Microenxertia in vitro de Opuntia spp, sobre porta-enxertos com diferentes níveis de ploidia

Abstract

The use of the micrografting technique between forage cactus cladodes can be considered a promising and relevant proposal for production systems, providing early provision of high quality vegetative material for planting. Another advantage is the use of combinations of clones and cultivars in the same plant. Enabling the exploration of the best characteristics of each of the grafted tissues. Example: Rootstocks tolerant to pests and diseases, reducing costs with the acquisition of cladodes and inputs such as pesticides. Therefore, the objective of this work was to evaluate the viability of in vitro micrografting of Opuntia spp. on rootstocks with different ploidy levels. To this end, homo and heterograftings were carried out using rootstocks and grafts from the in vitro cultivation of seeds of accessions 06 and 57, of the species of O. cochinellifera and O. undulata. The micrograftings were performed in an aseptic environment in a laminar flow chamber, without or with the use of ascorbic acid (1g/L). The grafts were obtained by making excisions of 0.5 cm from the apex of the donor cladodes, while the rootstocks measured 1cm. After 30 days of in vitro cultivation of the micrografted seedlings, characteristics of total length of the scion + rootstock, diameter in the grafting region, weight in mg of the scion + rootstock, number of shoots in the graft, number of roots in the graft, number of roots on the rootstock. The results for micrografts with the addition of ascorbic acid were not significant and were not statistically different from the micrografts without the addition of ascorbic acid. There were no significant differences for most of the variables analyzed, except the diameter in the grafting region. The homografts (06/06 and 57/57), horse and rider, had a larger diameter when compared to the heterografts. Heterografts showed healing and setting in a similar way to homografts, revealing compatibility between the species O. cochinellifera (2n = 2x = 22) and O. undulata (2n = 4x = 44) with different ploidy levels, which should be explored in seedling production in the genus Opuntia. In general, the presence of necrotic marks from tissue oxidation, occurring mainly in homografts without the addition of ascorbic acid, were not observed in homo or heterografts with the addition of the same, these presented uniform scars (space between grafts and rootstocks) in all treatments, resulting in a positive balance of four living individuals in the in vitro condition and one acclimatized.