ARTICLE 1 – opinion

MORE THAN A CENTURY OF CYTOGENETIC STUDIES IN CHILEAN PLANTS: HOW MUCH HAVE WE PROGRESSED?

MÁS DE UN SIGLO DE ESTUDIOS CITOGENÉTICOS EN PLANTAS CHILENAS: ¿CUÁNTO HEMOS PROGRESADO?

Jara Seguel P., Palma Rojas C.

An overview is provided on the cytogenetic of Chilean plants, highlighting information gathered from more than a century of work carried out by foreign and national researchers who have contributed to the study of native species. We briefly present the progress made to date and also emphasize some strategies that, in our opinion, could spur further advances in this second century of cytogenetic studies in Chilean plants.

Key words: Cytogenetics, cytogenomics, Chilean plants. 
Doi: 10.35407/bag.2021.32.01.01
Language: English

ARTICLE 2 – opinion

Camadro E.L., Rimieri P.

Plant genetic resources for food and agriculture are ex situ conserved in germplasm banks as samples (accessions) of natural or naturalized populations, either as the originally sampled propagules (mainly seeds) or their multiplications. The premises underlying ex situ conservation are that (a) it is the safest and cheapest alternative for germplasm preservation for future generations and (b) accessions are representative of the genetic diversity encountered in nature. In the past decades, ideas, alternatives and considerations have been put forward on the topic, and protocols have been devised for plant germplasm sampling, conservation and multiplication. However, limitations in the management efficiency of germplasm banks have been pointed out by international organizations. In our opinion, germplasm banks in general need to revise their functioning and management at the light of principles and methods of Genetics. To that end, it is necessary to consider the reproductive biology of higher plants -whose genetic consequences at both the individual plant and the population levels are not always either fully understood or taken into account in devising the protocols-, the genetic structures of wild and cultivated populations, and the course of the genetic material in the populations. In this paper, we discuss the three topics and provide an example of a national forage breeding program, from germplasm bank accessions as the germplasm of origin to the obtainment of commercial cultivars. Finally, we present a proposal as a base for discussion among curators, researchers and breeders.

Key words: accessions, breeding, genetic resources, germplasm banks, population genetics 
Doi: 10.35407/bag.2021.32.01.02
Language: English

ARTICLE 3 – research

MULTI-TRAIT MODELS FOR GENOMIC REGIONS ASSOCIATED WITH MAL DE RÍO CUARTO AND BACTERIAL DISEASE IN MAIZE

MODELOS MULTIVARIADOS EN LA BÚSQUEDA DE REGIONES GENÓMICAS PARA RESISTENCIA A MAL DE RÍO CUARTO Y BACTERIOSIS EN MAÍZ

Ruiz M., Rossi E.A., Bonamico N.C., Balzarini M.G.

Maize (Zea Mays L.) production has been greatly benefited from the improvement of inbred lines in regard to the resistance to diseases. However, the absence of resistant genotypes to bacteriosis is remarkable. The aim of the study was to identify genomic regions for resistance to Mal de Río Cuarto (MRC) and to bacterial disease (BD) in a diverse maize germplasm evaluated in the Argentinian region where MRC virus is endemic. A maize diverse population was assessed for both diseases during the 2019-2020 crop season. Incidence and severity of MRC and BD were estimated for each line and a genome wide association study (GWAS) was conducted with 78,376 SNP markers. A multi-trait mixed linear model was used for simultaneous evaluation of resistance to MRC and BD in the scored lines. The germplasm showed high genetic variability for both MRC and BD resistance. No significant genetic correlation was observed between the response to both diseases. Promising genomic regions for resistance to MRC and BD were identified and will be confirmed in further trials.

Key words: maize disease; genome wide association study; SNP; multi-trait model
Doi: 10.35407/bag.2021.32.01.03
Language: Spanish

ARTICLE 4 – research

Del Medico A. P., Tenaglia G., Lavalle A. L., Vitelleschi M. S., Pratta G. R.

In an asexually reproducing hybrid such as banana (Musa spp.), the assessment of clones in the short term is limited because replications are frequently unavailable in the proper number. The aim of this work is to propose the Multiple Factor Analysis of Mixed Data (MFAmix) as a tool for establishing objective criteria to identify banana clones that preserve variability for qualitative and quantitative variables. In the long term, the aim is the development of a banana germplasm bank. MFAmix was applied on a population composed of 124 banana clones collected from different farmers’ fields and four controls. Two groups of variables related to the agronomic aptitude of the clones were evaluated, one composed of nine quantitative variables, and the other, composed of three dichotomous qualitative variables. A Selection Index (SI) was built from the MFAmix coordinates in order to rank the clones and select a subset that allows to preserve the existing genetic variability. The first two axes of MFAmix explained a 49.47% of the total data variability. The set of the banana clones was successfully characterized based on quantitative and qualitative variables. In the long term, the creation of a banana germplasm bank should consider the height and diameter of the plant, the rachis bunch weight and the hands weight, and the qualitative variable plant leafiness.

Key words: asexual hybrid, collection of germplasm, multivariate analysis, Musaceae.
Doi: 10.35407/bag.2021.32.01.04
Language: English

OBITUARY

1950-2021

OBITUARY

1929-2021