Assignment of the Y17 Locus to Classical Soybean Linkage Group 14

Abstract

The classical genetic map of soybean [Glycine max (L.) Merr.] remains at a primitive stage of development relative to the map of other crops. This study was undertaken to augment the information base needed for a more comprehensive classical map. The cultivar Minsoy, which carries the dominant allele Pb that conditions a sharp pubescence tip, was crossed to the genetic type T162, which carries the recessive allele yl7 that conditions chlorotic foliage. The F2 seedlings were classified for sharp vs. blunt pubescence tip and green vs. chlorotic foliage. the chi‐square for linkage partitioned from the total chi‐square was significant and recombination value of 27% was calculated for the y17 and pb loci. Because a recombination value of 27% had previously been reported for pb and the y9 gene, which also conditions foliar chlorosis, an allelism test was conducted to test for the allelism of y17 and y9 by hybridizing genetic type T135, which carries the recessive allele y9, with T162, which carries the recessive allele y17. The F1 hybrids had normal green foliage indicating that y17 and y9 were separate loci. To determine whether y9 and y17 were on the same side or opposite sides of the Pb locus, the F2 of the T135 ✕ T162 cross was tested with chi‐square for fit to a 9:7 ratio or a 1:1 ratio for green:chlorotic foliage. The F2 segregation data fit the 1:1 ratio indicating that the Y17 and Y9 loci were both on the same of the Pb and in close proximity.