INDUCCIÓN DE PARTENOCARPIA EN Opuntia spp.

Abstract

La tuna (Opuntia spp.) es un fruto que posee cualidades apreciadas por los consumidores en México y otros países; sin embargo, algunas personas no la consumen porque tiene numerosas semillas grandes en la pulpa, lo cual afecta su calidad y limita su aceptación en los mercados. El objetivo de esta investigación fue determinar la factibilidad de producir frutos partenocárpicos de calidad en cuatro variedades de nopal tunero de amplio uso por los agricultores de Zacatecas y San Luis Potosí. Se aplicaron las dosis de 0, 50, 100 y 200 ppm de ácido giberélico (AG3) a flores emasculadas en etapa de pre-antesis de las variedades Amarilla Montesa (Opuntia megacantha Salm-Dick), Burrona (Opuntia albicarpa Sheinvar), Cristalina (Opuntia albicarpa Sheinvar) y Rojo Pelón (Opuntia ficus-indica L.). A las flores testigos (0 ppm) se les dejó polinizar libremente. El diseño experimental fue completamente al azar, con 16 tratamientos resultantes de un arreglo factorial completo con dos factores y cuatro niveles para cada factor (24). La unidad experimental estuvo conformada por una flor. Las aplicaciones se hicieron en 20 flores (repeticiones) de diferentes plantas por tratamiento. Se obtuvieron frutos partenocárpicos con las tres dosis de AG3, con una reducción significativa de su longitud, diámetro y peso. Los frutos con aplicación de AG3 redujeron peso de pulpa, relación pulpa/peso de fruto y grados Brix (ºBx) de la pulpa y de la cáscara; además se incrementó el grosor de la cáscara en comparación con los frutos provenientes de flores sin tratar (testigo). Aunque los frutos partenocárpicos contaban con poca pulpa y cáscara gruesa, esta última presentó lecturas de ºBx similares a las de la pulpa, por lo que la cáscara es potencialmente comestible.

Parthenocarpic Cactus Pears (Opuntia spp.) with Edible Sweet Peel and Long Shelf Life

“…Our results confirm that the response to hormonal induction of parthenocarpy in Opuntia depends on the genotype, as pointed out by Varela et al [19] and Montalt et al [27]. The characteristics of parthenocarpic tunas produced by CP-30 Red and CP-40 Yellow are better than those reported to date by different researchers.…”

“…The characteristics of parthenocarpic tunas produced by CP-30 Red and CP-40 Yellow are better than those reported to date by different researchers. [19,25,36], such as small size, low weight, low pulp production, low solids content [35], or large and hard SR [25,40] that detract from their attractiveness for human consumption. The parthenocarpic fruits of the CP-30 Red and CP-40 Yellow genotypes obtained over three years show that the present results obtained with this method of parthenocarpy induction were effective in producing pulp without troublesome SR.…”

“…The pulp of the cactus pear originates from the dorsal epidermal cells of the funicular sheath covering the ovule [14], which requires the stimulation of ovule fertilization [18]. Per capita consumption of tunas in Mexico has not grown significantly in recent years [19], and one of the causes is the refusal of consumers to swallow the seeds, which are between 200 and 400 per fruit [10,11], with a hardened cover, popularly called bones [14]. To break this cover requires pressures of 0.2 to 4.6 kN [20,21] so chewing them would put the teeth at risk, and to avoid this, the consumer chooses to swallow them with the pulp.…”

“…To break this cover requires pressures of 0.2 to 4.6 kN [20,21] so chewing them would put the teeth at risk, and to avoid this, the consumer chooses to swallow them with the pulp. This causes some people to avoid the consumption of cactus pears and consider them inappropriate for small children [10,19,22]. Tuna seeds are of two types, normal and abortive; normal seeds are 4.5 mm long, 3.5 mm wide, and 1.6 mm thick, on average, while abortive seeds are smaller [21].…”

“…The first studies on hormone induction were those of Trippi and del Frari [33], who tested different doses of naphthaleneacetic acid applied to open flowers of O. ficus-indica but did not prevent seed formation. Subsequently, gibberellic acid (GA 3 ) was applied to flowers at anthesis [34] or to emasculated flower buds at pre-anthesis [19,35,36], and even combining AG 3 with other growth regulators [25], but without achieving the expected success because the fruits presented important defects such as reduced size and weight, little pulp, and insipid, relatively large, and hard seed residues. In some cases, repeated applications of growth regulators were evaluated to increase fruit size without achieving seedless-quality fruit.…”