Produção sexuada de progênies inermes de jurema branca (Piptadenia stipulacea (Benth.) Ducke).

Abstract

The Brazilian flora presents a great diversity of trees. This diversity is also observed in the Caatinga biome, which is unique to Brazil and occupies most of northeastern Brazil, a region characterized by the semi-aridity of its climate. Some trees have spines or thorns, which represent a defense against herbivores. This study had the objective to find jurema branca (Piptadenia stipulacea (Benth.) Ducke) trees capable to produce thornless progeny, estimate the percentage of seed germination, progenies ≥ 10 cm high and thornless progeny of each tree 125 days after sowing (DAS), compare the height and basal diameter of thornless and thorny progenies at 125, 190 and 311 DAS, and quantify the thorns of 125-DAS old progenies with height ≥ 10 cm. Treatments were allocated to the plots according to a completely random design with 2 x 15 factorial treatments [thorny and thornless progenies from 15 trees -10 thornless (Msem1 to Msem10) and five thorny (Mcom1 to Mcom5) trees]. The experiment was carried out during 311 days at the Forest Nursery facilities of the Academic Unit of Forestry/Center of Rural Health and Technology/Federal University of Campina Grande, in Patos-PB, Brazil (7 ° 03'33 "S and 37 ° 16'30 "W). On average, percentage of seed germination was approximately 50%, ranging from 10 to 82%, depending on the tree. The percentage of thornless progeny ranged from 8 to 63%, especially those from trees Msem5, Msem7 and Msem10, that represented 46, 40 and 63% of the seedlings ≥ 10 cm high at 125 DAS, respectively. Mean height and basal diameter of thornless seedlings tended to be lower than the values of the thorny progenies. However, the thornless seedlings from trees Msem5, Msem7 and Msem10 showed mean height and basal diameter surpassed only by five thorny progenies. The few thornless progenies of tree Mcom5 showed high mean height and basal diameter values. The Msem8 and Msem10’s progenies showed low quantity of thorns (10.2 and 10.3 thorns in the last 5 internodes, respectively), but the average thorn size was similar between progenies. Thus, five (Msem5, Msem7, Msem8, Msem10 e Mcom5) of the 15 considered trees should have their seeds collected and used to improve the production traits of jurema branca thornless progenies.