Evaluation of faba bean (Vicia faba L.) genotypes for drought tolerance under the subtropical region of New South Wales

Field and glasshouse experiments were carried out at the Plant Breeding Institute, Narrabri (PBI) to study the drought tolerance of faba bean, identify the quantitative trait loci (QTLs) for flowering time and assess the response to genotype by environment interaction. The result of the field study showed that the early season (ES) genotypes accumulated higher biomass, set more pods and had longer pod-fill duration, and produced higher grain yield than the late season (LS) genotypes. Four ES (11NF014b-1, IX474/4-12, PBA Nanu, and PBA Nasma) and two LS (PBA Samira and PBA Ranu) genotypes selected from the field study when evaluated under glasshouse conditions revealed that the ES genotypes had a conservative water use and stomatal conductance, and had 50 % reduction in transpiration at a higher fraction of transpirable soil water compared to the LS genotypes. Thus, it was concluded that the escape and avoidance mechanisms were the underpinning mechanisms of drought tolerance in faba bean. Based on the above results, the genetics of flowering time and related traits were studied in the Fiord/Doza#12034 derived recombinant inbred lines. The result showed that days to first flowering (DF), days to 50 % flowering (D50F), days to maturity (DM), and the node on which the first flower appeared (NFFA) were governed by 2, 2, 4, and 2 genes, respectively. Composite interval mapping identified two consistent QTLs for DF, D50F, NFFA and two minor QTLs for DM on five genomic regions. One pleiotropic QTL for DF and D50F linked to C231883-32.0 was mapped on chromosome 8 that could be used in marker-assisted selection program. Evaluation of faba bean breeding lines at Breeza and PBI for two years identified four genotypes (14NF612a-62, PBA Nanu, IX561/4-2-3 and 14NF618a-53) with high yield and moderate stability that can be used for improving yield in faba bean