Effect of GA3 plus Ethephon™ on glochid removal and cactus pear fruit quality

The market for cactus pear requires prior glochid removal; however, this process causes injury and damage to the fruit. The effect of growth regulators for pre-harvest removal of these small spines has been evaluated experimentally with promising results, to induce pre-harvest fall of glochids without damaging the fruit. In this study, the effectiveness of gibberellic acid (GA(3); 50 ppm) plus 2-chloroethane phosphonic acid (Ethephon (TM); 700 or 900 ppm) on glochid removal and the effects of the treatment on fruit quality in cactus pear cultivars 'Roja San Martin', 'Villanueva', and 'Roja Sangre de Cristo' were determined in a commercial plantation of cactus pear in the producing region of Puebla, Mexico. After anthesis, consecutive weekly applications of GA(3) in combination with Ethephon (TM) were made. The number and fall of glochids were evaluated, and fruit quality parameters were also assessed; weight loss of fruits stored at 25 degrees C for 14 days was also evaluated. Both treatments induced an elongation of around 65% in glochids; in general, 62-80% fall of glochids was also observed in harvested control fruits. The treatments, in general, caused a significant pre-harvest fall (PHF) of glochids. Besides, it was also observed that the glochids that remained on the treated fruits were easier to remove mechanically. Treated fruits of 'Roja San Martin' responded with the greatest total fall of glochids (97.8%), without significant differences between the two treatments. Fruit quality was slightly affected, positively or negatively, depending on the cultivar and treatment.