The yam bean (Pachyrhizus spp.) contains three closely related cultivated species: P. tuberosus (Lam.) Sprengel, P. erosus (L.) Urban, and P. ahipa (Wedd.). Its storage root dry matter content (SRDM) is usually low, although genotypes with a high SRDM have been identified (‘Chuin’ accessions). Flowers are often removed through flower pruning (FP) to increase storage root fresh matter yield (SRFY). The main objectives of this study were to investigate the potential for use in Benin (West Africa), to estimate the effect of FP, and to test whether roots could be processed into gari In total, 34 accessions were tested at one drought‐stress and one irrigated location. Means and genetic variance components were estimated for 33 agronomic traits. Without FP, the SRFYs of P. tuberosus, P. erosus, and P. ahipa were 13.9, 23.4, and 12.4 t ha−1, respectively, and the seed yields were 2.2, 5.2, and 2.1 t ha−1, respectively. The FP caused SRFY to increase by 48, 91, and 61% in P. tuberosus, P. erosus, and P. ahipa, respectively. The storage root dry matter yield (SRDY) of P. erosus was only slightly higher (∼8.5 t ha−1) than that of the Chuin accessions (∼8.0 t ha−1). Under drought, the SRDY was least affected in P. erosus Early‐maturing P. ahipa accessions were identified. All species could be used to make gari, which contained, on average, 5.5% protein, 58.5% starch, and 23.8% total dietary fiber. The crop has the potential for use in West Africa and has a large genetic variation for genetic improvement.

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Yam bean [Pachyrhizus DC.] is a legume genus of the subtribe Glycininae with three root crop species [P. erosus (L.) Urban, P. tuberosus (Lam.) Spreng., and P. ahipa (Wedd.) Parodi]. Two of the four cultivar groups found in P. tuberosus were studied: the roots of 'Ashipa' cultivars with low root dry matter (DM) content similar to P. erosus and P. ahipa are traditionally consumed raw as fruits, whereas 'Chuin' cultivars with high root DM content are cooked and consumed like manioc roots. Interspecific hybrids between yam bean species are generally completely fertile. This study examines the genetic diversity of the three crop species, their potentials for breeding and the identification of useful traits to differentiate among yam bean genotypes and accessions. In total, 34 entries (genotypes and accessions) were grown during 2000-2001 at two locations in Benin, West Africa, and 75 morphological and agronomical traits, encompassing 50 quantitative and 25 qualitative characters were measured. Diversity between entries was analyzed using principal component analysis, cluster analysis, multivariate analysis of variance and discriminant function analysis. Furthermore, phenotypic variation within and among species was investigated. Intraand interspecific phenotypic diversity was quantified using the Shannon-Weaver diversity index. A character discard was tested by variance component estimations and multiple regression analysis. Quantitative trait variation ranged from 0.81 (for total harvest index) to 49.35% (for no. of storage roots per plant). Interspecific phenotypic variation was higher than intraspecific for quantitative traits in contrast to qualitative characters. Phenotypic variation was higher in overall for quantitative than qualitative traits. In general, intraspecific phenotypic variation ranged from 0.00 to 82.61%, and from 0.00 to 80.03% for quantitative and qualitative traits, respectively. Interspecific phenotypic variation ranged from 0.00 to 95.02%, and 0.00-81.58% for the two trait types, respectively. The Shannon-Weaver diversity index (H′) was in general high and over 0.80 for most of the trait. Diversity within P. tuberosus was higher than within P. erosus and P. ahipa. Across the 50 quantitative and 25 qualitative traits, the ShannonWeaver diversity index of intra-and interspecific variation was around 0.83 and 0.51, respectively and was lower for qualitative than for quantitative traits. Monomorphism was observed in eight qualitative traits and one quantitative character. The first, second and third principal components explained, respectively, 39.1, 21.3 and 8.3% of the total variation in all traits. Pachyrhizus erosus, P. ahipa, and P. tuberosus ('Chuin' and 'Ashipa') were clearly separated from each other by these analyses. Multivariate analysis of variance indicates significant differences between Pachyrhizus species for all individual or grouped traits. Discriminant function analysis revealed that the first two discriminant functions were almost significant. Biases due to unbalanc...

Salinity is one of the major environmental constraints limiting agricultural productivity in the world. The effects of salt stress on growth, ions and organic solutes accumulation were investigated in two amaranth (Amaranthus cruentus) cultivars: Rouge (salt-resistant) and Locale (salt-sensitive). Young plants of these cultivars were exposed, in hydroponic system, to three concentrations of NaCl: 0, 30 and 90 mM. Growth parameters, ions, free proline and soluble sugars concentrations were determined after 2 weeks of stress. NaCl effect resulted in plant growth reduction in both cultivars but plants of cultivar Rouge were less affected compared to that of cv. Locale. Na + , proline How to cite this paper: Wouyou, A., Prodjinoto, H., Zanklan, A.S., Vanpee, B., resistance in these cultivars and that soluble sugars may play an important role in salt-resistance in Amaranthus cruentus. However, proline appears as a symptom of injury in stressed plants rather than an indicator of resistance.

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