Abstract Peanut (Arachis hypogaea L.) is a tetraploid species with an A and B genome, while the majority of wild Arachis species are diploid with distinct genomes. In pre-breeding programs, one way to introgress interesting wild genes into peanut is by producing amphidiploids. This study aimed at the hybridization between distinct amphidiploids and their characterization, to combine high crossability with peanut, observed in some amphidiploids, with high pest and disease resistances observed in others. These new hybrids were called complex hybrids. Four amphidiploids previously obtained were crossed at four different combinations, and the derived complex hybrids were crossed with four peanut cultivars. Morphological, reproductive, chromosome complement, molecular markers for hybrid identification, phytopatological, and entomological characterizations were performed on the complex hybrids. All cross combinations resulted in complex hybrids. One complete complement of each diploid progenitor was confirmed in each hybrid. Plants of six distinct hybrid combinations were obtained between the complex hybrids and peanut. Based on morphological characterization, differences among progenies from distinct cross combinations were observed. Complex hybrids were considered more resistant to all diseases and pests than peanut cultivars. The simultaneous introgression of genes from four wild Arachis species into peanut was possible through the development of complex hybrids.

ABSTRACT In Brazil, the thrips (Enneothrips flavens Moulton) and rednecked peanutworm (Stegasta bosquella Chambers) are considered key pests for the peanut crop. Wild species show resistance to both of these pests, and can be used in breeding programs. The production of the sterile interspecific hybrids is necessary, which could be colchicine treated to get a synthetic amphidiploid with the same or similar genomic configuration of cultivated peanut. In this context, this study proposed the hybridization of wild pest-resistant species in 18 distinct combinations, obtaining the interspecific hybrids of Arachis and completing their characterization by (i) the reproductive characterization through pollen stainability with 2% acetocarmine (AC) solution with glycerin and 0.25% tetrazolium solution (TZ), (ii) the molecular certification of hybridization using microsatellite markers, and (iii) the morphological characterization using 61 morphological traits with Principal Component Analysis. Using reproductive, morphological and molecular characterizations, we identified six hybrid plants of the following crosses: three fromA. magna V 13751 × A. kuhlmannii V 9243, two from A. magna V 13751 × A. kempff-mercadoi V 13250, and one from A. magna K 30097 ×A. kuhlmannii V 7639. Amphidiploids can be reached based on these diploid plants and they can be used in breeding programs aiming pest resistance introgression.

ABSTRACT Peanut or groundnut (Arachis hypogaea L.) is a globally important oilseed crop, with important nutritional qualities, and a rich source of amino acids and protein. Another 80 species have been described in the genus Arachis, 64 of which are found in Brazil, and even though their morphology and agronomic traits remain largely unknown, they have been cultivated for forage and for landscaping and have great potential for breeding with cultivated peanut. Thus, the morphological characterization of wild Arachis species is essential for their conservation and use. In this study, we present a morphological and agronomic characterization of 29 diploid accessions of eleven wild Arachis species and one of the tetraploid A. monticola (section Arachis) with A and B genomes and determine their intra- and interspecific variability in greenhouse and field conditions. In total, 35 morphological descriptors were developed a priori from greenhouse accessions in the first crop year and used in field accessions in the second crop year. Significant differences in descriptors compiled in the greenhouse and the field support the use of different descriptors for different experimental conditions. PCA analysis showed that the distribution of accessions accorded with the taxonomy of species. The ten morphological descriptors that were important in differentiating section Arachis accessions were seed length, lateral branch length, right apical leaflet length, right apical leaflet width, height and diameter of main stem, branch color, standard petal base color, number of flowers, and presence of bristles on rachis.

RESUMO. O amendoim é uma cultura de grande importância para o agronegócio brasileiro. Um dos principais fatores que afetam sua produção é a incidência de pragas como o tripes-do-prateamento. O objetivo deste trabalho foi avaliar o potencial de resistência ao tripes, em genótipos derivados do cruzamento entre a cultivar IAC 503 e o anfidiploide (A. magna x A. cardenasii)4x, assim como estimar os parâmetros genéticos e fenotípicos em tais genótipos, como auxiliares no processo de seleção. Os experimentos foram conduzidos no esquema de blocos aumentados com testemunhas intercalares em duas gerações (F3 e F4). A resistência ao tripes foi avaliada pela sua infestação natural e pelos sintomas de injúrias causadas pelo inseto. Foram avaliados também, caracteres agronômicos como indicadores da proximidade dos genótipos segregantes ao cultivado. Com base nos resultados, observou-se que as progênies selecionadas apresentaram maior resistência ao tripes quando comparadas aos genótipos cultivados, tendo o anfidiploide como fonte de resistência ao inseto. Algumas progênies selecionadas como resistentes, também apresentaram bons componentes de produção, porém, com grau de adequação aos genótipos A. hypogaea L. ainda pequeno, o que sugere o uso de retrocruzamentos como alternativa na introgressão de genes de resistência e consequente recuperação dos genótipos adaptados dos genitores recorrentes.

ABSTRACT. Peanut is an oilseed crop of great importance for Brazilian agribusiness. A major factor affecting its production is pest incidence, mainly thrips. This study aimed to evaluate the potential for resistance to Enneothrips flavens in genotypes derived from the cross between IAC 503 and the amphidiploid (A. magna x A. cardenasii)4x and to estimate the genetic and phenotype parameters in these genotypes, allowing for better targeting in the selection. The experiments were conducted in a Federer augmented block design with additional checks in two generations (F3 and F4). Resistance to thrips was evaluated by its natural infestation and the symptoms of attacks by the insect. They were also evaluated using agronomic trait indicators of interspecific segregating with cultivated species. The results indicated that the selected progeny exhibited high resistance to thrips compared to commercial genotypes, and they had the amphidiploid as the insect resistance source. Some progenies selected as resistant also had good production traits, but with the degree of suitability to the A. hypogaea L. genotypes still low, the use of a backcross as an alternative for the introgression of resistance genes and the consequent recovery of adapted genotypes of superior recurring parents is suggested.

Peanut (Arachis hypogaea) is the fifth most produced oil crop worldwide. Besides lack of water, fungal diseases are the most limiting factors for the crop. Several species of Arachis are resistant to certain pests and diseases. This study aimed to successfully cross the A-genome with B-K-A genome wild species previously selected for fungal disease resistance, but that are still untested. We also aimed to polyplodize the amphihaploid chromosomes; cross the synthetic amphidiploids and A. hypogaea to introgress disease resistance genes into the cultivated peanut; and analyze pollen viability and morphological descriptors for all progenies and their parents. We selected 12 A-genome accessions as male parents and three B-genome species, one K-genome species, and one A-genome species as female parents. Of the 26 distinct cross combinations, 13 different interspecific AB-genome and three AA-genome hybrids were obtained. These sterile hybrids were polyploidized and five combinations produced tetraploid flowers. Next, 16 combinations were crossed between A. hypogaea and the synthetic amphidiploids, resulting in 11 different hybrid combinations. Our results confirm that it is possible to introgress resistance genes from wild species into the peanut using artificial hybridization, and that more species than previously reported can be used, thus enhancing the genetic variability in peanut genetic improvement programs.

Neste trabalho avaliou-se, em condições de campo, o potencial de resistência à mancha preta (Cercosporidium personatum) em plantas F4, selecionadas de cruzamentos entre genótipos de Arachis hypogaea (acessos VGaRoSv 12549 e VGaRoSv 12548 e a cultivar IAC Caiapó) e um anfidiplóide sintético (Arachis ipäensis x Arachis duranensis)4x. O experimento foi desenvolvido no ano agrícola de 2007/2008, em Pindorama (SP). Avaliaram-se noventa e três famílias de plantas em F4, em parcelas com dez plantas distribuídas em linhas de três metros de comprimento, espaçadas de dois metros, bem como os controles, as cultivares IAC Caiapó e Runner IAC 886, a espécie A. ipäensis e o anfidiplóide. Foram realizadas três avaliações da doença durante o ciclo, utilizando uma escala diagramática de notas visuais de sintomas de lesões e desfolha. Avaliaram-se também alguns caracteres morfoagronômicos, como indicativos da proximidade do material silvestre com o cultivado. A variabilidade da resistência à doença foi estudada através das médias de ASCPD (Área sob a Curva de Progresso da Doença). Pelos resultados constata-se que o anfidiplóide utilizado é interessante fonte de resistência. A seleção pelo método genealógico propiciou obter indivíduos com resistência ao nível do parental silvestre, mas as chances de se obter indivíduos resistentes e com caracteres agronômicos desejáveis é pequena, sugerindo a necessidade de retrocruzamentos.

Resistance to late leafspot (Cercosporidium personatum) was evaluated under field conditions in F4 plant populations selected from crosses between Arachis hypogaea genotypes (accessions VGaRoSv 12549 and VGaRoSv V12548 and the cultivar IAC Caiapó) and a synthetic amphydiploid (Arachis ipäensis x Arachis duranensis)4x. The experiment was carried out during 2007/2008 in Pindorama, State of São Paulo. Ninety and three F4 families were evaluated in plots of ten plants distributed along three-meter rows, with two meters spacing between rows. Cultivars IAC Caiapó and Runner IAC 886, as well as the wild species A. ipäensis and the amphydiploid were used as references (control). Some morphological and agronomic attributes were also evaluated as indicators of proximity between the wild parent and the cultivated peanut. Disease resistance variability was studied through estimates of AUCDP (Area Under the Curve of Disease Progress). The results showed that the amphydiploid used in these crosses is an interesting source of resistance. Selection by the pedigree method yielded F4 resistant individuals at the level of the wild resistant parent, but the chances of obtaining resistant plants with agronomic desirable traits is small, indicating the need for backcrossings.

No Brasil, diversas pragas podem atacar o amendoinzeiro, sendo o tripes-do-prateamento, Enneothrips flavens Moulton (Thysanoptera: Thripidae), a principal delas. Com o objetivo de avaliar a infestação e os sintomas dessa praga em diferentes acessos de espécies silvestres, anfidiplóides e cultivares de amendoinzeiro, foi instalado um experimento em campo, no município de Pindorama (SP ), no ano agrícola de 2007/2008. O delineamento estatístico adotado foi o de blocos ao acaso, com 48 tratamentos e cinco repetições. A formação das mudas foi feita em copos com substrato em casa de vegetação, sendo o plantio realizado em outubro/novembro de 2007. Foram realizadas amostragens a partir dos 30 dias após o plantio das mudas no campo, repetidas a cada 15 dias, num total de cinco avaliações, em cinco folíolos fechados por planta. Foram anotadas a presença e ausência de tripes em folíolos ainda fechados e atribuídas notas dos sintomas de dano aos folíolos recém-abertos, baseando-se em uma escala de notas variando de 1 a 5, sendo nota 1 sem dano de ataque; nota 2 limbo foliar com 1% a 25% da superfície com estrias e deformações; nota 3, 26 a 50%; nota 4, 51 a 75%; e, nota 5, 76% a 100%. Os acessos com menor porcentagem de presença de tripes e notas de sintomas foram VS 14957 (A. gregoryi), V13832 (A. stenosperma), V8979 (A. kuhlmannii), V9912 (A. kuhlmannii), V7639 (A. kuhlmannii) e VMiIrLbGv14309 (A. villosa). Dentre os acessos mais sensíveis ao tripes situaram-se V12549 (Arachis hypogaea),Ac2562 (A. hypogaea) e as cultivares IAC Caiapó (A. hypogaea) e IA C Runner 886 (A. hypogaea).

In Brazil, various pests are reported to infest peanut crop, being the thrips Enneothrips flavens the most important. Accesses of wild peanut species, anfidiploide and peanut cultivars were evaluated in field conditions at Pindorama, São Paulo State, at the agricultural year of 2007/2008. The experiment consisted of a complete ramdomized block design with 48 treatments and five replications. The material was sown in small bags under greenhouse conditions. Plantings were carried out in October/November 2007. Starting at 30 days after planting in the field, evaluations were done at 15-day intervals, in five closed leaves of each plant. The following data were obtained: presence or absence of thrips in each leaf; symptoms of thrips damage in recently opened leaves, based on a 1-5 scale where 1 = without damage, 2 = 1 to 25% of the leaf surface with damage (grooves and deformations), 3 = 26 to 50%, 4 = 51 to 75% and 5 = 76 to 100% of damage symptoms. The accesses with the least damages and insect presence were: VS 14957 (A. gregoryi), V13832 (A. stenosperma), V8979 (A. kuhlmannii), V9912 (A. kuhlmannii), V7639 (A. kuhlmannii) e VMiIrLbGv14309 (A. villosa). The most sensitive accesses were V12549 (A. hypogaea), Ac2562 (A. hypogaea) and the commercial A. hypogaea genotypes IAC Caiapó and IAC Runner 886.

O amendoim (Arachis hypogaea) possui genoma AB e é uma das mais importantes culturas oleaginosas em todo o mundo. Os principais problemas da cultura no Brasil são as doenças fúngicas. Várias espécies do gênero Arachis são resistentes a pragas e doenças. Este trabalho visou a identificar espécies silvestres pertencentes à seção Arachis associadas aos genomas A ou B (ou " não-A" ) do amendoim que são resistentes à mancha castanha (Cercospora arachidicola), mancha preta (Cercosporidium personatum) e ferrugem (Puccinia arachidis). Para a identificação de genótipos resistentes a doenças fúngicas, bioensaios utilizando folhas destacadas foram realizados em condições de laboratório, com inoculação artificial, temperatura controlada de 25ºC e fotoperíodo de 10h luz/14h escuro, por 20-42 dias, de acordo com a espécie fúngica. A maioria dos acessos das espécies silvestres foram mais resistentes que os acessos de A. hypogaea para uma, duas ou todas as espécies fúngicas estudadas. Arachis monticola, considerada como o possível ancestral tetraplóide ou como um derivativo de A. hypogaea, também mostrou-se mais suscetível a Cercosporidium personatum e Puccinia arachidis, quando comparado à maioria das espécies silvestres. Portanto, acessos de germoplasma silvestre com genoma A ou B estão disponíveis para serem utilizados na introgressão de genes de resistência a doenças fúngicas no amendoim.

Groundnut (Arachis hypogaea) has an AB genome and is one of the most important oil crops in the world. The main constraints of crop management in Brazil are fungal diseases. Several species of the genus Arachis are resistant to pests and diseases. The objective of our experiments was to identify wild species belonging to the taxonomic section Arachis with either A or B (or " non-A" ) genomes that are resistant to early leaf spot (Cercospora arachidicola), late leaf spot (Cercosporidium personatum) and rust (Puccinia arachidis). For the identification of genotypes resistant to fungal diseases, bioassays with detached leaves were done in laboratory conditions, with artificial inoculation, a controlled temperature of 25ºC and a photoperiod of 10 h light/14 h dark, for 20-42 days, depending on the fungi species. Most of the accessions of wild species were more resistant than accessions of A. hypogaea for one, two or all three fungi species studied. Arachis monticola, considered to be a possible tetraploid ancestor or a derivative of A. hypogaea, was also more susceptible to Cercosporidium personatum and Puccinia arachidis, as compared to most of the wild species. Therefore, wild germplasm accessions of both genome types are available to be used for the introgression of resistance genes against three fungal diseases of peanut.

O gênero Arachis possui 69 espécies, sendo a maioria nativa do Brasil. Ápices radiculares de plântulas têm sido usados para a obtenção de células em divisão. Diversas espécies silvestres produzem pouca quantidade de sementes, o que dificulta a obtenção de meristemas para preparações citológicas. O objetivo deste trabalho foi avaliar a capacidade de enraizamento de diversas espécies silvestres de Arachis, usando a técnica de folhas destacadas para a obtenção de raízes a partir de pecíolos. Foram avaliados 130 acessos e 27 híbridos interespecíficos aos 15, 31 e 49 dias após o plantio. A formação de raízes a partir de folhas observada em espécies silvestres confirmou a ampla variabilidade genética típica do gênero Arachis, indicando que o número de dias também interfere na porcentagem de enraizamento. A Secção Arachis apresentou a maior taxa de enraizamento de folhas e a Secção Caulorrhizae apresentou o mesmo padrão da Secção Erectoides. Acessos pertencentes às Secções Heteranthae, Trierectoides, Extranervosae e Rhizomatosae não diferiram com relação à porcentagem de enraizamento. A Secção Erectoides apresentou comportamento similar ao das Secções Rhizomatosae e Extranervosae. A quantidade e morfologia de raízes obtidas por meio dessa técnica mostraram-se promissoras para uso em preparações citológicas.

The genus Arachis has 69 species, the majority native to Brazil. Arachis spp. seedling root tips have been used to obtain dividing cells for cytological preparations. Several wild species produce small amounts of seeds and consequently few root meristems, making the cytogenetic characterization very difficult. The purpose of this study was to evaluate the rooting capacity of several wild species of Arachis using the detached leaves technique for obtaining roots from petioles. One hundred and thirty accessions and 27 interspecific hybrids were studied. Three evaluations were performed at 15, 31, and 49 days after planting. Leaf rooting observed in the wild species confirmed the great genetic variability typical of the Arachis genus, indicating that the number of days interferes with the rooting percentage. The Arachis Section presented the highest rate of rooting leaves. The Caulorrhizae Section showed the same pattern observed in the Erectoides Section. Accessions from Heteranthae, Trierectoides, Extranervosae, and Rhizomatosae Sections did not differ among each other. Differences were not observed in Erectoides Section when compared to Rhizomatosae and Extranervosae Sections. The number and morphology of roots obtained through this technique were promising to be used on cytological preparations.

Caracterizaram-se morfologicamente os acessos de germoplasma de espécies silvestres brasileiras de amendoim do gênero Arachis L., Sect. Arachis e analisaram-se a similaridade genética entre acessos da mesma espécie e entre as espécies. Realizou-se o experimento nos anos agrícolas de 1993 a 1996, no Núcleo Experimental de Campinas, do Instituto Agronômico (IAC). Avaliaram-se os acessos disponíveis no Banco Ativo de Germoplasma de Espécies Silvestres de Arachis, da Embrapa Recursos Genéticos e Biotecnologia (CENARGEN - Brasília, DF), das espécies A. palustris Krapov., W.C. Gregory & Valls, A. decora Krapov., W.C. Gregory & Valls, A. praecox Krapov., W.C. Gregory & Valls e A. stenosperma Krapov. & W.C. Gregory, efetuando-se anotações fenotípicas quantitativas e qualitativas, conforme lista de descritores morfológicos. Observou-se que os acessos de A. stenosperma são semelhantes, apesar da sua grande distância geográfica, e diferem das demais espécies, formando um grupo mais coeso. Caracteres como o diâmetro do eixo central e o comprimento dos frutos e das sementes serviram para distingui-la das demais espécies. Arachis decora apresentou alta variação entre acessos nos vários caracteres morfológicos estudados. A. palustris apresentou alta variação morfológica entre acessos, ainda que tenham sido analisados apenas dois, para altura da planta, largura da semente, dimensões do esporão, istmo, folíolo, raque e eixo central e quanto à presença e ausência de tricomas no folíolo. Arachis praecox, representada por um único acesso, aproximou-se mais de A. decora que das demais espécies.

In this work, a morphological characterization of germplasm accessions of wild Brazilian species of peanut, section Arachis was accomplished. Also, an analysis of the genetic similarity among accessions and between species was evaluated. The experiment was undertaken from 1993 to 1996, at the Campinas Experimental Station of the Instituto Agronômico (IAC). Accessions evaluated were made available by the Wild Arachis Genebank of Embrapa Recursos Genéticos e Biotecnologia (CENARGEN - Brasília, DF) and include A. palustris Krapov., W.C. Gregory & Valls, A. decora Krapov., W.C. Gregory & Valls, A. praecox Krapov., W.C. Gregory & Valls and A. stenosperma Krapov. & W.C. Gregory. Quantitative and qualitative phenotypic data were collected according a list of morphological descriptors. Results showed that accessions of A. stenosperma are very similar, despite the large geographical distance between them. Also, this species forms an isolated group, distant from the other species. Characters such as main stem diameter, fruit and seeds length were useful to separate A. stenosperma from the other species. Arachis decora has a high variation between accessions for many characters used. Arachis palustris shows high morphological variation between accessions, although only two accessions were studied, concerning plant height, seed width, peg, isthmus, leaflet, rachis, and main stem dimensions, presence or absence of hairs on the leaflet. Arachis praecox, represented in this work by a single accession, is more similar to A. decora than to other species.

Avaliaram-se características de sementes de 22 espécies de gramíneas nativas do cerrado, como: ocorrência de esterilidade, massa de sementes cheias e vazias, possibilidade de ventilação e quantidade de sementes por peso. As espécies dos gêneros Aristida, Ctenium, Diectiomis e Schizachyrium apresentaram os maiores índices de espiguetas férteis (superior a 50%), enquanto as dos gêneros Andropogon e Hypogynium apresentaram valores intermediários (25-49%); em Paspalum, Setaria e Thrazya, a ocorrência de espiguetas férteis foi baixa (5-24%), e em Axonopus, muito baixa (inferior a 5%). O número médio de sementes cheias por grama variou de 20 em Paspalum reduncum a quase 3.000 em Aristida gibbosa; esta informação é importante na determinação da taxa de semeadura. As espécies consideradas palhentas, a respeito das quais recomenda-se o uso de desaristadores no beneficiamento, são as seguintes: Andropogon bicornis, Andropogon selloanus, Aristida gibbosa, Aristida recurvata, Aristida setifolia, Aristida torta, Ctenium cirrhosum, Diectiomis fastigiata, Hypogynium virgatum, Paspalum pectinatum, Paspalum polyphilum, Paspalum splendens, Paspalum stellatum e Schizachyrium microstachyum. As espécies classificadas como não palhentas, para as quais pode-se recomendar a ventilação, são: Axonopus barbigerus, Axonopus canescens, Paspalum gardnerianum, Paspalum pilosum, Paspalum reduncum, Paspalum trichostomum, Setaria geniculata e Thrasya glaziovii.

Some characteristics of seeds of 22 native grass species from cerrado region in Brazil, such as sterility, weight of full and empty seeds, possibility of ventilation and number of seeds per weight were evaluated. Species of the genus Aristida, Ctenium, Diectiomis and Schizachyrium showed the highest levels of fertile spikelets (higher than 50%); Andropogon and Hypogynium showed levels of fertile spikelets between 25-49%; whereas in Paspalum, Setaria and Thrazya the occurrence of fertile spikelets varied from 5 to 24% and in Axonopus it was lower than 5%. The average number of full seeds per gram varied from 20 in Paspalum reduncum to almost 3,000 in Aristida gibbosa, which affects the rate of sowing. The seeds classified as "hairy", with which the use of "de-awners" during processing is recommended, belonged to the species: Andropogon bicornis, Andropogon selloanus, Aristida gibbosa, Aristida recurvata, Aristida setifolia, Aristida torta, Ctenium cirrhosum, Diectiomis fastigiata, Hypogynium virgatum, Paspalum pectinatum, Paspalum polyphilum, Paspalum splendens, Paspalum stellatum and Schizachyrium microstachyum. The species classified as non "hairy", with which ventilation can be recommended, were: Axonopus barbigerus, Axonopus canescens, Paspalum gardnerianum, Paspalum pilosum, Paspalum reduncum, Paspalum trichostomum, Setaria geniculata and Thrasya glaziovii.