CHLOROPHYLL CONTENT OF MAIZE HYBRID AND INBREDS AS INFLUENCED BY TWO LEVELS OF DENSITY AND NITROGEN

Abstract

A field experiment was undertaken on the Research Station of the Dept. of Field Crop Sci. of the College of Agric. / Univ. of Baghdad . This was to study chlorophyll content (CC) and disappearance in a cross of maize and its parents, and its relationships to hybrid vigor under two levels of N (150 and 300 kg/ha) and two population densities (35 and 70 thousands plant/ha). Near 75% silking , (CC) in the ear leaf was 20.4 and 23.6 mg /g for the parents, and 21.3 and 23.8 mg/g fresh weight for hybrid under 150 and 300 kg N/ha , respectively with the density 35 thousands plant/ha. Whereas, at the higher density (70,000 ppha), the values became 17.2 and 18.8 for the parents, and 19.2 and 19.7 mg/g fresh weight for the hybrid, for the two levels of N, respectively and D2. However, at physiologic maturity, at higher density and N, (CC) values in the ear leaf became; 15.8 mg/g as average of parents, and 17.4 mg/g for the hybrid. This shows the higher level of (CC) in the hybrid and its stability at maturity .Higher nitrogen (150 to 300 kg N/ha) increased leaf area duration. The hybrid gave wider leaf area and higher chlorophyll content compared to its parents. One of the features of hybrid was the early transition from vegetative to reproductive stage compared to its parents. So, the hybrid produced 508 kernal / ear , while the inbreds gave 365 kernal /ear. Process of grain filling period and maturity depended on system capacity constant (SCC). The hybrid gave 47% HI compared to 31% for the inbreds. This led the hybrid to produce grain yield 11.98 t/ha and the inbreds 7.3 t/ha . The conclusion from results indicate that hybrid stability of (CC) in the leaf at maturity led to increased TDM and faster transition from vegetative to reproductive stage ; higher number of kernel /ear , and the higher grain yield in unit of area.