Browsing by Author "Cook, Jason"

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Relationships between roots, the stay‐green phenotype, and agronomic performance in barley and wheat grown in semi‐arid conditions
(Wiley, 2022-01) Williams, Jessica L.; Sherman, Jamie D.; Lamb, Peggy F.; Cook, Jason; Lachowiec, Jennifer A.; Bourgault, Maryse
Stay-green is a phenotype that crop breeders could use to improve drought adaptation. It increases the duration of grain fill in several species including barley (Hordeum vulgare L.) and wheat (Triticum aestivum L.), maintaining yield in semi-arid conditions. Evidence from controlled environment experiments suggests a connection between stay-green and root systems. These belowground structures are understudied and thus represent opportunity for crop improvement if relationships to agronomics can be understood. Minirhizotrons facilitate study of these relationships by allowing repeated nondestructive root measurements in field conditions. However, this is time-consuming, and proxies would be useful for increasing throughput capacity of root research. Here we present results from field trials with minirhizotrons in a semi-arid environment, as well as greenhouse seedling assays conducted on stay-green and non-stay-green barley and wheat lines. In barley, stay-green and greater yield were primarily associated with greater deep root length and delayed root senescence, whereas in wheat, yield was most strongly correlated with total root length, and root system differences for stay-green were not as apparent. We speculate that the physiology of stay-green is different between these two species, and that barley may use a more efficient root system to withstand drought whereas wheat relies on a larger one. Several seedling traits related consistently to field root traits, but correlation directions were often opposite between barley and wheat. The connections between traits presented here could be useful for breeders seeking to improve crop adaptation to drought, but more genotypes and environments will need to be tested.
A “solid” solution for wheat stem sawfly (Hymenoptera: Cephidae) resistance: Genetics, breeding and development of solid stem wheat
(Wiley, 2023-06) Bathini, Akshara; Mendu, Lavanya; Pratap Singh, Nagendra; Cook, Jason; Weaver, David; Sherman, Jamie; Hager, Megan; Mondal, Suchismita; Mendu, Venugopal
Wheat (Triticum spp. L) production needs to be improved to meet the needs of a global population of >9 billion people by 2050. Increasing the productivity of the crop under conditions of abiotic and biotic stress to achieve food security continues to be a challenging proposition. Wheat stem sawfly (WSS) (Cephus cinctus Norton) has been considered as a serious pest of wheat since the late 19th century, causing devastating losses of wheat productivity in the Northern Great Plains of United States and regions of Canada. Developing resistant varieties of wheat that show consistent agronomic performances in varying environments is an effective strategy to manage WSS infestations. To achieve this goal, it is necessary to understand the underlying mechanisms of WSS infestation, damage, subsequent response of the host plant, and resulting yield losses. The review focuses on genetics, breeding, and development of solid stem (SS)-mediated WSS resistance in wheat since it has been the most effective method of genetic resistance in reducing wheat yield losses. Furthermore, the knowledge gaps that need to be addressed to develop an effective resistant cultivar against WSS are also discussed.