Construction of chromosome segment substitution lines in peanut (Arachis hypogaea L.) using a wild synthetic and QTL mapping for plant morphology

Chromosome segment substitution lines (CSSLs) are powerful QTL mapping populations that have been used to elucidate the molecular basis of interesting traits of wild species. Cultivated peanut is an allotetraploid with limited genetic diversity. Capturing the genetic diversity from peanut wild relatives is an important objective in many peanut breeding programs. In this study, we used a marker-assisted backcrossing strategy to produce a population of 122 CSSLs from the cross between the wild synthetic allotetraploid (A. ipae¨nsis6A. duranensis)4x and the cultivated Fleur11 variety. The 122 CSSLs offered a broad coverage of the peanut genome, with target wild chromosome segments averaging 39.2 cM in length. As a demonstration of the utility of these lines, four traits were evaluated in a subset of 80 CSSLs. A total of 28 lines showed significant differences from Fleur11. The line6trait significant associations were assigned to 42 QTLs: 14 for plant growth habit, 15 for height of the main stem, 12 for plant spread and one for flower color. Among the 42 QTLs, 37 were assigned to genomic regions and three QTL positions were considered putative. One important finding arising from this QTL analysis is that peanut growth habit is a complex trait that is governed by several QTLs with different effects. The CSSL population developed in this study has proved efficient for deciphering the molecular basis of trait variations and will be useful to the peanut scientific community for future QTL mapping studies. (Résumé d'auteur

Chromosome number in Brazilian germplasm accessions of Paspalum hydrophilum, P. modestum and P. palustre (Gramineae; Paniceae)

This paper compiles results of chromosome counts of Paspalum hydrophilum, P. modestum and P. palustre. Four Brazilian accessions of P. modestum have shown 2n = 2x = 20 chromosomes, a number already found in one accession from Argentina and in two from Brazil. Three other Brazilian accessions showed tetraploid level (2n = 4x = 40), which was previously unknown in this species. In P. hydrophilum, only one of the accessions analyzed presented tetraploid level, initially established for the species from plants collected in Argentina. Five additional accessions from Brazil showed the diploid number, previously detected in a single Brazilian population. A tetraploid cytotype was found in P. palustre, previously known as a diploid species. In addition to confirming the occurrence of distinct ploidy levels for all three species, the results establish the predominance of the diploid level in P. hydrophilum and P. modestum accessions collected in Brazil

Taxonomy of Paspalum L., Linearia group (Gramineae - Paniceae) from Brazil

A systematic treatment of the Brazilian species of Paspalum tradicionally included in the informal group Linearia is provided, including the critical analysis of each species and of their synonymy, as well as considerations on the consistency of the group and its relationships with the adjacent Notata group. An analytical key is presented to diferentiate the taxa under treatment, including very similar species of the Notata group. Detailed morphological descriptions, illustrations, geographic and ecological data, and chromosome numbers are provided. Seven species are treated in detail: Paspalum approximatum, P. crispulum, P. dedeccae, P. ellipticum, P. filifolium, P. lineare and P. pallens. Paspalum ellipticum and P. pallens are not considered as very typical members of the Linearia alliance.Apresenta-se um tratamento sistemático das espécies brasileiras de Paspalum L., grupo Linearia e discute-se a naturalidade do mesmo. O tratamento engloba sete espécies, P. approximatum, P. crispulum, P. dedeccae, P. ellipticum, P. filifolium, P. lineare e P. pallens, incluindo chave analítica para os táxons do grupo e espécies afins, descrições detalhadas, sinonímia, ilustrações, dados sobre ecologia, números cromossômicos e distribuição geográfica, além de discussões sobre a delimitação do grupo. Paspalum ellipticum e P. pallens não são considerados como membros típicos do grupo Linearia.37138

Mode of reproduction of Brazilian species of Adesmia (Leguminosae)

Mode of reproduction was studied in 15 species of Adesmia DC. (Leguminosae). In six species, three treatments were used: mutual pollination, mechanical stimulation and control. Fifty-four plants of these six species were grown in a greenhouse, individually isolated in nylon screen boxes. Flowers were labelled and submitted to the different treatments. In addition, the frequency of spontaneous self-pollination in the absence of pollinators was studied in 200 plants of nine other species. These 200 plants were kept in a greenhouse, which avoided contact with any possible pollinator. Adesmia bicolor, A. muricata, A. punctata and A. riograndensis produced seed both by cross- and self-pollination. Adesmia punctata and A. riograndensis need mechanical stimulation for self-pollination. Adesmia incana reproduced by self-pollination; however, the possibility of cross-pollination cannot be totally ruled out. Adesmia tristis reproduced mainly by cross-pollination and a mechanism of self-incompatibility is suggested. Among the nine species that were not exposed to pollinators, A. securigerifolia produced a large amount of seed, indicating that it is a self-pollinating species. Adesmia arillata, A. araujoi, A. ciliata, A. psoraleoides, A. rocinhensis, A. reitziana, A. sulina and A. vallsii did not produce any seed under the experimental conditions, suggesting that they are cross-pollinated or that they need mechanical stimulation to reproduce.<br>Foram estudadas 15 espécies do gênero Adesmia DC. (Leguminosae), quanto ao modo de reprodução. Em seis espécies do gênero Adesmia, o modo de reprodução foi determinado através de três tratamentos: polinização mútua, estímulo mecânico e controle. As 54 plantas submetidas aos tratamentos foram cultivadas em casa de vegetação e mantidas isoladas individualmente, através de armações de tela de náilon. As flores foram marcadas e submetidas aos distintos tratamentos. Adicionalmente, foram observadas 200 plantas de outras 9 espécies do mesmo gênero quanto à ocorrência de autofecundação na ausência de polinizadores. As 200 plantas apenas isoladas e observadas foram cultivadas em vasos e mantidas em casa de vegetação telada, sem acesso de polinizadores. Os resultados mostraram que, das espécies investigadas pelos três tratamentos, A. bicolor, A. muricata, A. punctata e A. riograndensis são versáteis, pois permitiram a reprodução por fecundação cruzada e autofecundação. As duas últimas, para se autofecundarem, necessitaram de estímulo mecânico. Adesmia incana se reproduziu por autofecundação, mas não se descarta a possibilidade de ocorrer fecundação cruzada. Adesmia tristis se reproduziu quase que totalmente por fecundação cruzada e é possível a ocorrência de mecanismos de autoincompatibilidade. Das nove espécies apenas observadas, Adesmia securigerifolia se reproduziu por autofecundação, formando elevado número de sementes por planta. A. arillata, A. araujoi, A. ciliata, A. psoraleoides, A. rocinhensis, A. reitziana, A. sulina e A. vallsii não produziram sementes por autofecundação espontânea. Estas espécies são de fecundação cruzada ou necessitam do estímulo do polinizador

Brazilian Flora 2020: Leveraging the power of a collaborative scientific network

International audienceThe shortage of reliable primary taxonomic data limits the description of biological taxa and the understanding of biodiversity patterns and processes, complicating biogeographical, ecological, and evolutionary studies. This deficit creates a significant taxonomic impediment to biodiversity research and conservation planning. The taxonomic impediment and the biodiversity crisis are widely recognized, highlighting the urgent need for reliable taxonomic data. Over the past decade, numerous countries worldwide have devoted considerable effort to Target 1 of the Global Strategy for Plant Conservation (GSPC), which called for the preparation of a working list of all known plant species by 2010 and an online world Flora by 2020. Brazil is a megadiverse country, home to more of the world's known plant species than any other country. Despite that, Flora Brasiliensis, concluded in 1906, was the last comprehensive treatment of the Brazilian flora. The lack of accurate estimates of the number of species of algae, fungi, and plants occurring in Brazil contributes to the prevailing taxonomic impediment and delays progress towards the GSPC targets. Over the past 12 years, a legion of taxonomists motivated to meet Target 1 of the GSPC, worked together to gather and integrate knowledge on the algal, plant, and fungal diversity of Brazil. Overall, a team of about 980 taxonomists joined efforts in a highly collaborative project that used cybertaxonomy to prepare an updated Flora of Brazil, showing the power of scientific collaboration to reach ambitious goals. This paper presents an overview of the Brazilian Flora 2020 and provides taxonomic and spatial updates on the algae, fungi, and plants found in one of the world's most biodiverse countries. We further identify collection gaps and summarize future goals that extend beyond 2020. Our results show that Brazil is home to 46,975 native species of algae, fungi, and plants, of which 19,669 are endemic to the country. The data compiled to date suggests that the Atlantic Rainforest might be the most diverse Brazilian domain for all plant groups except gymnosperms, which are most diverse in the Amazon. However, scientific knowledge of Brazilian diversity is still unequally distributed, with the Atlantic Rainforest and the Cerrado being the most intensively sampled and studied biomes in the country. In times of “scientific reductionism”, with botanical and mycological sciences suffering pervasive depreciation in recent decades, the first online Flora of Brazil 2020 significantly enhanced the quality and quantity of taxonomic data available for algae, fungi, and plants from Brazil. This project also made all the information freely available online, providing a firm foundation for future research and for the management, conservation, and sustainable use of the Brazilian funga and flora

Growing knowledge: an overview of Seed Plant diversity in Brazil

Abstract An updated inventory of Brazilian seed plants is presented and offers important insights into the country's biodiversity. This work started in 2010, with the publication of the Plants and Fungi Catalogue, and has been updated since by more than 430 specialists working online. Brazil is home to 32,086 native Angiosperms and 23 native Gymnosperms, showing an increase of 3% in its species richness in relation to 2010. The Amazon Rainforest is the richest Brazilian biome for Gymnosperms, while the Atlantic Rainforest is the richest one for Angiosperms. There was a considerable increment in the number of species and endemism rates for biomes, except for the Amazon that showed a decrease of 2.5% of recorded endemics. However, well over half of Brazillian seed plant species (57.4%) is endemic to this territory. The proportion of life-forms varies among different biomes: trees are more expressive in the Amazon and Atlantic Rainforest biomes while herbs predominate in the Pampa, and lianas are more expressive in the Amazon, Atlantic Rainforest, and Pantanal. This compilation serves not only to quantify Brazilian biodiversity, but also to highlight areas where there information is lacking and to provide a framework for the challenge faced in conserving Brazil's unique and diverse flora