Relationships among Daily Flower Production, Length of the Flowering Period, and Seed Yield of Flax

Abstract

The number of flowers produced each day is easily determined for flax (Linum usitatissimum L.). An analysis of daily changes in flower production should reflect genetic, environmental, and edaphic effects on an important component of seed yield, namely fruits per area, because of the direct relationship between flower and fruit numbers in this crop. The objectives of this study were to develop techniques for analyzing flower count data for ‘Linott’ flax; to relate flower counts and their transformations to total flower production, length of flowering stage, and seed yield; and to relate weather data to the same characteristics. Flower production and seed yield varied markedly in seven field trials over 6 yr. Total flower count and length of flowering were closely correlated. Equations with high coefficient of determination were obtained for both by regression using easily obtained flowering measures as independent variables. Seed yield had high positive correlation to calendar dates of maximum daily flower count and last flower, but was not closely related to maximum daily flower count, total count, or length of flowering. Years when daily flower production rate increased rapidly with little lag phase were low in yield. High coefficients of determination for yield were obtained using relative flower count (flowers flower−1 d−1), calculated similarly to relative growth rate in plant growth analysis, and daily count (flowers m−2) for 1 to 4 d of the flowering period as independent variables. Regression of weekly mean air temperature, soil temperature, precipitation, and wind on yield also resulted in high coefficients of determination. It is concluded that the calendar dates of certain flowering events and how flowering rate changed with time were more important for seed yield in Linott than length of the flowering period.