Response of three faba bean varieties to number of irrigations on physiological traits, yield and yield components, and water productivity under calcareous soil conditions

الملخص EN

A field experiment was conducted at the experimental farm of Nubaria Agricultural Research Station, Agricultural Research Centre, Ministry of Agriculture and Land Reclamation, El-Behiera Governorate, Egypt, during the two successive winter seasons of 2017/2018 and 2018/2019 to study the effect of three irrigation treatments (I1: three, I2: two, and I3: one irrigation after sowing irrigation) on the physiological response, productivity, amounts of applied irrigation water, water consumption, and productivity of irrigation waterof three faba bean varieties (Nubaria 3, Nubaria 1, and Giza 716).

Results could be summarized as follows: - Deficit irrigation treatment (I3) significantly decreased leaves chlorophyll content, seed protein content, plant height (cm), number of branches/plant, number of pods/plant, number of seeds/plant, seed yield/plant, seed yield, relative water content (RWC), and transpiration rate (TR) in both seasons.

While, proline content, total soluble carbohydrate of leaves and stomatal resistance were significantly increased.

- Increasing irrigation water led to decrease in water use efficiency values.

Maximum productivity of irrigation water (PIW) values were obtained from applying I3 irrigation treatment with Giza 716 variety.

- Regarding the effect of varieties, Nubaria 3 recorded the highest values of protein percentage (%), total soluble carbohydrates, chlorophyll content, and RWC.

However, the highest values for proline content, number of seeds/plant and seed yield (ardab/fed) were recorded from Nubaria 3 and Giza 716 varieties.

The maximum values of stomatal resistance (SR) were recorded for Nubaria 3 followed by Giza 716, and Nubaria 1.

An opposite trend was observed for transpiration rate (TR).

- The interaction effects between irrigation treatments and varieties were found to be significant in all tested traits.

Maximum values of protein of seeds content, plant height, no of pods/plant, no of seed/plant, and RWC were obtained when Nubaria 3 and Giza 716 varieties irrigated with three irrigations after sowing irrigation (I1).

Nubaria 1 recorded the highest number of branches/plant under such treatment.

The highest accumulation of total soluble carbohydrates and proline contents in leaves, the highest values of stomatal resistance and lowest transpiration rate recorded in Nubaria 1 variety under the dry treatment (I3).

- In the light of the present study, the maximum faba bean yield and its components were obtained from Nubaria 3 and Giza 716 irrigated by treatment I1 (three irrigations after sowing irrigation) followed by medium treatment I2 (two irrigations after sowing irrigation) with insignificant difference.

On the other hand, the maximum values of Productivity of irrigation water (PIW) were obtained from Giza 716 followed by Nubaria 3 under I2 (two irrigations after sowing irrigation) compared to Nubaria 1.

However, sowing Nubaria 3 and Giza 716 varieties irrigated with two irrigations after sowing irrigation is recommended under calcareous soil conditions and surface irrigation system, while if irrigation water is the limiting factor for faba bean production, or if the farmer is facing water scarcity, we recommend sowing Nubaria 3 variety with only one irrigation, which gave an average seed yield 7.82 (ard/fad) (2.88 ton/hectare) for the two years, and saved about 412 m3 of irrigation water compared to three irrigations after sowing irrigation