2.8. Color, shape, number, and size of seeds as well as seed maturity

landraces result to higher variation within the population [10]. Landraces are also much

The higher germination percentage of seed depends on the availability of environmental factors, like adequate temperature, light, salinity, moisture, and water [30]. The germination stage is the most important stage in the crop survival, which is to determine the amount of water and nutrient resources that need to be applied [31]. In Mexico the germination percentage ranges from 58.27 to 73.51% among the P. vulgaris landraces [31]. P. vulgaris landraces from Uganda show uniformity in seed germination, where after 5 days of planting all genotypes

P. vulgaris differed in their growth habits which may be climbing or semiclimbing, erect or even bush type [1]. Their growth habit can either be determinate or indeterminate [17]. These growth habits are classified into four major classes, namely, Type 1 has determinate, upright, and bushy habit; Type 2 has indeterminate, upright, and bushy habit; Type 3 has indeterminate, prostrate with no climbing or semiclimbing, habit; and Type 4 has indeterminate and

The plant height of Brazilian P. vulgaris landraces ranges from 338 to 988 mm [27]. According to Stoilova et al. [32], plant height of landraces from Portugal and Bulgaria ranges from 195 to 1234 mm with the average of 447 mm. However, Sozen et al. [33] record plant height among Turkey landraces ranging from 200 and 3100 mm. The plant height shows wide variability among the landraces in Madeira where climbing landraces have a variation from 1086 to

P. vulgaris landraces from Portugal and Bulgaria with climbing growth form have the numerous branches than bushy type [10]. The number of shoots in the main stem shows variation, with a range either from 4 to 14 among the landraces in Uganda [11] or from 17 to 57 in Nigeria [1]. The number of leaves per plant varies with a range from 45 to 96 leaves among P. acutifolius

Days to flowering also vary among P. vulgaris landraces, which generally commences from 26 to 51 days after planting in Portugal and Bulgaria landraces [10], Honduras [35], and Uganda [11]. However, a variation in days to flowering from 35 to 75 days after sowing is evident among landraces from Mexico [32]. The color of the flowers among P. vulgaris landraces can be white, carmine, red, purple, pink, white with lilac edges, or white with red stripes [11, 32].

The color of immature pods in Uganda P. vulgaris landraces is pure green; green with purple, carmine, or red stripes; dark purple; carmine, red, or pink, whereas physiologically matured

appreciated for their taste, high nutritional value, and short cooking time [28].

2.5. Growth form, plant height, and number of branches and leaves

2.4. Germination percentage

64 Rediscovery of Landraces as a Resource for the Future

emerge from the soil [11].

strong climbing habit [17].

landraces in Botswana [34].

1441 mm and bushy from 138 to 382 mm [5].

2.6. Days to first flower formation and flower color

2.7. Color, shape, number, and size of pods

Genetic variability in P. vulgaris landraces is sometimes indicated by seed color, size, and shape (Figure 1) [28, 38]. Shininess of seeds can either be shiny, intermediate, or opaque [39]. There is a wide variation in both seed coat main and secondary colors. Seed coat main color can be brown, cream, red, white, or yellow, while the secondary color can be black, red, or violet on the entire grain [28, 40]. White grain seed is commonly used by commercial farmers [41]. Seed shape can be round (circular), oval, kidney, hook, truncate, as well as cuboid (rectangular) shape [12, 40].

The number of seeds per pod among the P. vulgaris landraces has comparable ranges from 4.96 to 5.01 in Greece [37], from 2.8 to 6.6 in Italy [13], and from 3.60 to 5.53 in Zimbabwe [42]. Landraces from Italy that are categorized into traditional and nontraditional agro-food products vary from 3.2 to 6.3 and from 3.0 to 4.9 seeds per pod, respectively [43].

Seed size varies widely among P. vulgaris landraces. In Kosovo, seed length has a range of 12.8–18.3 mm, width 7.4–10.1 mm, and thickness 4.6–6.9 mm [44]. In Turkey, seed length has a variation of 11.8–23.1 mm, width 5.8–15.4 mm, and thickness 0.7–10.0 mm [38]. Seed length also ranges from 10.0 to 16.7 mm, from width 6.1 cm to 9.8 mm, and thickness from 4.2 to 8.2 mm, in Iran [14]. Consumers normally favor medium-sized to large-sized seeds probably because of their mass, taste, and easiness in hydration when cooked [45]. Seeds have certain properties such as early or late maturity, as some physiological maturity ranges from 65 to 120 days [10, 46].

#### 2.9. Plant resistance to diseases and pests

In Tanzania, the screening of different P. vulgaris landraces and released varieties against Phaeoisariopsis griseola (Sacc) [Ferr], which causes angular leaf spot disease, shows that landraces were resistant, while varieties were either intermediate resistant or susceptible to this disease [20]. This suggests the presence of resistant genes on these landraces toward the P. griseola. The response of P. vulgaris parental lines to infestation by bean fly (Ophiomyia phaseoli) ranges from susceptible to resistant in Kenya [47].

3. Conclusion

Author details

Nontuthuko R. Ntuli

References

Natal; 2013

Evolution. 2011;58:861-874

seed quality. Diversity. 2010;2:837-862

sition and Analysis. 2012;26:72-80

Address all correspondence to: ntulir@unizulu.ac.za

University of Zululand, South Africa

A wide variation in growth and yield of P. vulgaris landraces discussed in this review will enable a possible breeding selection for leaf consumption based on bigger and soft-textured leaves. A selection for green beans can be on pod size, texture, and yield. Further, selection for dry beans can be based on seed yield, size, taste, and cooking time, to name a few. Breeding for resistance toward pests and diseases can be enhanced on landraces with resistant genes.

Morpho-Agronomic Variation among *Phaseolus vulgaris* Landraces: A Review

http://dx.doi.org/10.5772/intechopen.71359

67

[1] Nwadike C, Terkimbi V. Effects of planting date on performance of common bean (Phaseolus vulgaris L) landraces of the Jos plateau: A preliminary studies. International

[2] Adesoye AI, Ojobo OA. Phaseolus spp.: Valuable but underutilized genetic resource in

[3] Kouam EB, Ndomou M, Gouado I, Pasquet RS. Assessment of the genetic diversity of cultivated common beans (Phaseolus vulgaris L.) from Cameroon and Kenya using allozymes

[4] Njoki NB. Breeding for durable resistance to angular leaf spot (Pseudocercospora griseola) in common bean (Phaseolus vulgaris) in Kenya [thesis]. South Africa: University of KwaZulu-

[5] Freitas G, Gananca JFT, Nobrega H, Nunes E, Costa G, Slaski JJ. Morphological evaluation of common bean diversity on the island of Madeira. Genetic Resources and Crop

[6] Piergiovanni AR, Lioi L. Italian common bean landraces: History, genetic diversity, and

[7] Doria E, Campion B, Sparvoli F, Tava A, Nielsen E. Anti-nutrient components and metabolites with health implications in seeds of 10 common bean (Phaseolus vulgaris L. and Phaseolus lunatus L.) landraces cultivated in southern Italy. Journal of Food Compo-

[8] Camara CRS, Carlos A, Urrea CA, Schlegel V. Pinto beans (Phaseolus vulgaris L.) as a

functional food: Implications on human health. Agriculture. 2013;3:90-111

markers. Journal of Experimental Biology and Agricultural Sciences. 2017;5:088-097

Nigeria. International Journal of Plant Breeding and Genetics. 2015;9(1):1-9

Journal of Current Research and Academic Review. 2015;3:309-324

Figure 1. Variation in shape, size, and color of some Italian P. vulgaris landraces [28].
