The effect of gw2 mutant alleles on grain weight and size in bread wheat

Montemayor Lara, Aura (2022) The effect of gw2 mutant alleles on grain weight and size in bread wheat. Doctoral thesis, University of East Anglia.

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Food production must increase to meet consumer demands in a population that is growing at a faster pace than current yield increases. Grain weight and size are amongst the most important agronomical traits as they impact grain yield. To date, our understanding on how grain weight is genetically controlled in wheat is still growing. The overall aim of this thesis was to understand if the GRAIN WIDTH 2 (GW2) mutant alleles play a role in increasing grain weight in different wheat genetic backgrounds tested under contrasting environments. To address this, a detailed characterisation of GW2 single, double and triple mutant near isogenic lines (NILs) was conducted in UK and international field trials. Likewise, we also aimed to understand whether these increases were mediated by the plant hormones gibberellins.

Thousand grain weight (TGW) and protein content increased consistently with increasing number of mutant GW2 copies in a dosage-dependent manner in cv Paragon under UK trials. Yield did not increase in the single and double mutants, but a significant decrease was found in the triple mutants. The effect of the gw2 alleles in two wheat cultivars, Reedling and Kingbird, grown across contrasting field environments (irrigation, heat stress and drought) was also assessed. Contrasting effects were found, with the gw2 allele having a positive effect on TGW and yield in Kingbird while in Reedling the effect was detrimental. Finally, two different glasshouse experiments were conducted to determine the effect of bioactive gibberellins and paclobutrazol applications on final seed weight and morphometrics. Our findings are relevant in the context of food security as they show the potential to increase grain size and grain protein content with a neutral effect on yield. Furthermore, we found that increases in yield are achievable during heat stress which is relevant in the context of climatic change.

Item Type: Thesis (Doctoral)
Faculty \ School: Faculty of Science > School of Biological Sciences
Depositing User: Chris White
Date Deposited: 23 May 2023 08:09
Last Modified: 23 May 2023 08:09


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