In a range of defoliation of fully expanded leaves of 0, 10, 50 or 75% imposed weekly or biweekly until uncipient flowering in 3 indigenous Ethipoian mustard (Brassica carinata A. Braun) selections, optimum leaf yield of 27, 40, and 55 T ha-1 for `Mulio Giant`, `CRRS 2` and `CRRS 5` in that order, was attained at 50% defoliation regardless of leaf harvest frequency. Tendency towards late flowering increased with amount of defoliation and was manifest particularly in the early `Mulio Giant`. Seed yield, highest in `Mulio Giant`, was least influenced by defoliation regime. A 10% defoliation increased seed yield under weekly and biweekly defoliationin CRRS 5 and `CRRS 2` respectively, and a concomitant seed yield reduction occured in each cv as defoliation increased at either harvest frequenies. Seed Harvest Index was highest in `Mulio Giant` and was independent of defoliation intensity for all cvs. Results are discussed with reference to variability among cvs in compensatory growth under an altered canopy structure. [AS]
