Abstract
A six parent dialled analysis was conducted to get basic information for improving yield of upland cotton. Heterosis, combining ability, genetic components and correlation coefficients for boll length, boll width, boll weight, 100 seed weight, lint weigth per boll and lint percentage were studied. Estimates of heterosis for all characters and heterobeltiosis for boll weight and lint weight per boll showed positive values. In general combining ability effect, 'Muan' and 'Imsung' showed highely positive effect in all characters. In specific combining ability effect, the combinations of 'Seungju${\times}$Imsung$.$Seosan${\times}$Imsung' for bll length, 'Cheju${\times}$Imsung$.$Seung${\times}$Imsung' for boll width, 'Cheju${\times}$Muan$.$Cheju${\times}$Imsung' for boll weight, 'Cheju${\times}$Soonchun$.$Muan${\times}$Imsung' for 100 seed weight, 'Soonchun${\times}$Muan' for lint weight per boll and 'Soonchun${\times}$Seosan$.$Seungju${\times}$Muan' for lint percentage showed highly positive effect. Partial dominance was observed for boll length, boll weight, 100 seed weight and lint weight per boll, complete dominance for boll width and overdominance for lint percentage. The number of effective gene group was estimated as one for all characters. The estimates of narrow and broad sense heritabilities were high for all characters except as one for all characters. The estimates of narrow and broad sense heritabilities were high for all characters except lint percentage. Correlation coefficients among the boll length, boll width, boll weight, 100 seed weight and lint weight per boll were positive, whereas lint percentage was negatively correlated with other characters.
