The Effects of Gibberellic Acid and Emasculation Treatments on Seed and Fruit Production in the Prickly Pear (Opuntia ficus-indica (L.) Mill.) cv. “Gialla”

Abstract

Prickly pear (Opuntia ficus-indica (L.) Mill. 1768) is cultivated in several dry and semi-dry areas of the world to produce fresh fruit, bioenergy, cosmetics, medicine, and forage. One of the main production constraints is the presence of many seeds within the fruit, which can negatively influence both the fresh-fruit market price and industrial transformation processes. In this study, different gibberellic acid (GA3) concentrations were tested for their ability to produce well-formed and seedless fruits. Different application methods (injection and spraying) and concentrations of GA3 (0, 100, 200, 250, and 500 ppm) combined with floral-bud emasculation were applied to a commercial plantation in southern Italy to evaluate their effects on the weight, length, and diameter of the fruits, total seed number, hard-coated viable seed number, and seed weight per fruit. The results indicated that the application of 500 ppm GA3 sprayed on emasculated floral buds was the most effective method for reducing seed numbers of prickly pear fruits (−46.0%). The injection method resulted in a very low number of seeds (−50.7%) but produced unmarketable fruit. Observed trends suggest the need to investigate the impact of higher GA3 concentrations and the applicability of a maximum threshold. Further studies are needed to increase our understanding of the physiological effects of the gibberellic acid pathway through productive tissue in terms of organoleptic and fruit quality.

Effect of Exogenous Application of Gibberellic Acid (GA3) on Seed Size and Fruit Quality of Prickly Pear Cactus (Opuntia ficus-indica)

“…No significant difference in fruit weight and peel weight was found between control and 100 ppm (96.8, 92.31 and 39.69, 40.51 g, respectively) in the first season, while lower fruit weight and peel weight were detected using the 500 ppm treatment (61.97, 34.28 g, respectively). Similar results were reported by Mejia and Cantwell, Neji et al, and Marini et al ,, …”

“…The lowest seed number in class B was in 500 ppm GA3 with values 18.73, 27.27, and 24.53 in the first, second, and third seasons, respectively. Similar results were reported by Mejia and Cantwell, Neji et al, and Marini et al 4,30,31 In seed class C, there were significant differences between the three treatments. The highest number was observed on 100 ppm treatment ( 70 The different letters (in the same column) represent statistically significant differences between treatments (p < 0.05).…”

Horticultural Crop Response to Different Environmental and Nutritional Stress

“…The effect of environment conditions (temperature, rainfall, altitude, soil types, hail) [5][6][7][8][9], nutritional strategies [5,6,[10][11][12][13][14], water (stress, salinity) [5,8,12,15], container substrate of cultivation [16] on yield, yield traits and quality were analyzed in different crops in an open field [8,9,13,14,17] and greenhouses [5][6][7][10][11][12]15,16].…”

“…Different innovative strategies were presented that included protected structures, container type, cultivation techniques [5,10,16], symbiotic relationships [6,7], fertigation strategies [10] new agricultural management technologies (remote sensing, smartphone) [11] novel hybrids for breeding [12] spraying of Gibberellic acid [17], water supplies [8,15] and substrate [16] cover crops management [13] and stand reduction [9].…”

“…The author tested the application of two methods (injection and spraying) of gibberellic acid (GA 3 ) on the prickly pear cactus both at pre-and post-blooming in order to obtain well-formed seedless fruits in emasculated flowers [17]. The experiments were conducted in the Apulia region, Italy.…”