GENETIC-VARIATION IN APICAL DOMINANCE OF CEDRELA-ODORATA SEEDLINGS IN RESPONSE TO DECAPITATION

Authors: NEWTON, A.C., CORNELIUS, J.P., MESEN, J.F. and LEAKEY, R.R.B.

Journal: SILVAE GENETICA

Volume: 44

Issue: 2-3

Pages: 146-150

ISSN: 0037-5349

Source: Web of Science (Lite)

Genetic variation in apical dominance of Cedrela odorata seedlings in response to decapitation.

Authors: Newton, A., Cornelius, J.P., Mesen, J.F. and Leakey, R.R.B.

Journal: Silvae Genetica

Volume: 44

Pages: 146-150

ISSN: 0037-5349

Abstract:

An assessment was made of genetic variation in apical dominance of Cedrela odorata L. using a decapitation test. Nineteen weeks after sowing, pot-grown seedlings belonging to 30 open-pollinated progenies from 5 provenances were decapitated by removal of the shoot apex, leaving shoots of a uniform height of 20 cm. Foliage was reduced to a single leaf with 2 pairs of leaflets on each plant. The length and number of lateral shoots subsequently formed were measured at 2 weeks, 4 weeks and 8 weeks after decapitation to determine the percentage bud activity and dominance ratio of the shoots. Percentage bud activity increased within the first 2 weeks to 4 weeks and declined thereafter as dominance was reimposed. Significant differences between provenances and progenies were recorded both in the timing and extent of peak bud activity (P < 0.001, ANOVA). Maximum bud activity ranged from 17.7% to 24.2% in the 5 provenances whereas mean values for the progenies differed by more than a factor of 2, ranging from 13.6% to 32.3%. Pronounced genetic variation in dominance ratio was also recorded; maximum values occurred 4 weeks after decapitation in all progenies. Dominance ratio was negatively correlated with percentage bud activity (r = 0.65, P < 0.001). These results indicate that significant potential exists for selection of Cedrela odorata genotypes with relatively high apical dominance, which may exhibit superior form and pest tolerance.

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Source: Manual

Preferred by: Adrian Newton