Sunflower Production as Influenced by Plant Type, Plant Population, and Row Arrangement

Abstract

AbstractSemidwarf sunflower (Helianthus annuus L.) hybrids recently became available to producers. Information on the response of this plant type to different cultural practices is limited. Field studies were conducted at two locations in 1984, 1985, and 1986, to determine the effect of different row arrangements and plant populations on yield, yield components, and other agronomic traits of a semidwarf (SD) and a standard height (SH) sunflower hybrid. Plant populations evaluated were 35 000, 50 000, and 65 000 plants ha−1. Row arrangements evaluated consisted of (i) conventional rows, spaced 0.76 m apart, (ii) solid seeded rows, spaced 0.38 m apart, and (iii) twin rows, two rows 0.19 m apart on 0.76 m centers. A path coefficient method was used for yield component analysis. Analyses across environments indicated no statistical differences for yield among hybrids, plant populations, or row arrangements. Significant environment ✕ hybrid, environment ✕ row arrangements and environment ✕ arrangement ✕ population interactions on yield were found. The SH type outyielded the SD at all environments, although statistically significant differences were found in only four of the six environments. In general, plant population and number of seeds per head were the yield components having the greatest direct effect on yield. The direct response of plant population was masked by the negative effect of seeds per head and seed weight, resulting in a low coefficient of correlation. Harvest index of SH (36%) was statistically higher than for the SD (32%). The difference was due to the heavier receptacle of the SD. This indicates that possibilities exist to improve semidwarf genotype yield by reducing receptable weight.