During the process of maize seed production, in order to ensure the genetic purity of parental forms of hybrid maize, an important work performed is the removal of male inflorescences from plants on mother rows. Hand detasseling has high precision but is labor-intensive. Mechanical detasseling offers the possibility to cover large acreages in a short period of time, but the number of leaves removed has a varying influence on plant performance and seed yield. The aim of this study was to simulate three types of damages on plants similar to those induced through mechanical detasseling and to assess the effects for five inbred lines during the course of three years. Results show that when tassels alone were removed, the average seed yield decreased an average of 4–21%. When two leaves were removed with the tassel, yield decreased an average of 22–31%, while when plants were cut above the main ear, seed yield decreased an average of 31–66%. Environmental conditions influenced seed yield, especially high temperatures during flowering. Yield response to tassel and leaves removal varied between the inbred lines. Genotype controls maize ear and kernel characters, while environmental factors exercise a strong influence on seed yield, due to the succession of years with contrasting weather conditions in a key phenophase. Within the trend of full mechanization in agriculture, identification of inbred lines that cope better with plant damage can assist in optimizing seed production.

Carotenoids are important biologically active compounds in the human diet due to their role in maintaining a proper health status. Maize (Zea mays L.) is one of the main crops worldwide, in terms of production quantity, yield and harvested area, as it is also an important source of carotenoids in human nutrition worldwide. Increasing the carotenoid content of maize grains is one of the major targets of the research into maize breeding; in this context, the aim of this study was to establish the influence of some fertile cytoplasm on the carotenoid content in inbred lines and hybrids. Twenty-five isonuclear lines and 100 hybrids were studied for the genetic determinism involved in the transmission of four target carotenoids: lutein, zeaxanthin, β-cryptoxanthin and β-carotene. The analysis of carotenoids was carried out using high performance liquid chromatography using a Flexar system with UV-VIS detection. The obtained data revealed that the cytoplasms did not have a significant influence on the carotenoid content of the inbred lines; larger differences were attributed to the cytoplasm × nucleus interaction. For hybrids, the cytoplasmic nuclear interactions have a significant influence on the content of lutein, zeaxanthin and β-cryptoxanthin. For the cytoplasm × nucleus × tester interactions, significant differences were identified for all traits.

Maize occupies a significant place in the world agriculture. Yellow kernel maize contains mainly non-provitamin A carotenoids: lutein and zeaxanthin. The accumulation of provitamin A carotenoids is regulated by favourable alleles of lcyE and crtRB1 genes and could be used for the enhancement of these carotenoids in the maize grain through breeding. In this study, molecular screening of the Romanian germplasm was performed, looking for favourable alleles of the crtRB1 and lcyE genes, and the level of carotenoids was determined in a few selected lines. A number of 2746 inbred lines from seven research stations were subjected to a PCR amplification of crtRB1 and lcyE genes in order to identify the favourable alleles. It was selected 27 lines carrying the favourable alleles and nine lines with unfavourable alleles (four groups in total), from which total carotenoids, lutein, zeaxanthin, β-cryptoxanthin, β-carotene and retinol equivalents were determined by HPLC. Out of 2746 inbred lines analysed, 23.53% contained one or both genes with favourable alleles. The favourable allele of the crtRB1 gene was the most widespread (584 lines), followed by the lcyE gene (55 lines), while alleles favourable for both genes were detected in only 7 lines. Inbred lines with the favourable allele of the crtRB1 gene showed the highest levels of β-carotene and β-cryptoxanthin, while those with favourable allele of lcyE gene showed a high level of β-cryptoxanthin; the lines with favourable alleles for both genes had a level of β-carotene 60% higher than the lines with two unfavourable alleles.

In maize, local populations are the result of the mass selection made by the farmers, following especially the production characters. The expansion in culture of American maize hybrids resulted in an increase in grain yield, but also a reduction in the areas cultivated with local populations and their process of introgression with hybrids. In recent years, European breeders, but also Romanian breeders, have begun to pay attention to the collection of local maize germplas, in the hope that it will prove useful in future breeding programs. In Romania, there is relatively little data on the phenotypical and genetic diversity of maize germplasm of the first Cycle. Turda maize collection is mainly composed of more than 300 local populations (landraces); 70 synthetics/ composites, 3 varieties, and more than 1400 inbred lines. For a deeper knowledge of the first cycle maize germplasm, a number of 8 inbred lines developed from the local populations were tested for their general combining ability by crossing with four elite inbred lines. 42 inbred lines developed fromTransylvania local populations were studied by using 80 SSR markers. In this way, it was possible to classify the 42 inbred lines, especially in 4 groups of germplasms: W 153R, F2, Lo3, D 105. Both local populations and synthetics/ composites were on average the most divergent (%) in height of ear (range value 22.3; 24.9), the number of tassel branches (range value 27.1; 27.8), ear weight (range value 22.9;20.3) and grain weight (range value 21.7; 20.9), grain oil concentration (range value 12.7;14.3) and grain fiber content 18.3 to landraces as compare to synthetics/ composites range value 9.8. The grain oil, fiber, and ash content showed high variability among the genotypes. In this context, the traditional germplasm represents a good source of genetic variability to explore and may help to identify the most suitable materials for the development of more nutritiousfoods.The objectives of this study were: i) to evaluate the potential of maize TURDA germplasm according to its plant andear characters as well as grain quality content ii) to estimate the extent of phenotypical and geneticalvariability and iii) to formulate a selection criterion in a breeding program.