Doubled haploid technology is a feasible, fast, and cost-efficient way of producing completely homozygous lines in maize. Many factors contribute to the success of this system including the haploid induction rate (HIR) of inducer lines, the inducibility of donor background, and environmental conditions. Sixteen inducer lines were tested on eight different genetic backgrounds of five categories in different environments for the HIR to determine possible interaction specificity. The HIR was assessed using the R1-nj phenotype and corrected using the red root marker or using a gold-standard test that uses plant traits. RWS and Mo-17-derived inducers showed higher average induction rates and the commercial dent hybrid background showed higher inducibility. In contrast, sweet corn and flint backgrounds had a relatively lower inducibility, while non-stiff stalk and stiff stalk backgrounds showed intermediate inducibility. For the poor-performing donors (sweet corn and flint), there was no difference in the HIR among the inducers. Anthocyanin inhibitor genes in such donors were assumed to have increased the misclassification rate in the F₁ fraction and, hence, result in a lower HIR.

Doubled haploid (DH) technology in maize takes advantage of in vivo haploid induction (HI) triggered by pollination of donors of interest with inducer genotypes. However, the ability of different donors to be induced—inducibility (IND), varies among germplasm and the underlying molecular mechanisms are still unclear. In this study, the phenotypic variation for IND in a mapping population of temperate inbred lines was evaluated to identify regions in the maize genome associated with IND. A total of 247 F_2:3 families derived from a biparental cross of two elite inbred lines, A427 and CR1Ht, were grown in three different locations and Inclusive Composite Interval Mapping (ICIM) was used to identify quantitative trait loci (QTL) for IND. In total, four QTL were detected, explaining 37.4% of the phenotypic variance. No stable QTL was found across locations. The joint analysis revealed QTL × location interactions, suggesting minor QTL control IND, which are affected by the environment.

Maize is an essential crop for global food security, providing vital nutrients to billions of people. Its adaptation to climate challenges requires the development of productive and resilient varieties using both conventional and molecular breeding methods. Polyploidy significantly contributes to genetic diversity, with effects such as increasing plant organ size, reducing the impact of harmful mutations, and enhancing heterosis. The aim of this research was to evaluate the morphological and productive characteristics of diploid and tetraploid maize lines under polyfactorial experimental conditions. The study was conducted during the 2023-2024 period on the experimental field of the Faculty of Agricultural, Forestry, and Environmental Sciences at the Technical University of Moldova, on a typical chernozem soil under irrigated conditions. The biological material included three maize lines at both diploid and tetraploid levels. The analyzed parameters were plant height, ear insertion height, leaf size, panicle length, number of branches, and yield. The data obtained were statistically analyzed using the Fisher polyfactorial test. The factors investigated were year of research, ploidy, genotype, and replication. The experimental results showed that genotype and ploidy are the main determinants of morphological and agronomic trait variation, significantly influencing (p less than 0.05) plant height, leaf size, and panicle architecture. Environmental factors, especially the year of the experiment, had a variable impact, mainly affecting leaf and panicle size, but with a limited effect on yield. The interactions between genotype, ploidy, and the year of the experiment highlight the complexity of these influences on plant development. Their significance suggests that breeding strategies should consider optimal genotype-ploidy combinations to obtain stable and high-yielding varieties.

The development and use of rapid methods to control the genetic purity of seed material contributes to ensuring the quality of hybrid maize seeds. The purpose of the research was to systematize the main stages of preparation and modeling of electrophoretic passports for 65 local maize hybrids from different maturity groups and their 108 parental lines. The initial electrophoretic spectra of the storage protein of maize seeds (zein) were obtained by the electrophoresis method on polyacrylamide gels in acidic medium according to the national standard SM 233:2003. The analysis of the spectra and the obtaining of the passports was carried out in the „FOREZ-2” program. As a result, the main stages of biochemical preparation, digital creation and modeling of electrophoretic passports for 37 simple, 2 modified, 23 trilineal, 2 double and one multilineal hybrids, were experimentally argued and successively analyzed. The presented results will simplify the interpretation and efficiency of their use both for commercial purposes and in the research process. The proposed principles have a great potential for increasing the accuracy and expanding the possibility to expressly perform an objective diagnosis of the genetic purity and the level of hybridity of certified maize seed lots. Elaborarea și utilizarea metodelor rapide de control al purității genetice a materialului semincer contribuie la asigurarea calității semințelor de porumb hibrid. Scopul cercetării a constat în sistematizarea principalelor etape de pregătire și modelare a pașapoartelor electroforetice pentru 65 de hibrizi autohtoni de porumb din diferite grupe de maturitate și cele 108 linii parentale ale acestora. Spectrele electroforetice inițiale ale proteinei de rezervă a semințelor de porumb (zeina), au fost obținute prin metoda electroforezei pe geluri de poliacrilamidă în mediu acid conform standardului național SM 233:2003. Analiza spectrelor și obținerea pașapoartelor s-a realizat în programul „FOREZ-2”. În rezultat, au fost argumentate experimental și analizate succesiv principalele etape de pregătire biochimică, crearea în format digital și modelare a pașapoartelor electroforetice pentru 37 hibrizi simpli, 2 hibrizi simpli modificați, 23 hibrizi trilineali, 2 hibrizi dubli și un hibrid multilineal. Rezultatele prezentate vor simplifica interpretarea și eficiența utilizării acestora atât în scopuri comerciale, cât și în procesul de cercetare. Principiile propuse au un mare potențial pentru sporirea exactității și extinderea posibilității de a efectua expres o diagnosticare obiectivă a purității genetice și nivelului de hibriditate a loturilor de semințe de porumb certificat.

The article presents an analysis of the stage-by-stage use of the protein electrophoresis method (as a key method of protein chemistry) in the selection and seed production of maize for the period 1988-2023 in the Republic of Moldova. The possibility of using a set of methodological developments (electrophoresis method and computer modeling principles) on a large volume of maize breeding and genetic material has been experimentally substantiated. This methodological complex helps to solve two important problems: the problem of exporting seeds of Moldovan breeding hybrids of maize and for a wide range of research work in the field of genetics and selection and seed production of Zea mays L. The analysis of the recent year’s results allowed the authors of this article to focus on the development and creation specifics of a catalogue of electrophoretic passports of new generation maize hybrids. The authors consider this catalog as a serious argument for the effectiveness of introducing modern methods of biochemical genetics and computer technologies into agronomic practice, which can be used successfully at the national and international levels. В статье изложен анализ поэтапного использования метода электрофореза белков (как ключевого метода белковой химии) в селекции и семеноводстве кукурузы за период 1988-2023 в Республике Молдова. На большом объеме селекционного и генетического материала приведены экспериментальные доказательства целесообразности применения методологии комплексного использования метода электрофореза и принципов компьютерного моделирования как для проблемы экспорта семян гибридов кукурузы молдавской селекции, так и для широкого спектра научно-исследовательских работ в области генетики, селекции и семеноводства Zea mays L. В качестве серьезного аргумента эффективности внедрения в агрономическую практику современных методов биохимической генетики и компьютерных технологий авторы акцентируют внимание на специфике разработки и создания каталога электрофоретических паспортов районированных гибридов кукурузы нового поколения, с целью его использования на национальном и международном уровне.