Relationships and Uses of Yield Components in Safflower Breeding1
- G. H. Abel2
An understanding of the interrelationships of growth characters is needed to improve breeding of safflower, Carthamus tinctorius L. The objectives of the study were to evaluate five plant characters and four seed characters as units of selection and to determine the optimum combination of years, locations, and dates of planting for testing cultivar performance.
Indirect yield components (plant height∕plot, canopy depth∕plant, canopy width∕plant, and head diam∕plant) were intercorrelated. They were also correlated to seed yield and to seeds∕head but with the exception of head diam∕plant they were not correlated to seed weight. The direct yield components (heads∕area, seeds∕head, and seed weight) were not intercorrelated but they were all correlated to seed yield.
In several tests involving seven cultivars, variance components were usually significant for plant height, heads∕section, and seed weight and usually nonsignificant for canopy depth, head diameter, and seeds∕head.
Cultivar × date of planting and cultivar × location interactions were generally nonsignificant. However heads∕section, seeds∕head, and seed weight showed significant interactions of cultivars with location and date of planting and made it evident that a single year's testing did not adequately evaluate these effects. Cultivar × year interactions were not significant when the data from only one location, Mesa, were analyzed. However when all three locations were considered, some significant interactions appeared.
Expected variances of varietal means for heads∕section, seed yield∕section, and seed yield∕plot were calculated for all combinations of environments and also extrapolated to six replications. Expected variances were virtually identical for the second and third years and second and third planting dates. Satisfactory precision for these characters was obtained for the cultivars tested using the combination of 2 years, two locations, two dates of planting, and four replications.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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