Abstract
Grafting is an alternative method for the early production of Araucaria angustifolia seeds, and welding quality is essential for the success of the technique. The objective of this study was to create a classification of welding quality to estimate the percentage of scion survival. The patch and flute grafting techniques were used in a greenhouse and in the field. Survival was evaluated 270 days after grafting (DAG). At 60 DAG, observations of the graft connection region were made with the naked eye, classifying the connections into four welding classes. After 160 DAG, transverse cuts were performed on each class and visually and anatomically evaluated. Flute grafting presented higher initial survival (79%), but at 180 DAG, the survival rate of both techniques was similar (48% for flute and 41% for patch). There was greater scion survival for the class that had only two regions in contact with discontinuity in the bark. Stabilization of survival occurred after 180 DAG, regardless of the welding class. Visually, there were differences in welding quality; however, anatomically, all classes presented vascular connections. The visual welding quality assessment underestimated the percentage of scion survival. However, the vascular connection and development of parenchymatous tissue are promising for diagnosing grafting success.
Highlights
Araucaria angustifolia (Bertol.) Kuntze (Araucariaceae), popularly known as Araucaria, Brazilian pine, or Paraná pine, is native to Brazil and found in the mixed ombrophilous forest (Carvalho, 2003)
For percentages of survival for A. angustifolia grafts, we found significant differences between grafting techniques in the first evaluation (60 days after grafting (DAG)) only, with 79.6% survival of the flute grafting (Table 1)
When we compared the evaluation times of each grafting technique used, we found that the greatest survival occurred at 60 DAG for flute grafting and that after this period, there was a decline in survival
Summary
Araucaria angustifolia (Bertol.) Kuntze (Araucariaceae), popularly known as Araucaria, Brazilian pine, or Paraná pine, is native to Brazil and found in the mixed ombrophilous forest (Carvalho, 2003). The seed of A. angustifolia (araucaria nut) is a nutritious and energy-rich food that is rich in starch and proteins, presents a low glycaemic index (Cordenunsi et al, 2004; Franco, 2008) and is widely consumed by the Brazilian population (Zanette et al, 2011; Wendling, 2011). The unsustainable exploitation of this species, caused by the ever-increasing demand for araucaria nuts, seriously threatens the regeneration of Araucaria forests (Wendling, 2015). A. angustifolia is usually propagated by its seeds, which have low percentages of germination once they have been stored and are classified as recalcitrant. Faced with high demands for araucaria nuts, grafting techniques promote the propagation of successful genetic characteristics as well as early flowering and fruiting and the formation of seed production orchards (Hartmann, Kerster, Davies Jr, & Geneve, 2011)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
