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Title: FLOWERING OF LESQUERELLA AS AFFECTED BY NITROGEN FERTILIZATION AND SEEDING RATE

Author
item Adamsen, Floyd
item Coffelt, Terry
item NELSON, JOHN - UNIV OF AZ, TUCSON

Submitted to: Industrial Crops and Products
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/1/2005
Publication Date: 6/1/2005
Citation: Adamsen, F.J., Coffelt, T.A., Nelson, J.M. 2005. Flowering of lesquerella as affected by nitrogen fertilization and seeding rate. Industrial Crops and Products. 21:293-307

Interpretive Summary: Erucic acid found in industrial rape and crambe can be used in industrial applications such as lubricants and for diesel fuel replacement. The edible form of rape oil is sold commercially as Canola, and most of it is imported from Canada and Europe. Traditionally, rape and crambe have been grown in northern climates as spring-planted crops. Because both of these plants are ecool season crops, they have potential in the Desert Southwest as alternatives to wheat in crop rotation plans and remove excess soil nitrogen following cotton. The objectives of the this study were 1) to determine if an automated method using images from a digital camera could be used to measure flowering in crambe and rape, and 2) to determine the effects of planting date on flowering patterns of crambe and two species of rape. The automated method of flower counting was able to distinguish between species, showed distinctive differences in flowering related to planting date, and showed potential for comparing reproductive efficiencie of crop lines. With regard to flowering dates, it took twice as long for flowering to start when grown in Arizona than in North Dakota and yields were lower as well. However, oil content was as much as 20% higher when grown in Arizona compared to North Dakota, which offsets the lower yields. The differences in plant growth, yield, and oil content are important because this will lead to development of better adapted varieties for the Desert Southwest. These research results will be of value to researchers, consultants, and farm managers.

Technical Abstract: Because both crambe and rape are cool season crops, they may have potential as winter rotational crops in the desert southwest of the United States. The objectives of this study were 1) to determine if an automated method using images from a digital camera could be used to monitor flowering in rape and crambe, and 2) to determine the effects of planting date on flowering patterns of two Brassica species and crambe. Nine cultivars of rape and one cultivar of crambe were planted at the Maricopa Agricultural Center on 10/21/97, 11/05/97, 11/21/97, and 12/17/97. Five of the rape cultivars were Brassica napus types and the remaining four were Brassica campestris types. One, R500, was an industrial rape and the others were edible or Canola types. Digital images of flowers were obtained using the same color digital camera periodically from 01/29/98, the beginning of flowering for date of planting (DOP) 04/01 through 04/16/98, the end of flowering of DOP4. The automated method for estimating a flowering index was able to detect differences between Brasicus species and cultivars. Each species had a distinctive flowering pattern that could be used for identification. These results indicate the potential of this method for comparing the reproductive efficiency of cultivars. Planting dates also affected the pattern and efficiency of flowering. Compared to results from farther north with spring planting dates, plant heights were greater, oil content was higher, seed weights were comparable, days to flowering were more than doubled and yields were lower. Based on recent literature, this is the first report of the number of days of flowering. This study was not detailed enough to determine the physiological basis for the differences in plant growth and development found.