Oilseeds Physiology and Agronomy

Research Interests:

My current research is focused on better understanding the physiological limitations to productivity of oilseed crops (soybean, canola) in Canada. While yield determination is quite well studied for the major grain crops (wheat, corn), much less is known about the physiological basis of genetic improvement of Canada's oilseed crops. Modern approaches to plant breeding allow for the efficient and targeted selection of specific physiological traits. This approach offers great potential for rapid progress, but only if we know in advance which traits are desirable!

One goal of my research is to identify those morphological / physiological characteristics that can impart enhanced tolerance of abiotic stresses, such as drought, chilling and excessive heat. A related activity is the screening of available germplasm for useful variability in these traits. This research involves experimentation from the cellular level (where traits express themselves), to the single plant level (where selection occurs in breeding programs) to the crop canopy level (where the value of specific traits to crop performance must ultimately be evaluated).

In addition to the potential contribution to genetic improvement, better understanding the physiological basis of yield formation in these crops should lead to improved recommendations for agronomic practices.

Selected Publications:

Earl, H.J. (2003). A precise gravimetric method for simulating drought stress in pot experiments. Crop Science 43:1868-1873.

Earl, H.J. and R.F. Davis. (2003). Effect of drought stress on leaf and whole canopy radiation use efficiency and yield of maize. Agronomy Journal 95:688-696.

Earl, H.J. (2002). Stomatal and non-stomatal restrictions to carbon assimilation in soybean (Glycine max) lines differing in water use efficiency. Environmental and Experimental Botany 48:237-246.

Earl, H.J. and M. Tollenaar. (1999). Using chlorophyll fluorometry to compare photosynthetic performance of commercial maize (Zea mays L.) hybrids in the field. Field Crops Research 61:201-210.

Earl, H.J. and M. Tollenaar. (1998). Differences among commercial maize (Zea mays L.) hybrids in respiration rates of mature leaves. Field Crops Research 59:9-19.