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Study of drought stress correlation on yield and yield components of maize cultivars (Zea mays L.)
67-73Views:187This article was investigated to study the correlation and analysis of drought stress regression on maize cultivars' yield and components. The variance analysis results showed a significant difference between drought stress levels in terms of plant height, total dry weight and number of seeds per row, the total weight of cob, grain yield, harvest index, stem diameter, and cob weight with protective leave. Also, there was a significant difference in ear weight without protective leaves, ear diameter, ear length, plant weight, 100-seed weight, and seed per ear on hybrid treatments. There were statistically significant differences between cultivars in plant height, leaf area, ear diameter, ear length, number of seeds per row, number of seeds per ear, the total weight of cob wood, 100-seed weight, harvest index, plant dry weight. The results of the correlation of traits for the mean levels of drought stress showed a positive and significant correlation between plant yield and plant height, seed per row, ear length and weight of 5 pieces of wood and also with a total weight of cob wood, ear weight with bark showed the highest correlation. There is a significant correlation between leaf area and stem diameter, plant weight, total dry weight at the probability level of 0.05. Correlation coefficients between traits in non-stress conditions showed a positive and significant correlation between grain yield and height, ear length and grain in the row, which was a significant increase compared to stress conditions. The correlation of traits under full stress conditions also showed that the correlation coefficient between cob length trait and positive height was positive and significant. From the study of correlation coefficients between maize traits in non-stress conditions, it can be concluded that the most important components of grain yield are cob length and grain per row. While the correlation coefficients under moisture stress conditions show that the grain trait in the row has a positive and significant correlation with yield, under stress conditions in the cob stage did not show any traits with correlation yield.
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Inheritance of Plant and Ear Height in Maize (Zea Mays L.)
34-38Views:412Plant and ear height are very important characters not only for describing new varieties of maize (Zea mays L.), but for green and dry matter production, and even for grain yield. Significant positive correlations have been reported by various authors between plant height and stover yield, plant height and dry matter yield, and plant height and grain yield. The height of the main ear is also correlated to plant height. It depends on the variety or the environment, but is likely to be the same height within a population. Many environmental and agronomical factors (e.g. plant density, fertilization, pests and diseases) influence the expression of these characters, which are not quality traits. Their expression is controlled by many genes and by the interactions between these genes. The heritability of these traits is high and they show significant genotypic variability and positive heterosis, as reported in many research publications.
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Investigation of combining ability and superiority percentages for yield and some related traits in yellow maize using line × tester analysis
5-14Views:242Combining ability estimation is an important genetic attribute for maize breeders in anticipating improvement in productivity via hybridization and selection. This research was carried out to investigate the genetic structure of the 27 F1 maize hybrids established from nine lines derived from Maize Research Department and three testers, to determine general combining ability (GCA), determine crosses showing specific combining ability (SCA) and superiority percentages for crosses. Nine lines, three testers, 27 F1 hybrids and two check commercial hybrids (SC162 and SC168) were studied in randomized complete block Design (RCBD) with three replications during 2016. The results of mean squares showed that significant and highly significant for most studied traits (days to 50% tasseling, days to 50% silking, plant and ear height, ear position, ear length, no. of kernels per row, 100-kernel weight and Grain yield). Estimates of variance due to GCA and SCA and their ratio revealed predominantly non-additive gene effects for all studied traits. Lines with the best GCA effects were: P2 (line 11) and P6 (line 21) for grain yield, for testers Gm174 and Gm1021 had significant GCA effects for grain yield. The hybrids P5×Gm1021, P6×Gm1021, P7×Gm1021, P8×Gm1002, P9×Gm1002 had significant and negative SCA effects for grain yield. Crosses P1×Gm174, P2×Gm1002, P5×Gm1021, P6×Gm174, P6×Gm1021, P7×Gm1021, P8×Gm1002, P9×Gm1021 were the best combinations manifested and significant superiority percentages over than check varieties (SC162 and SC168) for most studied traits. Therefore, these hybrids may be preferred for hybrid crop development.
Abbreviations: GCA general combining ability; SCA specific combining ability
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Investigation of directions of crossing in maize (Zea mays L.)
43-48Views:97In Hungary, we examined eight features of twelve direct cross hybrids over a period of three years. The twelve hybrids were derived from direct and reciprocal crosses of four parental lines. We did not find significant differences in the cases of stalk diameter and leaf number in the average of 3 years in any of the hybrids. Statistically explainable differences in primary branches were observed in hybrids UDH5 and UDH8 and also in UDH6 and UDH11. It was evident in both instances that degrees of heterosis in reciprocal crosses far exceeded those of direct ones. High tassel branch number was dominant over the low one; consequently, parents with higher tassel numbers enforced their effects during the formation of this trait in hybrids. We experienced positive correlation (r=0.67**) between plant height and main ear height. A positive correlation (r=0.89**) was also found between the tassel length of the main axis above the lowest and the upper side branch. We observed a medium correlation (r=-0.42**) between the number of primary lateral branches and plant height. The number of primary lateral branches showed the highest heterosis. These results can be utilized in practical selection and seed production.