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Ontario Grain Farmer Magazine

Selecting for stress tolerance in oat

Principal Investigator: A. R. McElroy

Research Institution: PhytoGene Resources Inc.

Timeline: April 2019 – March 2021   

Objectives:

  • Develop measures of late-season stress using profiles of grain plumpness in individual panicles.
  • Evaluate the potential to predict plot yield using grain-fill parameters related to stress tolerance.
  • Evaluate elite lines using plot and panicle data to identify superior candidates for cultivar registration.

Impacts:

  • The development of effective protocols to select for tolerance to late-season stresses will provide an important new tool to oat breeders for developing high-yielding, stable oat cultivars.
  • Profitability for grain producers will be enhanced through the registration of elite, stress-tolerant lines identified in this study.
  • Stress tolerance will inevitably increase grain quality, particularly TKW and test weight and therefore help producers access the more profitable milling market.
  • The value of oat as a rotational crop is well recognized and increased profitability through the use of stress-tolerant, stable cultivars will help maintain oat as a viable cropping option.

Scientific Summary:

Environmental stresses affect oat yield, yield stability and grain quality.  In conditions of severe mid-season drought, yields can be reduced by a third and low test weight can render the crop unsuitable for milling.  The best approach to solving this problem is through plant breeding, selecting cultivars with good stress tolerance in order to maintain higher yields each year and to ensure that test weight is always high enough for the premium milling market.  The significant improvements in corn yield and yield stability have been attributed in large part to breeding for stress tolerance over the past decades. In oat, this approach is hampered by difficulties in measuring specific stress effects, given the inherent variability of kernel size within a panicle. Effective selection protocols are needed in order to breed for stress tolerance.

This project will build on previous studies which analyzed grain fill patterns in individual oat panicles. Early-season stresses were found to affect two important yield determinants, the number of kernels set and the proportion that fail to develop any groat at all.  Measurement of mid- and late-season stresses – often heat and drought – is difficult because the grain fill period is not uniform within a panicle; kernels at the top develop before those at the lower panicle nodes. The pattern of kernel mass distribution is fairly constant among non-stressed plants, regardless of inherent differences in average mass.  This pattern is significantly altered by stress, and measures to quantify those effects were developed. Kernel plumpness is closely related to mass but can be measured more rapidly. The goal is to develop an effective protocol for stress tolerance selection through analyses of grain fill based on kernel plumpness.

External Funding Partners:

Cribit Seeds

Crop Development Centre, University of Saskatchewan