YIELD PERFORMANCE OF UPRIGHT-LEAVED SELECTIONS OF WINTER WHEAT IN NARROW ROW SPACINGS

Abstract

Short-strawed, upright-leaved selections of winter wheat were compared with a tall, droopy-leaved check variety in wide (22.8- and 17.8-cm) and narrow (11.4- and 8.9-cm) row spacings at three seeding rates, to determine the best row width for highest grain yields and to determine whether an entry × row-spacing interaction could be measured. All entries produced more grain from narrow than from wide rows, in both years (1964 and 1966) and at all three seeding rates. This increase averaged 12.6% in the selections and 6.9% in the check variety. Highest yields were obtained at a seeding rate of 134 kg/ha, and in all cases the check variety outyielded the selections. The test demonstrated that higher grain yields were produced by a better spatial arrangement achieved by narrow row spacings, and that yield deficiencies in upright-leaved types could not be compensated for by a heavier seeding rate. While upright-leaved selections showed a greater increase in grain produced than did the check variety, no interaction with row spacings could be obtained statistically. It is suggested that lines which yield as high as check varieties in standard row-spacing tests (wide) may outyield the standard tall, droopy-leaved varieties in narrow rows. Short-strawed, upright-leaved selections emerging from the winter wheat program should therefore be tested in narrow row spacings so that these lines can express their full potential.