The aim of this study was to investigate the effect of irrigation and the amount and timing of application of nitrogen basal and top dressing fertilisation on the chlorophyll concentration (SPAD) and grain yield of maize hybrids of different genotypes on chernozem soil with lime deposits in an extreme dry year (2022). It was shown that moisture deficit impaired the uptake and utilisation of fertilisers by plants. The SPAD value was not affected by fertiliser application in the non-irrigated version, with the expection of the Fornad hybrid (V12180, p<0.05). In the irrigated version, all three hybrids reached the maximum value (p<0.05) under the A60 treatment. Chlorophyll concentration was extremely low at all developmental stages due to drought. The maximum SPAD value (p<0.05) (43.2–48.8) was reached at the V8 phenophase in both the non-irrigated and irrigated versions, and then decreased significantly (10.5–15.4) by the harvesting period. A difference in SPAD value was detected between the hybrids at the early vegetation period, between Armagnac and Merida (p<0.05), where Merida had higher SPAD values in both versions. Yield was increased (p<0.05) when N was applied as a basal fertiliser (A120) at 120 kg/ha, except for the non-irrigated version of the Merida hybrid, which is indicative of the drought tolerance of the hybrid (41.0 SPAD value, V6150 treatment, 10.060 t/ha). Chlorophyll content is sensitive to moisture deficit, so that chlorophyll degradation started early in the growing season, irrigation delayed this process, which was reflected in grain yield depending on genotype and fertiliser treatment. The effect of irrigation was greatest in the treatment V6150 (5.267 t/ha) of the Armagnac hybrid, V690 (4.075 t/ha) of the Fornad hybrid and A120 (4.160 t/ha) of the Merida hybrid. It was found that, under specific conditions (extreme drought), chlorophyll concentration is an effective aid in selecting drought tolerant hybrids. Furthermore, under natural rainfall conditions, in extreme drought years, the early maturity Merida (FAO 380) hybrid can be recommended for cultivation with the V6150 treatment, while the medium maturity Armagnac (FAO 490) hybrid can be recommended for cultivation by applying the A120 treatment, if irrigation is possible. The one-year results of the field experiment are not sufficient to make a definite conclusion, but such an extreme drought year has not occurred in Hungary for four decades.