Yields of ns maize hybrids from different breeding periods

Abstract

Within maize breeding program at the Institute of Field and Vegetable Crops Novi Sad, Serbia, there have been seven distinct breeding cycles spanning from the mid-1960s. Each cycle is characterised by introduction of new hybrids with higher genetic yield potential. Breeding cycles were defined based on the period of hybrid introduction into production and the growing areas. In this study we analysed grain yield and moisture percentage in grain of five maize hybrids, namely NS 606, NS 640, NS 6010, NS 6030 and NS 6140, which are the representatives of the third, fourth, fifth, sixth and seventh breeding cycles. Seed of hybrids which are representatives of the first and second breeding cycles, namely NS 802 and NSSC 70, could not be produced because their parent inbred lines have lost their authenticity. According to the results of the combined ANOVA, significant differences (P<0,001) in grain yield were found among hybrids representatives of various breeding cycles and various environments, while the interaction cycle/ environment was found to be insignificant. A linear increase of yield by 0.44 t ha-1 (expressed by coefficient of linear regression) was found between individual breeding cycles. Since one breeding cycle lasts for approximately 7 years, average grain yield increase in maize from the third to the seventh breeding cycle was found to be 63 kg ha-1 per year.

Keywords

• maize
• grain yield
• selection cycles
• genetic gain