Identification of double-haploid maize plants one generation after the chromosomes doubling

Abstract

The objectives in the present work were to identify maize double haploids one generation after chromosome duplication through the evaluation of phenotypic characteristics in thr field, flow cytometry and molecular markers SSR. The seeds used in the present study were obtained from a cross between four simple hybrids (DKB393, GNS 3225, GNS 3264, GNS 3032) and the KEMS inducer of gymnogenetic haploidy, used as a male parent. Seeds from this crossing were selected according to the R-Navajo marker and those considered haploid, were submitted to two different chromosome duplication protocols. Plants that survived to the chromosome duplication protocols were acclimatized in greenhouse and later transplanted to the field. After self-fertilization of the DH0 plants, the DH1 seeds obtained were seeded in the field, divided into treatments according to the parental and duplication protocols. At the vegetative stage V4 of the DH1 seedlings, leaf tissue samples were collected to identify ploidy via flow cytometry and DNA analyzes using microsatellite markers. These results were confronted with the morphological characteristics of the future DH1 plants developed in the field, evaluated with the use of descriptive tools. Statistical analyzes were performed using the generalized linear modeling approach and the exploratory and inferential analyzes of datas, by the use of graphical resources, barplot and boxplot. For the analysis of variance, were used the Student-Newman-Keuls test, and the Pearson's correlations. It was not observed uniformity of phenotypic characteristics of plants subjected to duplication protocols in the field and the use of descriptive tools in the morphological analysis of adult maize plants must be done carefully to avoid the wrong classification of determined genotypes related to the ployd. Flow cytometry must be used as screening in the identification of possible DH´s and the molecular markers SSR can be used to prove the genetically inherited KEMS lineage and also to identify the double-haploid corn plants.