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University of Melbourne (2021)

Increasing lentil (Lens culinaris) adaptation to acute high temperature for arable cropping

Delahunty, Audrey Jane

Titre : Increasing lentil (Lens culinaris) adaptation to acute high temperature for arable cropping

Auteur : Delahunty, Audrey Jane

Université de soutenance : University of Melbourne

Grade : Doctor of Philosophy (PhD) 2021

Résumé partiel
Lentil (Lens culinaris Medik.) is an important crop for providing a source of dietary protein globally and is produced over three distinct agroecological zones ; Mediterranean, sub-tropical and temperate. Crop production is constrained by abiotic and biotic stresses, including acute high temperature (HT). For Mediterranean-type climates, such as southern Australia, low and unreliable winter rainfall (200 – 600 mm/year) and frequent acute HT events (heat waves) during the reproductive phase, limit production with yield losses up to 70%. Consequently, increasing the adaptation of commercial lentil varieties within contemporary breeding programs, by utilising global germplasm adapted to HT environments, is the critical next step.

This project screened 135 lentil genotypes (global landraces and commercial cultivars) for tolerance to acute HT occurring during the reproductive period. Screening was through a combination of late sowing (summer - chronic and acute HT), controlled-environment (acute HT) and subsequent in-season validation (winter - acute HT), where a daily maximum temperature of greater than 30 degrees Celsius was classified as HT tolerant. Genotypes selected for screening were predominately from regions where HT occurs during the reproductive period (i.e. Mediterranean and sub-tropical). Across HT treatments ranging from acute (3 days) to chronic HT during the reproductive period, we observed that HT caused a 48% reduction in grain yield across genotypes screened, which translated to an average reduction of 0.14 and 0.19% per degree (>30 degrees Celsius) for global landraces and commercial cultivars respectively. We identified 15 landraces and the commercial cultivar, Nipper to have a high level of yield stability under HT. Within the 15 landraces identified, AGG 73838 and 73154 consistently exhibited HT tolerance under the multiple screening strategies employed in this study. The additional 13 landraces were identified within the late sowing field screening process. The identification of these 15 HT tolerant landraces provides a valuable source of material that can be immediately utilised by Australian lentil breeding programs.

Mots clés : Lentil ; Pulses ; High temperature ; Genotype ; Screening ; Adaptation ; Mediterranean-type climate

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Page publiée le 3 novembre 2021