Our objectives were to: i) identify quantitative trait loci (QTL) associated with grain yield, moisture, plant height and ear height in two maize (Zeal mays L.) crosses; ii) compare results from different methods of mapping QTL; iii) evaluate QTL x environment (QTLxE) interaction; iv) determine effect of identified QTL on multiple traits; and v) compare results with those in the Maize database. The genetic material consisted of 122 random S 5 lines from Va26xMo17 testcrossed to B73 and 95 random S 5 lines from B84xB73 testcrossed to Mo17. Testcrosses were evaluated for grain yield, plant height, ear height, and grain moisture in 6 environments. Restriction fragment length polymorphism (RFLP) data were obtained for 75 DNA probes for Va26xMo17 and 45 for B84xB73. Methods used to detect quantitative trait loci (QTL) included simple mapping using single factor analysis in SAS (SM), stepwise multiple regression (MR), simple interval mapping (SIM), and composite interval mapping (CIM). More QTL were identified in the Va26xMo17 cross than in B84xB73. This difference may have resulted from Va26xMo17 having more probes and more phenotypic data available and/or because of greater genetic diversity in the Va26xMo17 cross. For yield CIM and SIM both identified 6 significant QTL. Five of the six QTL identified by CIM were also identified by SIM. Using MR, 9 QTL were identified, 5 of which were in the same regions as those identified by CIM. Similar agreement between methods was found for plant and ear height. However, for grain moisture CIM identified nearly twice as many QTL as SIM or MR. More QTL were detected for plant height, ear height, and grain moisture than for grain yield. Some QTL for grain yield were also associated with QTL for moisture, plant height and ear height. Only one QTL for yield was in common between the Va26xMo17 cross and the B73xB84 cross. A small number of markers found associated with QTL were listed as associated with QTL for the same trait in the Maize database records. Although agreement between individual environments for identification of QTL was poor, QTL x environment interaction measured by CIM was not important.
|Number of pages||12|
|State||Published - Jun 19 2000|
- Composite interval mapping
- QTL x environment interaction
- Zea mays L.