Use of chromosomal translocations to locate genes in maize for resistance to high‐pH soil

Abstract

A maize inbred line (Purple 3036–1) with tolerance to nigh‐pH soils was crossed with susceptible homozygous translocation stocks that marked all chromosome arms, except the short arms of 3 and 7 and the long arm or 10. F₂’s and test crosses to the appropriate translocation stocks were used in the analysis.

A randomized complete block design with eight replications was used to evaluate the height difference between paired rows grown from normal and mutant seeds. Six replications were grown on land that had formerly been a creek bed and ranged in pH from 8.2 to 9.1 at 0 to 20 cm. Two replications were grown in a nearby field with a pH of 7.9 at 0 to 20 cm as a control. The treatment design was a split‐split‐plot with the translocation being the whole plot, the F₂ and test cross involving the same translocation as the subplot, and the normal and mutant (sugary or waxy) rows as the sub‐subplot.

The results were evaluated using a t‐test that combined data from both the F₂ and the test cross of a particular translocation. Genes for tolerance to lime‐induced stunting were located on the short arms of chromosomes 2, 4, and 10 and on the long arms of 3, 6, and 8. The largest differences were demonstrated by progenies testing the long arms of chromosomes 3 and 8.

Key words:

• iron
• Fe
• lime‐induced chlorosis
• calcareous‐soil
• iron‐deficiency