Variation in Chlorophyll Content of Maize Lines and Hybrids1

Quantitative differences in chlorophyll, genetic implications, and the relationship of total chlorophyll to various agronomic characters were studied in 17 inbred lines and 24 single‐cross hybrids of maize (Zea mays L.). Differences occurred for total chlorophyll/g in fresh weight of leaf tissue, chlorophyll a;, chlorophyll b, visual chlorophyll ratings, Ca:Cb ratios, and yield/plant, both among inbreds and hybrids. Relationships were found in both inbreds and hybrids,respectively, for total chlorophyll to visual rating (∗0.76* and ∗0.69*, *significant at P −0.01) and for total chlorophyll to Ca:Cb ratio (∗0.91* and ∗0.84*). No relationships were detected between total chlorophyll and yield in grams of ear corn/plant. Thus, chlorophyll levels in these experiments were not a limiting factor for yield. Chlorophyll content of the hybrid was characteristically greater in all instances than the mean of the inbred parents. Results indicate that there can be heterosis for chlorophyll content and that the simplest explanation is the presence of more loci having a dominant or partially dominant gene in the hybrid than in either parent. There was a positive relationship between hybrids with high amounts of heterosis for yield and those with high amounts of heterosis for chlorophyll (r = 0.93*). Significant reciprocal effects for total chlorophyll and yield were obtained in two pairs of single‐cross hybrids.