Faba Bean Genotypes Research Articles

Field evaluation of the resistance of some faba bean ( Vicia faba L.) genotypes to the parasitic weed Orobanche foetida Poiret

Heavy infestation of faba bean fields by Orobanche foetida is an emerging problem in Tunisia. Field trials during three consecutive crop seasons demonstrated the resistance of three genotypes to O. foetida, including the cv. Baraca, selected for resistance to O. crenata, and two Tunisian breeding lines, Bader and XBJ90.03-16-1-1-1. Resistant genotypes displayed a parasitism index two-fold lower than that of the susceptible checks. They carried 2–8 times less of tubercle attachments and 2–3 times less of emerged parasite spikes at pod setting stage and at crop maturity, respectively. Seed-yield losses by parasitism reached 90% for the susceptible checks and were two-fold lower for the resistant genotypes. Parasitism affected negatively the protein/starch ratio of seeds of both susceptible and resistant genotypes. The line XBJ90.03-16-1-1-1 was the best candidate for registration because of better productivity in non-infested fields and production of high-weight seeds.

Growth responses of cool-season grain legumes to transient waterlogging

Transient waterlogging reduces the yield of cool-season grain legumes in several parts of the world. The tolerance of grain legumes to waterlogging may vary between and within species. This study investigated the effects of 7 days of waterlogging and subsequent recovery (10 days) on plant growth to evaluate the variation in tolerance among 7 cool-season grain legume species, in sand culture in glasshouse experiments. Additionally waterlogging tolerance of 6 faba bean genotypes was also evaluated. Tolerance to waterlogging as indicated by root and shoot growth (as % of drained controls) was ranked as follows: faba bean > yellow lupin > grass pea > narrow-leafed lupin > chickpea > lentil > field pea. Faba bean produced adventitious roots and aerenchyma leading to increased root porosity (9% gas volume per unit root volume). Among the 6 faba bean genotypes screened, accession 794 showed the best waterlogging tolerance, but it was also the slowest growing accession, which might have contributed to apparent tolerance (i.e. growth as % drained control). It is concluded that waterlogging tolerance in grain legumes varied between and within species, with faba bean being the most tolerant. The variation in tolerance identified within the limited set of faba bean genotypes evaluated suggests scope for further genetic improvement of tolerance in this species.

Effects of Phenylpropanoid and Energetic Metabolism Inhibition on Faba Bean Resistance Mechanisms to Rust

ABSTRACT Effects on penetration and hypersensitive resistance of the cinnamyl acid dehydrogenase (CAD) suicide inhibitor ([(2-hydroxyphenyl) amino] sulphinyl) acetic acid, 1.1 dimethyl ester, which suppresses phenylpro-panoid biosynthesis, and of D-mannose, which sequesters phosphate and reduces energy available in host cells, were studied in faba bean (Vicia faba) genotypes with differing resistance mechanisms to faba bean rust (Uromyces viciae-fabae). Inhibition of CAD reduced penetration resistance in lines 2N-34, 2N-52, V-1271, and V-1272, revealing an important role for phenylpropanoid biosynthesis in the resistance of these lines. Inhibition of CAD also inhibited hypersensitive cell death in these lines. D-mannose had little or no effect on resistance. By contrast, CAD inhibition did not affect penetration resistance of line BPL-261, which has a high degree of penetration resistance not associated with hypersensitive cell death. In BPL-261, D-mannose inhibited penetration resistance. The parallelism between the faba bean genotype responses to rust observed here and the response of barley genotypes with differing resistance mechanisms to powdery mildew after similar inhibitor treatments is analyzed and discussed.

Effets de la température et de la dose de l'inoculum sur les composantes de la résistance partielle de la fève au Botrytis fabae Sard.

Five faba bean genotypes partially resistant and susceptible to Botrytis fabae were used at the laboratory to follow the effect of the temperature and the concentration of the inoculum on the expression of four components of partial resistance. The incubation period was longer at 5 °C and appeared significantly shorter from 10 °C to 25 °C but did not allow a good discrimination between the genotypes. The area under disease progress curve (AUDPC) of the lesion size increased from 5 to 25 °C with significant differences between the genotypes especially starting from 15 °C. The latent period decreased and spore production increased from 10 °C to 20 °C but were expressed only at 20 °C and 25 °C. The size of the lesions and the number of spores increased and the latent period decreased with increasing the inoculum concentration. The inoculation by 2.105 and 2.106 spores/ml gave a better expression of resistance. With 2.104 spores/ml, the two components latent period and spore production were not expressed on the resistant genotype BPL710.

Development of SCAR markers linked to a gene controlling absence of tannins in faba bean

Faba beans are inexpensive, nutrient-dense sources of plant protein, but anti-nutritional factors such as condensed tannins reduce the biological value of their protein. Two recessive genes, zt-1 and zt-2, control the absence of tannins in faba bean seeds and also determine a white flower character on the plant. However, crosses between them produce coloured F1 plants with tannins that contaminate the crop. Therefore, it is important to identify the gene present in all tannin-free cultivars and gene bank accessions to enable breeders to choose appropriate genitors for their crosses. The aim of this study was the identification of markers linked to zt-1, one of the genes governing free tannin content in faba bean. A segregating F2 population derived from the cross between the coloured flower and high tannin content genotype Vf6 and a zt-1 line was developed and characterized phenotypically. Bulked Segregant Analysis (BSA) was used to identify Random Amplified Polymorphic DNA (RAPD) markers linked to the zt-1 gene. Four RAPD loci (OPC5551, OPG15600, OPG111171 and OPAF20776) showed polymorphism between the contrasting bulks. The markers were sequenced to develop specific Sequence Characterised Amplified Regions (SCARs). Amplification of SCC5551 produced a single product which was only observed in the white flowered and zero tannin content genotypes, whereas SCAR SCG111171only produced a band in F2 plants with coloured flower and high tannin content. SCARs SCC5551 and SCG111171 were tested for their applicability for routine screening in 37 faba bean genotypes differing in flower colour and tannin content. SCC5551, allowed the prediction of the zt-1 genotypes with a 95% of accuracy, underscoring the potential of this SCAR marker as a cost-effective tool for MAS in large faba bean breeding populations.

Bazı Yöresel Bakla (Vicia faba L.) Populasyonlarının Bitkisel Özellikleri ve Tane Verimlerinin Belirlenmesi

This study was conducted in order to determine plant characteristics and seed yields of some local faba bean (Vicia faba L.) populations in comparison with registered faba bean cultivars/lines between 2003 and 2005 in Samsun. Totally 15 genotypes, three faba bean cultivars (Eresen-87, Filiz-99 and Lara), two lines (FLIP85-172FB and FLIP86-116FB) from ICARDA, 10 local populations collected from some districts and villages of Samsun, Amasya, Sinop and Tokat provinces, were used in the study. Seed yield ranged from 1654.3 to 3914.8 kg/ha and from 2779.9 to 5892.3 kg/ha in 2003-2004 and 2004-2005 growth season, respectively. On average of two years, the highest and the lowest seed yields were obtained from Eresen-87 (4790.2 kg/ha) and G14 population (2217.1 kg/ha), respectively. G3, G4, G5, G6 ve G7 populations were among the first ten high yielding genotypes, which were not statistically different from each other. G3 was in the second rank for seed yield (3950.9 kg/ha) among all faba bean genotypes. Although plants produced more vegetative parts in the first year, biological yieds were lower in the first year than in the second year. High seed yields had an important role in high biological yields determinated in the second year. The highest harvest index was determined in Eresen-87 (57.73%), which was also superior for seed yield.

N2fixation in faba bean grown under saline and non-saline conditions using a 15N-tracer technique

A pot experiment was conducted to study the performance of faba bean and barley growing under saline conditions, in terms of dry matter yield, total N, and percentages and amount of N derived from the soil, fertilizer and atmosphere using a 15N isotope dilution method. Three saline treatments were employed: 1) plants were grown on saline soil and irrigated with saline water (SsWs); 2) plants were grown on saline soil and irrigated with non-saline water (SsWn); and 3) plants were grown on non-saline soil and irrigated with saline water (SnWs). Furthermore, a control treatment was employed by growing the plants on non-saline soil and irrigating them with non-saline water (SnWn). The different salinity treatments reduced plant growth and the reduction was more pronounced in faba bean than in barley. However, the relative growth reduction of plants grown only on saline soil, using non-saline water, did not exceed 50% of the control, whereas the reduction exceeded 50% when plants were grown under completely saline conditions. The percentage of N2fixed (%Ndfa) was not affected negatively by saline conditions.the results clearly demonstrated that the effect of salinity on faba bean was more evident on plant growth than on N2-fixing activity. Further studies are needed to obtain more salt-tolerant faba bean genotypes that possess a higher growth rate. This could simultaneously improve yield and N2fixation under severely saline conditions.

Root nodulation and nitrogen accumulation and partitioning in legume crops as affected by soil solarization

Soil solarization is a preplanting technique used in hot climates to control weeds and soilborne pathogens consisting of mulching the soil surface with polyethylene sheets. The increase in temperature associated with solarized soil could affect nitrogen availability for grain legume crops through effects on nitrogen fixing soil microorganisms or other mechanisms. To examine the effects of solarization on natural root nodulation and nitrogen accumulation and partitioning in the plant, two solarization field experiments were carried out over two planting seasons, involving genotypes of both faba bean (Vicia faba) and chickpea (Cicer arietinum). The effect of sowing date was also studied in the first season. Solarization increased the maximum soil temperature by 9–10 °C in the first, and by 13–15 °C in the second season. At 5 cm below the solarized soil surface, a temperature of over 46 °C prevailed for 146 and 280 h over the two respective seasons, while this temperature was not attained in unmulched soil. Solarization delayed the initiation of nodulation and consistently reduced the nodule number per host plant, but generated an approximate doubling of mean nodule weight. The total nodule mass per plant was not affected by the treatment in the first season, but was reduced in the second season. Solarization significantly increased the concentrations of NO3− -N, Na+, Zn2+, Ca2+ and K+ in the soil extract, and the total nitrogen accumulated in the whole plant. This latter increase was due to both higher plant growth and a greater plant nitrogen concentration. The increased nitrogen level in the plant was not uniform with respect to plant component, varying from 57% in the roots to 198% in the pods and seeds. The plants grown in non-solarized soil accumulated about 31% of their total N content in the shoots of the parasitic weed Orobanche crenata. Solarization dramatically improved grain yield by 300–900% in both seasons and in all genotypes studied, due to increased N availability in soil, N accumulation in plants, improved plant growth, and complete control of the parasite weed O. crenata. On the basis of these beneficial effects, soil solarization, which avoids site contamination and is suited to organic farming, should be a good opportunity in Mediterranean areas where the level and stability of grain yields are low, and the infestation of O. crenata is high.

Yield and Yield Components of Faba Bean Genotypes Under Rainfed and Irrigation Conditions

Yield and Yield Components of Faba Bean Genotypes Under Rainfed and Irrigation Conditions

Estimates of broad-sense heritability for seed yield and yield criteria in faba bean (Vicia faba L.).

Eight faba bean (Vicia faba L.) genotypes were grown at lowlands of the west-Mediterranean region of Turkey in order to estimate the broad-sense heritability for plant height, number of stems and pods per plant, seed yield, biological yield, 100-seed weight, days to flowering and maturity. The heritability for plant height, number of stems and pods per plant, seed yield, biological yield, 100-seed weight, days to flowering and maturity were estimated as 83%, 63%, 43%, 62%, 52%, 99%, 97% and 97%, respectively. It was found that seed weight was the least affected trait across changing environmental conditions and followed by days to flowering and maturity. On the other hand, number of pods per plant, biological and seed yields and number of stems per plant were the most affected traits versus environmental conditions.

Evaluation of a collection of faba bean ( Vicia faba L.) genotypes originating from the Maghreb for resistance to chocolate spot ( Botrytis fabae) by assessment in the field and laboratory

Screening of 136 faba bean lines forresistance to chocolate spot caused by thefungus Botrytis fabae was conductedin field conditions with artificialinoculation. Detached leaves of thesegenotypes were also assessed for diseaseseverity after inoculation under controlledconditions with a B. fabaesuspension. The BPL710 and Aguadulcegenotypes were inserted as resistant andsusceptible checks, respectively. Diseasesymptoms were scored visually in bothexperiments. Diameter of lesions andproduction of spores were measured in thedetached leaf assay. The disease scoreindex and diameter of lesions were used tocalculate the area under the diseaseprogress curve (AUDPC) to measure thedisease progress. Significant differenceswere detected among genotypes for reactionto the disease in the field. However, nocomplete resistance was observed. Forhighly susceptible and highly resistantgenotypes, the laboratory assay generallyled to the same result as the field test,nevertheless, for more intermediate levelsthe agreement was weak. On detached leaves,diameter of lesions was significantlycorrelated to the AUDPC of disease scores(r = 0.89) and moderately correlated tosporulation (r = 0.52). The correlationbetween field AUDPC and detached leaf AUDPCof disease scores was low (r = 0.26). A lowcorrelation was also observed between fieldAUDPC and lesion size (r = 0.30) andbetween field AUDPC and sporulation (r =0.32). Among the 136 genotypes evaluated inthis study, nine were convincingly andhighly resistant in both tests. FRYM167 andFRYA58 genotypes were the most resistantwith low AUDPC of disease scores, low AUDPCof lesion diameter and low sporeproduction. These genotypes obviously havepartial resistance.

Analysis by detached leaf assay of components of partial resistance of faba bean (Vicia faba L.) to chocolate spot caused by Botrytis fabae Sard

Five faba bean (Vicia faba L.) genotypes with different levels of field susceptibility to chocolate spot caused by Botrytis fabae, were analysed for the components of partial resistance in a laboratory assay on living detached leaves. The incubation period (IP), the number of spots (NP), the lesion diameter (LD), the latency period (LP) and the number of spores/leaflet (NS), were determined and statistically analysed. Parameters LD, LP and NS were involved in characterising partial resistance, but IP did not appear to play a role. NS did not become a significant factor until 20 h after inoculation. Genotype FRY167 was most resistant with the lowest LD and NS values and the longest LP. In contrast, FRY30 had the highest level of susceptibility, with the highest LD and NS and the shortest LP. However, the resistant control BPL710 showed a slight deviation in that it expressed a long LP which was not significantly different from the values of the susceptible control Aguadulce. The absence of a correlation between LP and NS in BPL710 opens a discussion on the genetic control of its resistance.

Differentiation Among Bean Leafroll Virus Susceptible and Resistant Lentil and Faba Bean Genotypes on the Basis of Virus Movement and Multiplication

AbstractSystemic movement of Bean leafroll virus (BLRV) in susceptible and resistant lentil and faba bean genotypes was studied using plants grown in a plastic house. All the plants studied were inoculated with BLRV by viruliferous pea aphids (Acyrthosiphon pisum). Five plants/genotype of lentil and faba bean were harvested, respectively, at 3, 6, 9, 12 and 18 days and 1, 2, 3, 4 and 5 weeks after inoculation. Each plant was split into growing point, stem, stem base and root, and each was tested using tissue blot immunoassays (TBIA). Virus concentration in each section was estimated using a 0–3 score and a relative TBIA value was estimated accordingly for each genotype. In susceptible lentil genotypes (ILL 8063 and ILL 2581), BLRV was present in low concentrations in the growing point 3 days after inoculation and in high concentrations in all parts of the plant after 6 days. By contrast, the virus was not detected in the highly resistant genotype (ILL 74) until 18 days after inoculation. In the faba bean genotypes studied, BLRV was detected in high concentrations in all parts of the highly susceptible genotype (Fiord) 1 week after inoculation but only after 3 weeks in resistant genotypes (e.g. BPL 5274), but was not detected in the highly resistant genotypes (BPL 5278 and BPL 5279) 5 weeks after inoculation. The replication and systemic movement of BLRV was thus slower in resistant genotypes than in susceptible genotypes. Moreover, the use of TBIA scores clearly and easily differentiated resistant and susceptible genotypes. Our results suggest that BLRV movement and multiplication can be useful criteria when differentiating resistant from susceptible genotypes. In addition, undertaking the preliminary screening in a plastic house requires less space than direct planting in the field.

Evaluation of the SPAD Value in Faba Bean (Vicia fabaL.) Leaves in Relation to Different Fertilizer Applications

The correlations of the reading of a portable chlorophyll meter (SPAD-502) with the chlorophyll and N contents of leaves of two faba bean (Vicia fabaL.) cultivars, Japanese (Ryousai-issun) and Egyptian (Cairo 241), were examined. The SPAD readings positively correlated (ρ<0.01) with the chlorophyll contents and the r2 values were 0.99 and 1.00 for Ryousai-issun and Cairo 241, respectively. A close linear relationship (ρ0.001) was observed between SPAD reading and total leaf N content at the pod development stage of faba bean plants with r2 = 0.88 and 0.99 for Ryousai-issun and Cairo 241, respectively. The SPAD reading was the highest in the 2nd to 4th leaves counted from the top (the youngest fully expanded leaves). The changes in leaf chlorophyll content of both cultivars from 3 weeks after transplanting to the ripening stage showed an incomplete “M” type curve. SPAD readings were significant¬ly higher in Ryousai-issun than in Cairo 241 throughout the growth season. Organic fertilizers application improved faba bean plant growth. These results suggest that the SPAD-502 chlorophyll meter can be used to measure chlorophyll and nitrogen contents of faba bean leaves for quick screening faba bean genotypes.

New faba bean genotypes resistant to chocolate spot caused by "Botrytis fabae"

The response of sixty-seven genotypes of faba bean (Vicia faba) to the virulent isolate IBf24 of Botrytis fabae was studied under field conditions. Five of these genotypes (LPF39, LPF113, LPF44, LPF237 and LPF05) were moderately resistant to chocolate spot according to their MDI (mass disease index). Ten lines (LPF38, LPF41, LPF64, LPF95, LPF106, LPF132, LPF225, LPF228, LPF23, LPF233) were moderately susceptible, and fifteen lines (LPF54, LPF61, LPF66, LPF89, LPF124, LPF129, LPF131, LPF134, LPF138, LPF152, LPF173, LPF174, LPF190, LPF274, BPL710) susceptible as shown by their MDI values but with low AUDPC (area under disease progress curve) values and were believed to have an overall tolerance to the disease. Fourteen of the genotypes tested in the field, as well as the resistant BPL710 and the susceptible Rebaya 40 controls, were further screened under greenhouse conditions in order to confirm the field evaluation. In both the field and the greenhouse trials, the four lines LPF44, LPF237, LPF05 and LPF113 showed the highest level of resistance to the disease. These trials also revealed that genotypes with only overall tolerance may yet constitute interesting sources of resistance. Genotype BPL710, with known resistance to B. fabae races in the Mediterranean region, was found to be susceptible in the field but moderately susceptible in the greenhouse, suggesting the appearance of new races of this pathogen.

First Record in Syria of Didymella fabae, the Teleomorph of Ascochyta fabae and Causal Organism of Faba Bean Blight.

Ascochyta blight, caused by Ascochyta fabae Speg., is a common and destructive disease of faba bean (Vicia faba L.) in the Middle East, Europe, Canada, New Zealand (4), and Australia. The main sources of inoculum are debris and seeds from which spores are air- and splashborne. The teleomorph of A. fabae has been reported previously only from England (2). The presence of the teleomorph supports the variability reported in the fungus populations from Canada (3) and Poland (1). Stems of faba bean plants, severely infected with A. fabae, were collected in July 1999 from Tel Hadya, Syria. The plants previously had been inoculated with a mixture of isolates of the pathogen, collected from the main faba bean-growing regions in Syria between 1996 and 1998, and kept under shade. The infested stems were used to inoculate the ICARDA Faba Bean Ascochyta Nursery planted on 29 November 1999. During late January 2000, symptoms appeared on the susceptible faba bean genotype. Stem pieces from debris used for inoculations were collected from the field and examined microscopically for the presence of ascomata. The maximum, minimum, and mean temperatures and rainfall at Tel Hadya during December 1999 were 16.5, 5.8, and 8.7°C and 22.4 mm, respectively. There were 16 nights when temperatures dropped below 0°C, and 10 nights when temperatures were between 0 and 5°C. Ascomata of A. fabae ranged from 76 to 209 μm wide (average 158 ± 3.9 μm) and 101 to 285 μm in length (average 178 ± 4.1 μm). Asci were 10 to 15 μm wide (average 14 ± 0.3 μm) and 51 to 96 μm long (average 63 ± 1.1 μm). Ascospores were 5 to 8 μm wide (average 7 ± 0.2 μm) and 15 to 20 μm in length (average 17 ± 0.3 μm). These measurements are comparable to those reported from England. Individual ascomata were dissected from stem tissue and fixed to the lids of petri dishes containing 2% water agar. After 24 h, the petri dishes were examined microscopically to locate ascospores on the surface of the medium. Germinating ascospores and developing colonies were transferred from water agar to faba bean dextrose agar. Colonies characteristic of A. fabae developed on the latter medium within 7 days of incubation at 20 ± 2°C. Pathogenicity tests of developing colonies were carried out on 3-week-old faba bean plants (Giza 4) using a spore suspension (2.5 × 105 spores per ml) of each of the isolates. Both inoculated seedlings and control seedlings inoculated with sterile water were covered with plastic bags for 48 h in a plastic house maintained at 18 ± 2°C. After removal of the plastic bags, seedlings were wetted four times per day by spraying with tap water to runoff. Inoculated plants showed characteristic symptoms of Ascochyta blight 15 days after inoculation. The fungus was reisolated from lesions that developed on leaflets of all inoculated seedlings, but not from any of the control seedlings. This is the first report of the occurrence of A. fabae, the sexual stage of Didymella fabae Jellis & Punithalingam in Syria, and indicates that the fungus could develop population variants. These findings have implications for breeding for resistance to Ascochyta blight.

060 Differential Responses of Egyptian Faba Bean Genotypes to in Vitro Callus Induction

Callus induction in 12 genotypes of faba bean (Vicia faba L.) genotypes from Egypt were examined. Cotyledon, leaf petiole, and stem explants were cultured on two basal agar media; Murashige and Skoog (MS) and Gamborg (B5). The media contained 0.5 mm 2,4-D, 0.25 mm NAA, and 30 g of sucrose/L. Calli were easily formed in B5 media and induction rate was significantly dependent on the genotype. The highest induction rates occurred mostly in genotypes from Assiut Univ., Egypt, and in a local variety `Goya'. These callus cultures will be used for in vitro screening of the faba bean genotypes for tolerance to salt and drought, respectively.

Genotypic variation for drought tolerance in Vicia faba

AbstractInstability of yield in faba bean is partly caused by drought susceptibility. Four sets with 10‐19 faba bean genotypes each were evaluated in multilocal field trials between 1992 and 1996. Stress occurred as natural drought in one experiment and as artificial terminal drought in three experiments. Artificial drought was induced by rain shelters; the control treatment was irrigated. Tolerance was assessed as the ratio of yield under drought (Yd) to well‐watered yield (Yw). Highly significant variances between genotypes occurred; heritability of tolerance was 0.51 &lt; h2 &lt;0.88. Exotic (North African. Latin American) genotypes were more tolerant than adapted material. Correlations between Yw and Yd were 0.77** &lt; r &lt;0.97**, and variance of Yd was less than one‐third of the variance of Yw. Drought tolerance was negatively correlated with Yd (‐0.41 &lt; r &lt; ‐0.22). Relative reduction of plant height due to drought was a promising trait to improve drought tolerance indirectly in two sets. The prospects of improving Yd are good: heritability was 0.68 &lt; h2 &lt; 0.86. Genetic improvement of drought tolerance also seems feasible. A specific cross was proposed to create improved material.

Assessment of Drought Resistance of Crop Genotypes by Means of the Water Potential Index

ABSTRACTThe evaluation of crop genotypes for their adaptability is often performed by means of regression techniques of yields against some kind of an environmental index as independent variable. The weakness of these techniques lies in the lack of a direct assessment of a given environment by specific environmental factors. In this work, a new index, the water potential index (WPI), is suggested as a measure of the total water stress experienced by any crop in a given environment for a specific time interval. The index is derived from the integral of the course of leaf water potential over time. Its usefulness is demonstrated in evaluations of field‐grown bread wheat [Triticum aestivum (L.) em. Thell] and faba bean (Vicia faba L.) genotypes of contrasting characteristics by yield vs. WPI linear regression analysis. In these regressions, the intercept represents the “potential” yield at no stress conditions and the slope represents the “adaptability” of each genotype. It was found that the dwarf wheat cultivars Yecora and Siette Cerros exhibited higher potential yields and lower adaptability in comparison with the tall cultivar Generoso. In faba beans, the smaller the seed size of a cultivar, the lower was the potential yield and the better the adaptability. On the basis of this regression analysis, different response scenarios of hypothetical crop genotypes are described. Furthermore, the “relative adaptability” concept is presented, in which the potential yield effect is removed from the adaptability of any genotype. Examples of the use of WPI for obtaining information on the involvement of water shortage in specific growth stages of the wheat crop or for assessing the sensitivity of faba bean yield components to water shortage are presented.

Genetic variability for feeding value of faba bean seeds (Vicia faba): Comparative chemical composition of isogenics involving zero-tannin and zero-vicine genes

In a preliminary experiment, 74 faba bean genotypes including winter genotypes (autumn-sown) and spring genotypes (spring-sown) and isogenic population pairs (tannin-containing v. tannin-free and vicine/convicine-high v. vicine/convicine-low), were analysed for the chemical composition of their seeds. A large variability was found for the main constituents (starch, protein and fibre). Autumn-sown genotypes contained 2·3% less proteins but 2·5% more starch in the seed dry matter (DM) than spring-sown genotypes. The vc− gene, which lowers the vicine and convicine contents, did not significantly modify the main seed components in the isogenic comparisons. The zt1 and zt2 genes, which eliminate condensed tannins in the seed coats, lowered by 2·1% the proportion of the seed coat in the DM. In the isogenic comparisons, the zt2 gene had a stronger effect than zt1 in reducing the total seed fibre and increasing the protein content.In a second experiment, from the original 74 genotypes, 12 contrasted genotypes were selected and multiplied for animal nutrition trials. Their chemical analysis confirmed the variability between the faba bean categories observed in Expt 1, but detailed chemical analyses illustrated the variability in amino acid, fatty acid, amylose and oligosaccharide composition, trypsin inhibitory activity, condensed tannins, lectins and phytic phosphorus contents.