Two field experiments were carried out on faba bean under a drip irrigation
system, during 1997/1998 and 1998/1999 seasons, to study the effect of three
watering levels {513.37 (11), 1026.74 (b) and 2053.48 (13) m³/fed.} on the growth and
yield of Giza 3 (V₁) and Giza 429 (V₂) varieties. A split plot design with three
replications was used, where irrigation levels occupied the main plots, meanwhile the . sub-plots were devoted to the two varieties. Water use efficiency W.U.E. was
calculated for ali the combination treatments. correlation and relative contribution of
some traits were calculated under each of the independent five treatments. The obtained results revealed significant increments in all traits except 100 seed
weight, were secured by varying watering level from h to b. Thereafter increments
were insignificant. Seed yield Ifed. in the two respective seasons, viz. 840.0 and
813.5 kg. were detected for 12. The V₁ out yielded V2 in both seasons. The
combination la x V₁ produced the highest seed yield, in both seasons, but without significant difference with 1₂xV₁. Water use efficiency (W.U.E.) was the highest in both
seasons for the 12xV1 treatment. Moreover the combination of either 12 or V₁ with others
produced the soundly W.U.E. With few exceptions, traits were positively correlated to each other, where all
correlation coefficient with seed yield I plant were significant. The 100 seed weight
always showed insignificant correlations. Frequency of correlation coefficient was
higher by increasing water supply and using V2. It seemed that plant height, no. of branches I plant and no. of pods I plant were the
main contributors to seed yield I fed. Their total contribution amounted to 62.49,
84.17, 73.70, 67.36 and 62.52% through the treatments of 11, 1₂, la, V₁ and V2,
respectively.