At European contact, Amerindian agriculture was based on a group of three major crops: maize, squash and beans. Two bean plants climbing on a living stake can be seen in the drawing of an indigenous American planting seeds with the aid of a digging stick, in the manuscript titled Histoire naturelle des Indes, known as the Drake Manuscript (dated about 1586). The illustration, titled ‘The manner and style of gardening and planting of the Indians’, also shows multieared maize, a cucur- bit vine bearing many large round fruits, capsicum pepper and a pineapple. Beans were sown in the same hole with maize, and the two crops complemented each other both as crops and as food. Maize acts as support of the climbing beans and is nitro- gen demanding, while beans are nitrogen fixing as a result of Rhizobium symbio- sis. Furthermore, maize and beans complement each other nutritionally, since maize seeds are deficient in the essential amino acid lysine; conversely, bean seed is defi- cient in the sulphur-containing amino acids (cysteine and methionine). The mixture of beans and tortillas (maize pancakes) provided a complete protein food that was the basis of Aztec and Mayan diets (Janick, 2011).
The knowledge of the ways through which the common bean was introduced in Europe is fragmentary, but it is likely that after the discovery of the Americas many introductions were made from many places. It is well known that the two common bean gene pools arrived in Europe at different times. If the Mesoamerican com- mon beans arrived in Europe just after the discovery of America, the Andean coun- terpart reached Spain in 1528, after the exploration of Peru. Common bean spread into Europe in a very short time, probably as a consequence of the high similarity of seeds with those of cowpea, V. unguiculata, a legume grown in Europe for millen- nia. Already in about 1508 the common bean was depicted in France in the prayer book of Anne de Bretagne, Queen of France and Duchess of Brittany (Figure 2.2). The image of a bean plant was identified by Jussieu (1772) as Phaseolus flore luteo and successively by Camus (1894) as the taxon entity P. vulgaris L. (Paris, Daunay, Pitrat, & Janick, 2006). The New World plant appears in the festoons of fruits, veg- etables and flowers including over 170 species of plants, which surround the gor- geous frescoes painted between 1515 and 1517 by Giovanni Martini da Udine at Villa Farnesina in Rome (Caneva, 1992).
The first description of common bean in European herbal references was done by Leonhard Fuchs, who reported in De historia stirpium (Fuchs, 1542) that the common bean had a climbing habit, white or red flowers, and red, white, yellow, skin-coloured or liver-coloured seeds with or without spots (Figure 2.3). However, it cannot be excluded that Fuchs reported a combination of traits belonging to both
P. vulgaris and P. coccineus. Subsequent descriptions were done by Roesslin in 1550, by Oellinger in 1553 and by Dodonaeus in 1554 (Zeven, 1997). A brief
selection of old manuscripts (1493–1774) mentioning P. vulgaris or its synonyms is reported by Krell and Hammer (2008).
The beginning of cultivation in Italy is supported by documents that fixed 1532 as the year in which the humanist and literate Pierio Valeriano received a bag of bean seeds as compensation for his work at the Pope Clemente VII court. The Pope had obtained the seeds from the Spanish Emperor Charles V, who ruled some Italian pos- sessions at that time. After sowing the common bean seeds in his fields located in Belluno province (northeastern Italy), Valeriano described the cultivation technique, the plant and seed morphology, and the supposed therapeutic properties of seeds in his poem ‘De Milacis Cultura’. During the fifteenth and sixteenth centuries, com- mon bean was introduced from Spain into Portugal, as a consequence of the flourish- ing commerce of this country with the Spanish region of Galicia (Rodiño, Santalla,
Figure 2.2 A common bean plant depicted in France in the prayer book of Anne de Bretagne, Queen of France and Duchess of Brittany (1508).
Montero, Casquero, & De Ron, 2001). Historical documents support the introduction of Phaseolus seeds from Italy and Spain to the present Hungary, part of the exchange of botanical species and scientific information among naturalists (Barona, 2007). Fine illustrations and botanical descriptions of Phaseolus plants are present in the
Stirpium per Pannonia, Austriam etc. (Clusius, 1583) under the names of Phaseolus
purkircherianus and Phaseolus africanus, tentatively identified as P. lunatus and
P. coccineus by K. Hammer (pers. commun.). In 1669 common bean was cultivated on a large scale in the Dutch province of Zeeland (Van der Groen, 1669), and after 20 years Valvasor (1689) reported the presence of the pulse in Slovenia. Over time, the dissemination across Europe surely occurred through seed exchanges among farmers being facilitated by territorial contiguity and similarity of environments.
In the early decades of the sixteenth century, the common beans introduced into Europe were surely subjected to selective pressures that gave rise to the loss of part of the germplasm carried from America. The driving forces of the genetic erosion that occurred in the early times were nature and farmers. Particularly, the ability to Figure 2.3 One of the early European images of common bean called Smilax hortensis from L. Fuchs’s herbal reference De historia stirpium (Fuchs, 1542).
survive in the new environments, the tolerance to long days and the resistance to pests and diseases represented important selecting factors. In addition, farmers took good care of their precious beans by sowing those having the most desirable fea- tures such as seed colour and size, resistance to biotic and abiotic stress, and good culinary quality. This process produced over the time a myriad of landraces well adapted to restricted areas of cultivation distributed in Europe. As a consequence, each country selected its own set of landraces able to fulfil the expectations of local populations. An example of morphological variation present in Italian common bean germplasm is shown in Figure 2.4. In the countries characterized by a high diver- sification of growing environments, the process of differentiation was more pro- nounced, so that each region had its own set of landraces. However, only in relatively recent times and for some European countries have detailed lists of the cultivated landraces been compiled. Authors of the eighteenth and nineteenth centuries men- tioned the great variation found in Spain (Moreno, Martinez, & Cubero, 1983), and
Puerta Romero (1961) classified the different cultivars used as traditional food by the Spanish on the basis of morpho-agronomic characters. A book describing 472 com- mon bean landraces cultivated in Italy was published by Comes (1910), while inves- tigations on the phenotypic variation within 1500 landraces grown in the Netherlands were performed by Nijdam (1947).
Starting from 1990s, systematic studies on the European common bean landraces have been carried out by recording morphological and agronomical traits, seed qual- ity traits and phaseolin pattern. This last biochemical marker allows the attribution of the landraces to one of the two major gene pools of the crop. The prevalence of the Andean types (76%) was first described by Gepts and Bliss (1988) and was confirmed by subsequent studies at national (Lioi, 1989; Logozzo et al., 2007; Ocampo, Martin, Sanchez-Yelamo, Ortiz, & Toro, 2005; Rodiño et al., 2001) and regional (Escribano, Santalla, Casquero, & De Ron, 1998; Limongelli, Laghetti, Perrino, & Piergiovanni, 1996; Lioi, Nuzzi, Campion, & Piergiovanni, 2012; Piergiovanni, Taranto, Losavio, & Pignone, 2006) levels. Within the European germplasm, the distribution of phaseo- lin types parallels that observed for American genotypes. Types C and T are clearly predominant within the Andean gene pool, while type S is prevalent within the Mesoamerican one. Evaluations carried out by using DNA-based markers have evi- denced a very high variation present within the Iberian germplasm. Based on these evidences, Santalla, Rodiño, and De Ron (2002) suggested Spain as a secondary diver- sification centre for the common bean.
It is well known that due to the environmental changes produced by human activi- ties over time populations of plant and animal species have become small, frag- mented and isolated. This trend also pertains to the common bean, but a detailed analysis of the studies published in the last decade evidences that, though the cul- tivation of common bean landraces is fragmented and confined to marginal areas, a significant number of landraces still survive on farm, mainly in the Iberian Peninsula (Moreno et al., 1983) and Italy (Piergiovanni & Lioi, 2010). This means that a sig- nificant fraction of the common bean variation present at the beginning of the twentieth century has been conserved up to present times. Generally, the perpetua- tion of landrace cultivation is not homogeneous within the countries. For example, Galicia appears to be the Spanish region still showing a wide common bean variation (Escribano et al., 1998). On the other hand, it is worthy to note that only 60% of the landraces grown in Catalonia (Spain) belong to the Andean gene pool, while in the rest of Spain 80% of landraces are of Andean origin (Rodrigo, 2000).
As concerns Italy, common bean landraces are still cultivated mainly in hilly areas along the Apennine ridge of the central and southern regions, such as Basilicata, Lazio and Abruzzo (Limongelli et al., 1996; Piergiovanni et al., 2006). Geographical isolation, as well as a lack of good roads until recent times, could explain the persistence of landraces in these areas. Unfortunately, it must be noticed that frequently landraces are mainly grown by elders for private use and only occasionally are sold in local markets. This, in addition to the diffusion of intensive agricultural systems based on commercial varieties, exposes the lan- draces to a high risk of loss in the coming years.