SUMMARY
Two of the factors that determine the onion crop are the cultivar and denseness.The researches were done on two forms within the period 2005-007. The forms are: SC Oferta Bob SRL situated in the south of the country and SC Petrosu SA – Braila situated in the south-east of the country.A number of 12 cultivars and three densenesses have been experimental. The best Durch and Romanian cultivars were used: Exacta F1, Columbia F1, Vachera F1, Daytona F1, Manas F1, Talon F1, Helenas F1, Briliant, Ariana, Delicioasa, Leone and Diamant. Three densenesses were used: 450.000 plants/ha, 650.000 plants/ha and 850.000 plants/ha based on six row scheme on the bad. The irrigation was made by aspersion at SC Petrosu SA and the dripping at SC Oferta Bob.The crops were influenced both by cultivar and by the number of the plants/ha.The biggest crop has been obtained at the dripping irrigated variants with the biggest denseness (850.000 plants/ha) at hybrids Daytona F1, Vachera F1 and Columbia F1 (over 80 t/ha) at the Romanian cultivar Delicioasa (over 70 t/ha). Differences between these crops and those obtained at the 450.000 plants/ha denseness (54-58 t/ha) are very significant.The crops are lower with about 10 t/ha at the aspersion irrigated variants. And in this case both the cultivars and the denseness have a decisive influence on the crops as well. At the same time Daytona F1, Vachera F1 and Columbia F1 hybrids behaved the best by using the aspersion irrigation.Making a comparison between the crops obtained 15 years ago by using the same denseness but less performant cultivars and the crops obtained in the recent experiments, there have been observed that in the old experiments the crops didn’t increase over 40 t/ha. Whereas in the recent experiments the crops increased over 80 t/ha.As a result of the experiments that have been done we can conclude that, in order to obtain big and of good quality onion crops. It is compulsory that a part the other technological stages necessary to be used in this culture (soil selection, precursory cultures, soil preparation, setting up optimum period, culture maintenance, optimum harvesting moment) to be used cultivars especially performent hybrids and also densiness of over 850.000 plants/ha.