Mapping QTLs for grain yield and yield components under high and low phosphorus treatments in maize (Zea mays L.)

A set of 210 F2:3 families developed from 5003(107) and 178 were used to identify quantitative trait loci (QTL) under high and low phosphorus treatments at Taian and Yantai. Six agronomic traits, including GY, 100KW, EL, RN, KN and ED were evaluated. A genetic map comprising 207 SSR markers spanned 1755.1 cm in length with an average interval of 8.48 cm between adjacent markers. A total of 69 QTLs were identified for the six traits at two sites. Thirty-six distinct QTLs were identified from Taian, in which 7 out of 36 for GY, 7 for 100KW, 5 for EL, 5 for RN, 6 for KN and 6 for ED, while 33 distinct QTLs were identified at Yantai, in which 6 out of 33 for GY, 5 for 100KW, 5 for EL, 7 for RN, 5 for KN and 5 for ED. In addition, three stable common loci crossing the two phosphorus treatment sites are in the interval umc2215–bnlg1429, umc1464–umc1829 and umc1645–bnlg1839 were detected on chromosome 1, 5 and 10. Our results suggest the presence of these QTLs may contribute to fine-mapping, identification of candidate genes and MAS strategies for maize improvement purposes under phosphorus deficiency combining traditional breeding approaches.