemble the genetic traits of varieties. This study aims to obtain the best interaction between sweet corn lines and gamma ray irradiation doses on physiological characteristics and sugar content in maniss corn plants (Zea mays L saccharata Sturt). This research was carried out in PT. Pertani, Sirnabaya Village, East Telukjambe sub District, Karawang start in May 2019 until September 2019. The method used is an experimental method using a factorial randomized block design. There are two factors consisting of 20 treatments. The first factor was the sweet corn with replications consisting of 5 lines, the second factor is the dose of gamma ray irradiation consisting of 4 levels. The effect of the treatment was analyzed by analysis of variance, to find out the best treatment continued with the DMRT (Duncan Multiple Range Test) test at 5% level. There was the best interaction between sweet corn lines and gamma ray irradiation dose, the best effect was on G1M1 treatment in almost all parameters of observation (plant height, number of leaves, weight of cobs with hurt, weight of cobs without hurt, long of cobs with hurt, long of cobs without hurt, diameter of cobs with hurt, diameter of cobs without hurt, sugar content, leaf area, leaf area index, crop yields). Keywords : lines, sweet corn, gamma ray irradiation, sugar content

THE EFFECT OF LIQUID ORGANIC FERTILIZER CONCENTRATION ON GROWTH AND RESULS OF VARIOUS SWEET CORN LINES IN MARGINAL LAND USING A DRIP IRRIGATION SYSTEM

Utilization of the potential of marginal land with adequate water and nutrients is an important factor in increasing corn production. However, high porosity levels and low nutrient levels cause growth and production of corn is not optimal. The aim of this research is to obtain an irrigation technique combined with efficient fertilization in the sweet corn cultivation system in marginal land. The field research was carried out at Faculty of Agricultural Research Wedomartani, Depok Sleman Yogyakarta. The study was conducted from September 2019 to February 2020. The research aims to get best sweet corn line at various concentrations of liquid organic fertilizer in marginal land with a drip irrigation system.The research was arranged in a completely randomized design (CRD) with 3 replications. The first factor is sweet corn lines, which consists of 9 levels, namely, G1 (5042B), G2 (KD-11), G3 (KD-13), G4 (SB-11), G5 (SB-13), G6 (SB-14), G7 (SB-16), G8 (SB-21), and G9 (SB-22). While the second factor is the irrigation system combined with fertilization (fertigation) which consists of 3 levels, namely the drip irrigation system with a concentration of liquid supplement fertilizer 2 cc / L, 3 cc / L and 4 cc / L. The results showed that the drip fertigation system with a concentration of POC 3 cc / L was able to give a better effect on plant height and leaf length in sweet corn. SB / 1-3 lines was the best lines as prospective parents for making hybrid lines for plant height, leaf length, number of leaves and cob length.Keywords: lines, liquid organic fertilizer, sweet corn, marginal land, irrigation system

Development and Selection of Purple Sweet Corn Inbred Lines

The aim of this study was to developed purple sweet corn inbred lines from a cross between purple waxy corn and white sweet corn in Vietnam. Twenty elite inbred lines were top crossed with two testers in Spring season 2020 to estimate the general combining ability. Nine lines with Brix > 16, thin pericarp 100mg/100g can be classified as super sweet purple sweet corn lines. Five lines had high GCA regarding marketable yield (UV10, UV24, UV40, UV46, UV71), two lines has high GCA on Brix (UV12, UV16), and five lines had high GCA on anthocyanin content (UV35, UV36, UV38, UV46, UV73). Taken together, UV10 and UV12 lines are super sweet purple sweet corn lines and have high GCA for marketable yield and quality, respectively. This is the first report on the development and selection of purple sweet corn inbred lines in Vietnam.

Combining Ability Analysis in Sweet Corn (Zea Mays Saccharrata L.) Using Line by Tester Design

Aim The purpose of this study was to investigate the different combination of testcrosses for morphological and yield relating traits and to investigate general combining ability of the inbred lines. Materials and Methods This research was conducted at The University of Agriculture Peshawar, Pakistan during 2016. Line x-tester analysis was used to test general combining ability (GCA) effects of 24 S4 lines of sweet corn. Alpha lattice design with two replications and two checks was used during the experiment. Research data were recorded on various flowering, morphological and yield parameters. Results Highly significant variations were recorded among the testcrosses for the studied traits except anthesis silking interval (ASI), 100-kernel weight. Minimum days to tasseling (48-days) and silking (53.5-days) was exhibited by pop-syn-swt (9-4)×synthetic sweet. GCA effect was -2.14 for tasseling and -2.00 for silking. Maximum value (3.5-days) for ASI was recorded for Pop-synswt 1(8-3)×synthetic sweet, while GCA effect for ASI was -0.71. Lowest plant height (129.8 cm) was recorded for pop-syn-swt 1(3-3)×synthetic sweet, while GCA effect for plant height was observed to be -14.79. Maximum cob length (16.6 cm) was revealed by pop-syn-swt 1(12-2)×synthetic sweet. For cob length GCA effect of 1.01 was recorded. Maximum 100 kernel weight (31.3 g) was estimated for pop-syn-swt 1(2-1)×synthetic sweet. GCA effect of 1.85 was recorded for 100-kernel weight. Highest mean (7143.9 kg ha-1) for grain yield was recorded for pop-syn-swt 1(9-4)×synthetic sweet. GCA effect for grain yield was found to be 1370.93. Conclusion Generally a low GCA value, either positive or negative indicates that the mean of a parent does not largely vary from its offsprings. In contrast, high GCA value suggests that parent is either superior or inferior to the general mean and it has high heritability and less environmental effects. Based on the findings in this research, the above mentioned testcrosses can be included in future sweet corn breeding programs where early flowering and yield attributes is desired.

Combining ability assessment of agronomic characteristics of 8 inbred sweet corn lines

This study was conducted to evaluate 28 sweet corn hybrid combinations to determine the combination ability of 8 lines of sweet corn inbred (K60, R111, N1, N4, N5, N7, N8 and N12) of a S8generation. The results showed that the yield of hybrid combinations was in a range of 14.2 to 23.7 tons/ha. Especially, the hybrid combination THL9 had a yield of 23.7 tons/ha, reached the soluble solids content of 13.9%. Meanwhile, the yield of the hybrid combination THL14 reached 21.4 tons/ha and its soluble solids content reached 13.6%. This result was higher than Golden Cob which was the control variable in this study, and had a yield of 17.4 tons/ha and a soluble solids content of 12.2%.Evaluating the combining ability of the yield and total soluble solids content of 8 lines of sweet corn showed that the N4 lines had a higher combining ability than the other lines in terms of fresh corn yield and total soluble solids content. R111 line and N4 line could combine good productivity (ˆSij: 2,433∗) and total soluble solids content (ˆSij reached 0.963∗)