Genetic divergence in Agave accessions through ISSR markers and phenotypic traits

Abstract

The Agave genus is composed of about 200 species, but the cultivation of sisal for fiber production in Brazil is restricted to two species: Agave sisalana and Agave fourcroydes, both have several accessions with wide variability. The collection of Agave of Embrapa has 37 accessions maintained in situ and periodically evaluated agronomical traits. Most of these accessions have phenotypic similarities, although they differ in fiber quality, which are widely used for commercial purposes. The identification of promising accesses contributes to the advance in improvement works, focusing on commercial indication. In order to estimate the genetic divergence of this collection, a cluster analyses was performed based on Inter-Simple Sequence Repeat (ISSR) markers and phenotypic traits. Genomic DNA from these accessions were used in polymerase chain reaction (PCR) with thirty ISSR oligonucleotides. For phenotypic characterization, twelve descriptors were adopted based on morphological and agronomic data. The Unweighted Pair Group Method with Arithmetic Mean (UPGMA) and Tocher multivariate methods were adopted. Thirteen groups were formed by the Tocher Method and six by UPGMA; however UPGMA method was more representative in the group formation. The comparison of the band patterns among accessions derived from the shoots showed that genetic variability is generated during asexual reproduction in these plants. The four lines generated from Tatui were the most divergent accessions. These plants are tallest, with higher mass values of fresh and dry mucilage, fresh and dry fiber mass, fiber length and presence of spines at the edges. The accessions from Instituto Agronômico de Campinas (IAC) showed the lowest genetic distances, indicating a possible narrow genetic base and high kinship degree. The crossings between H-RN, H-Kenya, H-400 fls, and H-11648 with Tatuí 1, 2, 3, and 4 can be a valorous strategy to broadening genetic diversity among commercial and native sisal germplasm.

Rescuing the Brazilian Agave breeding program: morphophysiological and molecular characterization of a new germplasm

“…In Mexico, A. fourcroydes has been reported to have at least five traditional cultivars (Colunga-García Marín et al, 1999) and variable ploidy (Robert et al, 2008). Nevertheless, in Brazil, only two closely related accessions, "Remigio" and "Cabinho", have been classified (Souza et al, 2018), although it is not clear how they relate to the Mexican cultivars. In our phylogenetic inference, the A. fourcroydes sample was grouped with A. angustifolia, a species, that is, supposed to be its wild ancestor (Colunga-García Marín et al, 1999), but was closer to A. rhodachanta samples, highlighting the intertwined nature of the A. angustifolia complex (Rivera-Lugo et al, 2018;Lledías et al, 2020).…”

“…Consequently, national investment in Agave research decreased dramatically, leading to the end of the country's only breeding program. A few of the materials developed by IAC were transferred to the germplasm bank of the Brazilian Agricultural Research Corporation-Embrapa, in Monteiro PB, Brazil (Suinaga et al, 2007;Souza et al, 2018;Monja-Mio et al, 2019;Raya et al, 2021), while some remained at IAC in Campinas.…”

Molecular epidemiology of sisal bole rot disease suggests a potential phytosanitary crisis in Brazilian production areas

“…Nevertheless, some more productive Agave cultivars like H11648 or H400 leaves ("híbrido 400 folhas" in Portuguese, named simply H400 from this point forward) can eventually be found in sisal fields in Brazil (Silva and Beltrão, 1999;Alvarenga Jr, 2012) but at a much lower proportion. The origin of H400, also known as the "white hybrid," is not clear, but seems to be closely related to the H11648 (Souza et al, 2018).…”