Transgressive Segregation and the Nature of Gene Action for Yield in an Intervarietal Cross of Upland Cotton1
- A. M. El-Adl and
- P. A. Miller2
Two inbred parental lines, their F1, and six inbred lines selected for high yield after three cycles of recurrent selection in this population were evaluated at three locations for two years. The F2 yielded 32.6% more than the midparent value and exceeded the higher parent by 13.3%. The F1 also exceeded the midparent values for several components of yield, including lint percentage, weight per boll, number of bolls per plot, lint index, and seed index.
The mean yield of the six selected lines exceeded that of the F1 by 5.5%. Each of the six lines was higher in lint yield and lint percentage than the higher parent of the original cross, which indicated that transgressive segregation for these traits had occurred
Fifteen possible crosses among the six lines were compared with the above entries at three locations in the second year. These hybrids averaged 9.6% higher in yield than the mean of their parents. Significant heterosis was also detected for lint percentage, weight per boll, number of seed per boll, and lint index.
Estimates of general combining ability from the set of diallel crosses were significant for all traits except lint percentage, which demonstrated the importance of additive genetic effects for those traits. The variance for specific combining ability was significant only for lint percentage.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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