Chlorophyll and nitrogen content in leaves of winter wheat at differentgenotypes and fertilization

摘要

The SPAD meter readings and N leaf content were evaluated in field and pot experiments with winter wheat (Triticum aestivum L.) at different genotypes and N fertilization. In the field experiment in the year of 1997/1998 five winter wheat genotypes (Ilona, PS 7/95, PS 19/94, SK 678-18, SK 656-2) were evaluated at 12 fertilization variants created by four N treatments (0, 30, 60, 120 kg N.ha(-1)) and three P treatments (0, 20, 40 kg P.ha(-1)). The SPAD meter readings were taken on 3 June at growth stage (GS) 42, on 11 June at GS 46, on 16 June at GS 49, and on 7 July at GS 79. Leaves for N determination were sampled at last three terms. With the same winter wheat genotypes as those in the field experiment in which genotype SO 1441 instead of PS 7/95 was included, a pot experiment was established with two N treatments (0 and 40 mg N.kg(-1) of soil). Plants were grown in a growth chamber under controlled environmental conditions: 16-hour photoperiod with irradiance of 480 mu mol.m(-2).s(-1) at dayight temperatures of 23/16 degrees C. Leaves were sampled and SPAD meter readings were taken on 28 January at GS 55, on 15 February at GS 68 and on 3 March at GS 75. Factors N fertilization, genotype, growth stage and interaction between them had significant effect on the chlorophyll (SPAD) and N content in leaves. N treatment increased SPAD values in the field experiment at the beginning of heading (N-0 = 50.09, N-120 = 54.84) as well as in the pot experiment (N-0 = 56.18, N-40 = 58.33) and also N leaf content tin the same order) (N-0 = 3.653%, N-120 = 4.440%, N-0 = 3.888%, N-40 = 4.337%). The higher N doses, the higher portion of SPAD meter readings and N leaf content in later growth stages in comparison to earlier ones. SPAD meter readings went down from GS 49 to GS 79 at N-0 to 49.7% (24.88/50.08), but at N120 in the same growth stages only to 77.6%. N leaf content in the same order went down to 42.8% (1.563%/3.653%) and to 62.6% (2.778%/4.440%). Genotypic differences in SPAD meter readings and N leaf content were the same or higher than among N treatments. The relationships between N leaf content and SPAD values were strong both in the field and pot experiments at variability dependent on N treatments (r = 0.975(++)) or dependent on genotypes (r = 0.982(++)). Equally high correlations were between N doses on one hand and SPAD meter readings (r = 0.952(++)) and N leaf content (r = 0.937(++)) on the other hand. In the field experiment strong positive correlations were found between SPAD value and N content in grain (r = 0.975(++)), and also N leaf content and N content in grain (r = 0.846). These results indicated that the above mentioned relations can be used in cultural practices and in breeding for quality and better utilization of N.