Thesis (Ph.D.) - Cairo University - Faculty of Agriculture - Department of Agronomy

The objectives were to explore the response and variation among some faba bean genotypes to variable soil drought-prone conditions. The elucidation of interrelationships among yield performances, stability parameters and drought tolerance/resistance are of great benefit for breeding to drought. Ten faba bean genotypes were evaluated under three watering regimes under field and pot experiments during 2013/2014 and 2014/2015 seasons. The ten faba bean genotypes were evaluated under normal (2100 m3/fad), medium (1680 m3/fad) and stress (1260m3/fed) irrigation regimes. However, the two pot experiments comprised the ten cultivars (in first) and five of them (in 2nd trial) using three moisture levels. When the plants were 30 days old, they were subjected to three moisture levels for 20 days. The levels were: 70% of the available water (as normal treatment), 45%, and 20% of the AW as medium (M) and stressed (S) treatments, respectively. The most important results could be summarized as follow: The tested faba bean genotypes could be classified into three categories to water use efficiency for SYR. The first group as low efficient for water use comprised N.1 which has b= 0.193. Only two varieties (G. 843 and C.5) may be considered as higher water use efficient. However, the remainder genotypes were considered an intermediate water use efficient group.Water stress progressively significantly reduced the growth, dry matter accumulation and RWC and the increase of the proline contents in the leaflets during the early stage of the faba bean. The tested faba bean genotypes possessed intrinsic variation of responses to water deficit during the early stage of growth. The genotypes M.1, M.3, C.4 and N.1 appeared to be the most sensitive ones, since their lower RWCs corresponded to high rates of reductions under stress conditions. Cultivar C.5 maintained significantly higher RWC and proline under stress and thus is less sensitive to drought. G.843 and C. 49 cultivars exhibited lower declines of RWCs due to AW reductions corresponded to higher RWC under moisture stress may be considered as tolerant to water stress

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