Roslinsky: Transfer of Pod Shatter Resistance from Yellow Seeded B. Napus and B. Napus to Canola

Date: March 2013
Term: 2 years
Status: Completed
Researcher(s): Dr. Sally Vail, Vicky Roslinsky, Agriculture and Agri-Food Canada, Saskatoon
SaskCanola Investment: n/a
Total Project Cost: n/a
Funding Partners: n/a

Project Summary

Although the majority of canola producers currently swath Brassica napus prior to combining, many producers would prefer to have the option to straight combine and therefore avoid the cost and time associated with swathing. Researchers at Agriculture and Agri-Food Canada conducted a pod shatter resistance study in 2011 and 2012 focusing on the genetic control and field analysis of pod shatter in yellow seeded B. napus in an attempt to improve shatter resistance in conventional canola. The results showed that pod shatter is a very complex trait controlled by many genes. Shatter reduction seems to be distinct from seed coat colour or fibre content suggesting shatter reduction from this source could be transferred into black seeded cultivars or hybrids.

The vast majority of canola producers currently swath Brassica napus prior to combining, which increases production and ecological costs and may affect seed quality due to higher chlorophyll content with pre-mature swathing or when the crop dries down too quickly. Producers would prefer to have the option to straight combine and therefore avoid the cost and time associated with swathing. Shatter of canola seed from pods as well as pod-drop are of concern to producers due to yield loss and contributions to weed seed banks for subsequent seasons volunteer control.

An Agriculture and Agri-Food Canada (AAFC) pod shatter resistance study focused on the genetic control and field analysis of pod shatter in yellow seeded B. napus in an attempt to improve shatter resistance in conventional canola. Based on previous observations at AAFC, yellow seeded B. napus has been identified as a potential source for improved pod shatter resistance in conventional canola. Little is currently known in terms of the genetic control of this trait. Researchers are using a molecular mapping approach to determine what is contributing to the observed reduction in shattering from the yellow-seeded lines.

Field experiments conducted in 2011 and 2012 at two AAFC sites near Saskatoon focused on phenotyping two doubled haploid mapping populations from crosses between low fibre yellow seeded lines with different conventional black seeded lines ('Yellow-Black' or YB lines). The sites were seeded about two weeks apart, comparing several doubled haploid YB mapping population lines, parental lines, a shatter susceptible check (AC Excel), additional yellow seeded lines and a commercial hybrid check. Three harvest treatments were compared: swathed plots at 60% pod colour turn (swath); direct combine at full maturity (straight cut) and direct combine one month after full maturity (late straight cut). In the 2012 trials, an early snowfall prevented a successful late straight cut harvest treatment.

The study showed that there are significant differences between shatter susceptible lines (DH12075 and Excel) and yellow-seeded lines and commercial checks. Researchers used the resulting values from the visual ratings from both seasons and the yield loss data from 2011 to explore the relationship between various seed-component related traits and shatter reduction. Other factors such as environmental conditions under certain situations and with some populations, plant stand, and flowering date/maturity seemed to play a role in the degree of pod shatter occurring.

As a result of the study, detailed genetic work and molecular mapping has been done and researchers are continuing to zero in on genes and molecular markers of interest. The results show that pod shatter is a very complex trait controlled by many genes. Shatter reduction seems to be distinct from seed coat colour or fibre content suggesting shatter reduction from this source could be transferred into commercial black seeded cultivars or hybrids.

Figure 1. Pod Shatter Field Trial. Source: AAFC.

Full Report PDF: Long report not available