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The genus Cedrela comprises endangered and highly valuable species in the forestry sector. Based on molecular genetics, we describe the natural distribution areas, ecological niches, and current state of four Cedrela species distributed in Argentina, in order to apply proper conservation strategies, guide germplasm collection, and design suitable seed orchards. Genetic variability patterns of C. angustifolia populations are associated with the latitudinal and altitudinal gradients of distribution, as well as with its selective logging history in the Yungas Rainforest; instead, genetic patterns of C. balansae were related to the short geographic distance among their populations and the high levels of historical gene flow between them. Molecular evidence of hybrid zones between C. balansae and C. saltensis in the Yungas Rainforest is presented together with their genetic patterns of variation and geographical delimitation of their altitudinal ranges. In addition, the molecular identification was used for the specific purification of clonal seed orchards of C. balansae. In the Alto Parana Rainforest, genetic variability of C. fissilis populations was evaluated. Strategies for use and conservation of Cedrela genetic resources are discussed.

This chapter gathers three species locally known for their multipurpose use whose natural forests were overexploited and intensively logged, both for the use of the wood and due to the advance of the agricultural frontier. Their natural ranges and disjunct distribution areas are described, as well as their economic relevance. The adjustment of molecular protocols for these non-model species is not trivial, and results are presented together with the initial studies for the genetic characterization of their natural populations through molecular markers. Domestication experiences including seed physiology, nursery, silviculture, breeding, and propagation techniques showed different advances in each species. Incipient breeding strategies for Cordia trichotoma and Handroanthus impetiginosus developed particular sampling procedures and massal selection in the natural stands. Vegetative propagation of the selected individuals is being performed for the establishment of clonal seed orchards. The potential of Anadenanthera colubrina var. cebil to be included in domestication programs in Argentina is discussed. Finally, the future steps in breeding and conservation programs are delineated.

Argentina has two disjunct rainforests, with similarities and differences, which share genera and species. The exploitation of their forest resources accompanied the historical development of the regions related. The Yungas has functioned as a provider of hardwood for the domestic market, even representing the illegal logging a great portion of the business, with severe environmental impacts. The overexploitation of the species of most valuable wood in the past has led to their present scarcity and a current trend to exploit those that are more abundant but of lower quality. The replacement of natural forests by industrial plantations of fast-growing exotic species has become a particular threat in the Alto Parana Rainforest. Natural protected areas of both rainforests are presented. The main forest tree species with breeding potential are described. Some general considerations for a sustainable management of the Argentinean rainforests from a breeding point of view are discussed, including interspecific hybridization.

Cedrela lilloi C. DC. (cedro coya, Meliaceae), an important south American timber species, has been historically overexploited through selective logging in Argentine Yungas Rainforest. Management and conservation programs of the species require knowledge of its genetic variation patterns; however, no information is available. Molecular genetic variability of the species was characterized to identify high-priority populations for conservation and domestication purposes. Fourteen native populations (160 individuals) along a latitudinal gradient and with different logging's intensities were assessed by 293 polymorphic AFLP (amplified fragment length polymorphism) markers. Genetic diversity was low (Ht = 0.135), according to marginal location of the species in Argentina. Most of the diversity was distributed within populations (87%). Northern populations showed significant higher genetic diversity (R(2)= 0.69) that agreed with latitudinal pattern of distribution of taxonomic diversity in the Yungas. Three clusters were identified by Bayesian analysis in correspondence with northern, central, and southern Yungas. An analysis of molecular variance (AMOVA) revealed significant genetic differences among latitudinal clusters even when logging (Φ(RT) = 0.07) and unlogging populations (Φ(PT) = 0.10) were separately analyzed. Loss of genetic diversity with increasing logging intensity was observed between neighboring populations with different disturbance (Φ(PT) = 0.03-0.10). Bottlenecks in disturbed populations are suggested as the main cause. Our results emphasize both: the necessity of maintaining the genetic diversity in protected areas that appear as possible long-term refuges of the species; and to rescue for the national system of protected areas some high genetic diversity populations that are on private fields.