Floral biology of cacauhy (Theobroma speciosum - Malvaceae)

Silva

Arenas-de-Souza

et al. 2017

Nativa

Recebido em março/2017; Aceito em agosto/2017. RESUMO:O estudo objetivou analisar a diversidade genética de Theobroma speciosum e Theobroma subincanum em um fragmento florestal no município de Alta Floresta, Mato Grosso, Brasil. Foram amostrados aleatoriamente 21 indivíduos T. speciosum e 20 de T. subincanum. Sete primers ISSR foram utilizados e produziram 35 fragmentos dos quais 42,8% apresentaram polimorfismo para T. speciosum e 57,1% para T. subincanum. A diversidade genética de Nei e o Índice de Shannon foram de 0,133 e 0,201 para T. speciosum e 0,244 e 0,351 para T. subincanum respectivamente. O dendrograma UPGMA apresentou quatro grupos para T. speciosum e três grupos para T. subincanum. Os marcadores ISSR foram capazes de acessar a diversidade das duas espécies em estudo gerando informações para programas de conservação e melhoramento genético e demonstraram que a fragmentação vegetal ocasionou um efeito maior sobre a diversidade genética da espécie T. speciosum nas populações estudadas. Os níveis de diversidade encontrados no estudo indicam existência de variabilidade genética e alertam para a importância da conservação in situ destas populações como fonte de genes para o melhoramento genético do gênero Theobroma. Palavras-chave: Cacauí. Cupuí, fragmentação florestal, ISSR.Genetic diversity of two species of Theobroma L. in a forest fragment in Amazon Portal, MT, Brazil ABSTRACT:This study aimed to analyze the genetic diversity of Theobroma speciosum and Theobroma subincanum in forest fragment in the municipality of Alta Floresta, Mato Grosso, Brazil. We randomly sampled twenty-one T. speciosum individuals and twenty T. subincanum individuals. The seven ISSR primers used produced 35 fragments, from which 42,8% were polymorphic for T. speciosum and 57,1 % were polymorphic for T. subincanum. The Nei's genetic diversity and Shannon index respectively were 0,133 and 0,201 for T. speciosum and 0,244 and 0,351 for T. subincanum. The UPGMA dendrogram showed four clusters for T. speciosum and three clusters for T. subincanum. The ISSR markers were able to access the genetic diversity of the two species studied, thus they provided information for conservation and breeding programs, also demonstrated that forest fragmentation caused a greater effect on genetic diversity of the T. speciosum species in the populations studied. The levels of diversity found in the study indicate that there is genetic variability and alert to the importance of in situ conservation of these populations as a source of genes for the genetic improvement of the genus Theobroma.

Section: Discussionunclassified

“…e o cupuí (Theobroma subincanum Mart.) são importantes por representarem um banco de genes a serem utilizados no melhoramento genético das espécies cultivadas comercialmente VENTURIERI, 2010).…”

Section: Introductionunclassified

Diversidade genética de duas espécies de Theobroma L. em um fragmento florestal no Portal da Amazônia, MT, Brasil

Silva

Arenas-de-Souza

et al. 2017

Nativa

“…Similarly, in studies of T. cacao, Motamayor et al (2002) and Sereno et al (2006) found H e (0.540 and 0.566, Both adults and subadults showed evidence of inbreeding. T. speciosum is considered a self-incompatible species (Souza & Venturieri, 2010); therefore, inbreeding is likely the result of mating among relatives. This can be explained by the pollen dispersal distances found for Theobroma species, and particularly T. speciosum, which is mainly pollinated by Phoridae (Silva & Martins, 2004) and associated with the presence of SGS.…”

mentioning

confidence: 99%

Diversity and spatial genetic structure of a natural population of Theobroma speciosum (Malvaceae) in the Brazilian Amazon

Dardengo

Silva

et al. 2016

RBT

Abstract:The quantification of genetic diversity and intrapopulation spatial genetic structure (SGS) of tree species are important aspects for in and ex situ conservation practices. In this study we seek to understand the importance of conservation areas by quantifying the genetic diversity and the spatial genetic structure of a natural population of Theobroma speciosum. Within this population, 49 adults and 51 subadults were genotyped for five microsatellite loci. The results showed that adults and subadults have similar levels of genetic diversity and inbreeding (adults: A= 10.4, A e = 10.3, F= 0.68, subadults: A= 10.6, A e = 10.6, F= 0.57). Genetic diversity was spatially structured within the population, and the results suggest that near-neighbor trees up to a distance of 70 m are likely related. SGS is likely the result of short-distance seed dispersal, the short-distance range of pollinators, and infrequent breaches of the self-incompatible mating system. Considering the high demographic density of the species and size of the study area, as well as the high average number of alleles per locus and the presence of rare alleles, we believe that the study population is an excellent resource for in situ genetic conservation of T. speciosum. The study area is also a useful resource for collecting germplasm for ex situ conservation and seed collection, either for breeding programs used in the restoration of degraded areas or forest improvement. Rev. Biol. Trop. 64 (3): 1091-1099. Epub 2016 September 01.Key words: Amazonia, genetic variability, microsatellite markers, cacauhy.The national program of biological diversity, that evaluated and identified priority areas for conservation, sustainable use, and benefitsharing of biodiversity of the Brazilian Amazon, established 27 ecoregions of the Brazilian Legal Amazon (PNJU, 2013). One ecoregion is the Mato Grosso dry forests located in the Northern part of Mato Grosso State. In this area, the Juruena National Park (Parque Nacional do Juruena) was established in 2006 with the aim of protecting endemic Amazonian species. The Conservation Unit (CU) includes headwaters and stretches of important Amazonian rivers, such as Aripuanã, a tributary of the Madeira, Juruena, and Teles Pires Rivers, and tributaries of the Tapajós, and it encompasses an area of significant biogeographical interest. The genus Theobroma occurs naturally in the area.Several species within the Theobroma genus have conventional or potential uses, including Theobroma speciosum Willd. ex Spreng, commonly known as cacauhy. This species is important because it represents a possible source of genetic resistance for other, more economically important species, such as Theobroma cacao (Silva et al., 2011). The fruit rind of T. speciosum is mixed with wood ash to produce a handmade soap that is used in the Amazon and it is an excellent deodorant (Di Stasi & Hiruma-Lima, 2002). In relation to its fatty acids, Gilabert-Escrivá et al. (2002) noted that the composition is very similar to that found in cocoa butter. ...

“…In a similar study comparing natural and exploited Shorea megistophylla populations, Murawskiet, Dayanandan & Bawa (1994) have found differences in the inbreeding levels of different populations, as well as changes such as increased selfing in the reproductive behavior of exploited populations. However, Theobroma speciosum is a self-incompatible species (Souza & Venturieri, 2010) that, according to Silva and Martins (2004), presented adequate pollination syndrome by Diptera saprophages. Drosophila sp.…”

Section: Discussionmentioning

confidence: 99%

The effects of fragmentation on the genetic structure of Theobroma speciosum (Malvaceae) populations

Dardengo

Varella

2017

RBT

Native Theobroma species, such as cacauhy, are losing their habitat due to the intense forest fragmentation in the Amazon region, and preserving their genetic diversity has been the focus of many conservation programs. The aim of the present study is to assess whether fragmentation and habitat reduction affect its genetic structure and lead to genetic diversity losses in natural Theobroma speciosum populations. The study was conducted in two Mato Grosso State (Brazil) locations: Apiacás and Alta Floresta counties. Juruena National Park (JNP) in Apiacás County holds a natural T. speciosum population that has not suffered anthropic influences. A population composed of individuals from three anthropized urban forest parks (UF) in Alta Floresta County was analyzed for comparison. The leaves of 75 T. speciosum individuals distributed in the urban forest fragments and of 100 individuals found in the Juruena National Park were sampled. All nine microsatellite loci showed high polymorphism levels between categories (adults and sub-adults), in both populations. The sub-adult individuals of the fragmented area had a higher value (0.71), and the preserved population, the same value (0.69). The analysis of molecular variance showed 83 % genetic diversity within categories; 16 %, between populations; and only 1 %, between categories. Although the effects were small, a persistent fragmentation process can increase inbreeding and facilitate genetic drift, leading T. speciosum populations to inbreeding depression and loss of diversity. Rev. Biol. Trop. 66(1): 218-226. Epub 2018 March 01.Key words: genetic variability, cacauhy, inbreeding, Amazon, anthropic influence, microsatellite.The Amazon is an extraordinary supplier of natural resources to the Brazilian and world populations. The sustainable use of these resources and the lack of biological knowledge about most of the Amazonian flora species are challenges for future generations (Silva et al., 2015).Theobroma speciosum Willd. ex Spreng. (cacauhy) is native to the Amazonian region and it is distributed in primary forests of unflooded lands. This species, although little known, is important because it represents a possible source of resistance among most of the economically relevant species belonging to genus Theobroma (Silva et al., 2015).Native Theobroma species, such as cacauhy, are losing their habitat due to the intense forest fragmentation in the Amazon, and thus preserving the genetic diversity has been the main goal of most conservation programs focused on preserving the gene of interest and on allowing species variability maintenance at genetic level (Bekessy et al., 2002).Forest fragmentation decreases the number of individuals in a given population and, consequently, favors genetic variation losses. Genetic drift is the measured gene frequency of these individuals. In the short term, apart from the gene frequency of the original population, including the allele losses, genetic drift may occur in this small population. It is likely to have increased inbre...