YIELD OF COOL-SEASON SOYBEAN LINES DIFFERING IN PUBESCENCE COLOR AND DENSITY

Soybean [Glycine max CL.) Merr.] pubescence color may affect yield in cool-season soybean growing areas. The objective of this research was to examine the interaction of tawny (T) and gray (G) pubescence color with dense (D) and normal (N) pubescence density on seed yield. Lines differing in pubescence color and density were created from crosses wi th eight soybean cultivars adapted to Maturity Group 00 and 0 conditio ns. Within each cross, quadruplets were selected that had the four pub escence types: TD, TN, GD, and GN. These Lines were evaluated for yiel d across 4 yr at Ottawa, Canada. Lines with gray pubescence had from 7 .6 to 27.7% higher yields than those with tawny pubescence in years re ceiving >2664 crop heat units (CHU) during the growing season. In a ge ar receiving <2664 CHU, soybean Lines with tawny pubescence had 9.3% h igher seed yields than those with gray pubescence. The interaction bet ween pubescence color and seasonal temperature was similar among lines of diverse genetic background. Tawny lines with dense pubescence had from 3.1 to 10.6% higher yields than tawny lines with normal pubescenc e when the seasonal precipitation was <360 mm. In gray lines, changing pubescence density did not consistently affect seed yields. Soybean p ubescence color did affect seed yield and should be considered when br eeding for cool-season regions.