QTL mapping for chlorophyll content in maize

In order to explore the genetic basis for chlorophyll content in maize (Zea mays L.), a total of 189 F2 individuals derived from the single cross between the inbred lines A150-3-2 and Mo17 were used as mapping population. Four traits associated with chlorophyll content were measured at the trumpet stage and at the flowering stage. Total 32 QTLs were investigated on all the chromosomes except for chromosomes 6 and 10. There were 24 QTLs located on chromosomes 1, 2, 3, 5, 7, 8, and 9 at the trumpet stage. Six QTLs were investigated for chlorophyll-a content (chla), chlorophyll-b content (chlb), other chlorophyll content (chlc), and total chlorophyll content (chlz), respectively. QTLs for four traits were located in the same marker intervals in many cases. The distance among different QTLs of the four traits in the same marker intervals ranged from 0 to 2 cM. The four major QTLs for chla, chlb, chlc, and chlz at the trumpet stage, which explained 11.63%, 10.3%, 10.77%, and 11.51% of the phenotypic variance, respectively, were investigated between umc1098 and bnlg557 on chromosome 5. There were 8 QTLs located on chromosomes 4 and 5 at the flowering stage, with 2 QTLs for chla, chlb, chlc, and chlz, respectively. QTLs were investigated between umc1098 and bnlg557, which controlled the four chlorophyll content traits (chla, chlb, chlc, and chlz), at the trumpet stage and two chlorophyll content traits (chla and chlb) at the flowering stage. QTLs between umc2308 and bnlg386 for the four traits related to chlorophyll content were investigated only at the flowering stage.