Diversidade genética, multiplicação e conservação in vitro de juazeiro (Zizyphus joazeiro Mart.) e amburana (Amburana cearensis [Allemão] A. C. Smith)

Abstract

Juazeiro and amburana are native species of the Caatinga and have multiple uses attributed to the food, medicinal, wood and environmental values that these plants have. However, their natural areas are under high anthropization process, which places these species in vulnerable conditions of extinction. The objective of this work was to carry out studies aiming to characterize the genetic divergence of native germplasms, as well as to establish a protocol of multiplication and conservation of the same. The works were conducted at Embrapa Semiarid, Petrolina- PE, and at the Federal Universities of Uberlândia and Lavras. In vitro multiplication of the juazeiro was used to induce explants (mini-cuttings) buds using doses of ANA (three doses) and BAP (five doses) - factorial 3 x 5 - and for the rooting two auxins were adopted, ANA and AIB, in four doses each factorial 2 x 4. In the in vitro conservation process the osmotic regulators, mannitol and sorbitol were tested, both in two doses, plus the control treatment, which constituted a 2 x 4 + 1 factorial. These seedlings were conserved for 240 days until growth resumption, which lasted 60 days. For the multiplication of the juazeiro the dose of 0,1 mg L-1 of ANA and 1,0 mg L-1 for induction of shoots is indicated, and as best inducer of rooting was obtained AIB. In the preservation process Sorbitol at 5 mg L-1 was more suitable for the in vitro conservation of Z. joazeiro. In the in vitro multiplication of amburana, four culture media - MS, MS/2, WPM and WPM/2 - four doses of BAP and two doses of sucrose were tested, which constituted a 4 x 4 x 2 factorial with six replicates and in DIC. In the second part, the effect of 0,05 and 0,1 mg L-1 doses of auxin AIA, ANA and AIB, plus the control, in a 3 x 2 + 1 factorial arrangement, with four replicates, were studied. The third phase, related to rooting, was the AIB in three doses (0,5, 1,0 and 2,0 mg L-1) and four residence times of the explants to the effect of this growth regulator, making a factorial 3 x 4 and four repetitions. In this paper it was concluded that MS medium with 30 g L-1 of sucrose and 0,6 mg L-1 of BAP promoted better responses to amburana multiplication and for induction of rooting it is recommended to use 2 mg L-1 of AIB. The genetic diversity experiment was based on the genetic patterns of 68 amburana accessions through cytometric analysis and ISSR molecular markers. Multivariate analyzes were applied using different clustering methods. The optimization method employed (Tocher) was consistent with all the hierarchical models used. The BB116 access was the one with the most divergent genetic pattern of the other genotypes and the Medium Binding method allowed the formation of more groups containing similar accessions.