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Experiments were made in glasshouses, growth cabinets and growth rooms to study the differential responses of the broad bean to water stress during the vegetative and flowering phases of growth. Plants in the flowering phase proved to be more sensitive to drought than in the vegetative period, and there were different responses (Relative Growth Rate) to temperature at different stages of plant growth. Day length and temperature influenced the position of the earliest flower initials on the stem, and intensity of flower shedding was aggravated by high temperature.

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A crop of broad beans was subjected to different water treatments with a view to finding the most economical irrigation policy. Increments in yield were obtained from the sixth to ninth irrigation, but the relative significance of each irrigation after the sixth was dependent upon whether irrigation water was saved during the vegetative and early flowering phase, or during the phase of pod development. The influence of the different water regimes on yield components and on some attributes of growth was studied.The broad bean, the most popular pulse crop in the Sudan, has received attention from Sudanese experimentalists in various fields with a view to establishing information that would lead to improved yields. For instance, El Saeed (1968) analysed the effects of plant populations and varietal characteristics on yield, and Kambal (1968) studied the agronomic characteristics of the most important varieties grown in the Sudan, with a view to establishing correlations between final yield and yield components, so that a single character could be chosen as an index of superiority for selection in the field. El Nadi (1969a) studied the differential effects of water stress, induced at different stages of plant development, on several attributes of growth which were directly or indirectly related to the final yield. This contribution, a continuation of the earlier work conducted in the United Kingdom, was designed to find the best irrigation policy to ensure economic returns. MATERIALS AND METHODSSixteen plots were used, 4 x 4 m. in a 1 • 5 feddan field (1 feddan = 1 • 038 acres) in the Demonstration Farm of the Faculty of Agriculture. The plots were adequately guarded by the bean crop, especially in the direction of the prevailing winds. Sowing was on ridges 70 cm. apart, at a spacing of 25 cm. along the ridge. Five seeds per hole were planted on 15 November 1967.The experimental plots were watered by a pump with a known rate of discharge, and water was applied to the plots by means of a movable pressure pipe at the rate of 75 mm. per irrigation. The number of irrigations in the different treatments is given in Table 1. The rest of the field was furrow irrigated at intervals of 14 days.Besides the experimental plots, beans were grown in two different models of lysimeters in order to assess potential evaporation rates over short periods. Three

V. faba plants were grown at 15 degrees or 25 degrees C in alternating wet and dry periods. Drying of the soil promoted deeper root growth. Total root weight was not affected. Shoots grew less with a dry treatment in both the vegetative and the flowering phase.-A.G.G.H. (Abstract retrieved from CAB Abstracts by CABI’s permission)