Heterosis and Combining Ability in Intraspecific and Interspecific Crosses of Cotton1
- A. Marani2
Trials were conducted in 1961 and 1962 on seven and eight varieties, respectively, of G. hirsutum L. and G. barbadense L. and all possible reciprocal crosses between them. The average magnitude of heterosis for lint yield was 24.5% and 21.6% in the intraspecific crosses of G. Oirsutum L. and G. barbadense L., respectively, and 72.8% in the interspecific crosses. Heterosis for lint yield was associated in all cases with heterosis for yield of seedcottou and in many cases also for the number of bolls per m2. Heterosis for boll-weight was found only in G. hirsutum L. intraspecific crosses where it was associated with heterosis for seed-index, lint-index, and number of seeds per boll. The interspecific crosses had a low lintpercent because heterosis for seed-index was much more pronounced than heterosis for lint-index in these crosses.
Effects of general combining ability in the interspecific crosses, which were more pronounced than effects of specific combining ability, corresponded to the performance of the parental varieties themselves. If heterosis in interspecific crosses is to be used to breed F1 hybrids, the selection of parental varieties should be made on the basis of their own performance for those traits that have shown consistent and significant effects of general combining ability.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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