Ethyl Methanesulfonate as Inductor of Somaclonal Variants in Different Crops

Ethyl methanesulfonate is a chemical mutagen,which is currently being used in plant breeding,to increase genetic variability in genes of agronomic interest,of species useful in agriculture.It primarily causes single base point mutations by inducing guanine alkylation,resulting in GC to AT transitions.Its effect is different between clones of a genotype and between genotypes of the same species.This review presents the results obtained in recent research,where its effect on plant tissues,callus,and cells in suspension has been evaluated.Changes in the phenotypic expression of somaclonal variants were reported,involving morphology,production of secondary metabolites,changes in metabolic routes of resistance,tolerance to stress,increased seed yield,among others.In addition,this review compiles the doses and guidelines to consider before using this mutagen,which can serve as a guide for future trials in deciding the response variables,the type of plant explants and the selection of the study model.Mutant lines have allowed plant breeders to have a collection of plants with different characteristics,in places where the cultivar does not have its center of origin.It is important to note that it is still necessary to continue evaluating the heritability of mutations and their behaviour in the environment where they will be established,in order to obtain new varieties of plants that can be cultivated with uniformity in their genetic response.

Conventional digital cameras as a tool for assessing leaf area index and biomass for cereal breeding

Affordable and easy-to-use methods for assessing biomass and leaf area index （LAI） would be of interest in most breeding programs. Here, we describe the evaluation of a protocol for photographic sampling and image analysis aimed at providing low-labor yet robust indicators of biomass and LAI. In this trial, two genotypes of triticale, two of bread wheat, and four of tritordeum were studied. At six dates during the growing cycle, biomass and LAI were measured destructively, and digital photography was taken on the same dates. Several vegetation indices were calculated from each image. The results showed that repeatable and consistent values of the indices were obtained in consecutive photographic samplings on the same plots. The photographic indices were highly correlated with the destructive measure-ments, though the magnitude of the correlation was lower after anthesis. This work shows that photographic assess-ment of biomass and LAI can be fast, affordable, have good repeatability, and can be used under bright and overcast skies. A practical vegetation index derived from pictures is the fraction of green pixels over the total pixels of the image, and as it shows good correlations with all biomass variables, is the most robust to lighting conditions and has easy interpretation.