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Gene Bank Developed by Induced Mutation for Selection
45-49Views:74Heterosis breeding in maize caused gene erosion by using uniform inbred lines. In order to strengthen the genetic base, we established a gene bank containing lines with broad genetic variability, resistance and adaptability. The maize gene bank is a result of our work in the past two decades.
The gene bank originated from treatments of maize seeds of hybrids and inbred lines with fast neutrons. The 1500 maize lines have great genetic variability which can be exploited after strict assessment and selection. As a result of the past several years, P 26, P 61 and P 62 lines have been released after DUS investigation in 2001. -
The effect of production area on the development of yield producing factors of maize (Zea mays L.) hybrids of different genotypes
67-72Views:129Maize yield amount development is determined by the given crop year and the genotype of the applied hybrid, but beside these also by the applied agrotechnical factors, in particular by sowing technology. The development of yield amount and yield producing factors of five maize hybrids of different genotypes has been studied in a small-plot field experiment by the application of different row spacings and plant density variants. The production of the individual plants shows decreasing tendency parallel to the increasing plant density, however, this decrement is compensated by the higher number of plants per unit production area. Individual plant production is determined by the development of yield producing factors, such as the length and the diameter of cobs, just as by the thousand seed weight – that were studied in the present research work as well.
In the present research work the decreasing row spacing resulted in a yield increment of 0.67 t ha-1 (4.53%) in 2013, while in contrast in 2014 yield was decreased by 1.75 t ha-1 (14.87%). The high amount of precipitation in March was determinant in 2013: it filled up the soil water stock and balanced the negative effect of the inadequate amount and distribution of precipitation during the vegetation period for the yield. Lower extent of yield increment (0.6 t ha-1) was registered in 2014 in case of the row spacing of 76 cm than in the previous year. In case of a row spacing of 45 cm the difference between the two crop years was 3.1 t ha-1. The highest impact on the yield production factors was found in all treatment combinations in case of the applied hybrid among the three studied treatment factors. In the crop year of 2014 the effect of plant density on cob diameter and thousand seed weight could be revealed as well. In case of the cob diameter significant difference was found between the plant densities of 70 000 and 90 000 plants ha-1, just as between the populations with densities of 50 000 and 90 000 plants ha-1. In case of the thousand seed weight significant differences could be found by the application of plant densities of 70 000 and 90 000 plants ha-1. The highest values of the studied yield producing factors were measured in case of the plant densities of 50 000 and 70 000 plants ha-1; increasing the plant density to 90 000 plants ha-1 resulted in rather decreasing values.
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Evaluation of the correlation between SPAD readings and absolute chlorophyll content of maize under different nitrogen supply conditions
121-126Views:362Currently, one of the most important objectives of agriculture is to maintain the principles of the sustainability. The use of precision technologies in agriculture belongs to this topic. The use of precision technologies is increasingly widespread in the cultivation of various agricultural crops, including maize. Sensing is an important part of these techniques. In our experiment we compared two methods: measuring relative chlorophyll content and the method of determine the extractable chlorophylls. The experimental plant was maize (Zea mays L.) and the measurements were performed at an early development stage (V8) of three genotypes. Three levels of nitrogen (0; 80; 160 kg ha-1) were applied during the experiment. The relative chlorophyll content was measured by SPAD-502 (Minolta, Japan) and a handheld GreenSeeker (Trimble, USA) device. The extractable total chlorophyll content decreased in parallel with the increased nitrogen level. The obtained SPAD values were diversified furthermore the NDVI values have not been changed for the effect of different nitrogen fertilization. In the early stages of development of maize, these parameters need to be complemented with other measurements to provide reliable information about the crops nitrogen status.