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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.

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Improved maize populations and cross hybrids can be beneficial alternatives for commercial single-cross hybrids and good elite sources for diverse inbred lines. A set of 22 genotypes comprised 10 population crosses, 10 top crosses, and two check cultivars were evaluated at Cereal Crop Research Institute, Pirsabak-Nowshera, in a randomized complete block design with three replicates in 2014. This research's major aims were to determine the magnitude of heterosis and the degree of character association between yield and its attributes to select superior genotypes from the breeding material. Data were recorded on maturity, and yield associated traits, where significant genetic variability was observed among the genotypes for all the studied traits except days to silking. Mean values for the studied traits ranged from 44 to 52 days for tasseling, 48 to 54 days for anthesis, 49 to 54 days for silking, -1.33 to 2.33 for the anthesis-silking interval, 2.53 to 8.47 kg for fresh ear weight, 12 to 16 rows for kernel rows cob-1, 27.15 to 37.49 g for 100-kernel weight and 2830 to 7649 kg ha-1 for grain yield. Days to silking, anthesis silking interval, and kernel rows cob-1 showed low broad sense heritability (12.08%, 24.84%, 27.59%), days to tasseling, days to anthesis revealed moderate heritability (40.53%, 36.62%), while fresh ear, 100-kernel weight, and grain yield exhibited high broad-sense heritability (94.89%, 82.33%, 90%). Negative and significant heterotic values were observed for maturity traits, while heterotic values were positive and significant for yield-associated traits. Correlation analysis revealed that characters like fresh ear weight (r = 0.93) and 100-kernel weight (r = 0.50) manifested a strong positive and significant association with grain yield. Based on mean performance and grain yield, promising hybrids were 3008F3 x 2007-WC and 3008F3 x 2010. The current study revealed significant genetic variability among the tested hybrids; hence, it can be used in future breeding programs to produce early maturing and high-yielding maize hybrids.Days to tasseling, genetic variability, heterosis, population cross, top cross Keywords: HBV, HCV, ICT, PCR, Risk factors, Mansehra