**3.1. Variability of FSP isolates from Aguascalientes, México**

Nineteen isolates of *Fusarium* were obtained from different locations of Aguascalientes, although most of them were collected in Pabellón. Ten isolates were FSP and the other nine were *F. oxysporum* f. sp. *phaseoli* (FOP). As controls, isolates from Guanajuato, México and Veracruz were included. FSP and FOP isolates showed a great variability on morphology (**Figure 1**). Most of the isolates showed radial growth of colony, purple color of colony and variation on mycelial production and conidia size and shapes (**Table 2**). Most of the common bean cultivars were susceptible to most of FSP isolates, mainly those from Mesoamerican genetic race. AFLP molecular markers clearly separated FSP isolates from FOP isolates, but pathogenicity patterns were not associated with *Fusarium* species (**Table 3**) [11].

Significant differences were found in morphology, pathogenicity and AFLP genotype among isolates. Isolates from Veracruz, Guanajuato and Aguascalientes grew faster *in vitro* than those from México and showed the largest conidia. The most pathogenic isolates were from Aguascalientes and Mexico. Bean cultivars with Flor de Mayo (Jalisco race) and Pinto (Durango race) seed coat showed the highest frequencies of resistance to the most of FSP isolates (**Table 2**). Isolates from the State of Mexico were genetically different from the other isolates with genetic dissimilarity of >9% [4].

**3.2. Reactions of common bean germplasm to root rot pathogens under field** 

**Mean 1.50 0.56 2.69**

VER01 Cotaxtla Radial White 1.94 0.72 2.69 + GTO01 Irapuato Radial " 1.27 0.48 2.65 + MEX01 Texcoco Irregular Yellow 1.28 0.47 2.72 +

**Table 2.** Morphological *in vitro* characteristics of *F. solani* f. sp. *phaseoli* isolates from Aguascalientes, México.

**Experiment I.** The greatest root rot severity was found in Flor de Mayo M38, Pinto Zapata, and Azufrado Tapatío, while Pinto Villa, Tlaxcala 62 and Bayo Criollo del Llano showed the low severity. Tlaxcala 62, Bayo Criollo del Llano and Flor de Mayo M38 were more later than Pinto Villa, Azufrado Tapatío and Pinto Zapata. Pinto Villa, Azufrado Tapatío and Pinto Zapata exhibited the best agronomic characteristics (**Table 4**). A negative association between seed yield and root rot severity at vegetative and reproductive stages was found. Seed yield was negatively associated to days to flowering and days to maturity, while phenology was positively related to harvest index. Harvest index was found to be negatively associated to days to flowering and days to maturity. A positive relationship between root rot severity at vegetative and reproduc-

**Germplasm seed coat color/type (genotypes) Genetic race Resistance (%) Susceptibility (%)**

Mesoamérica/Jalisco

Mesoamérica 32 78

7 12

Flor de Mayo (FM Sol, FM Bajío, FM M38) Jalisco 47 53 Pintos (PT Villa, PT Mestizo, PT Zapata) Durango 47 53 Bayos (BY Zacatecas, BY Madero, BY Criollo del Llano) Durango 29 71

Durango (BY Durango, PT Villa, PT UI-114) Durango 13 87 Jalisco (BY Mecentral, AZ Tapatío) Jalisco 10 90

**Table 3.** Resistance/susceptibility percentages in common bean germplasm classified by genetic races in response to

Black/Yellow (NG Altiplano, NG Vizcaya, Tlaxcala 62) Durango/

Mesoamérica (BAT 477, TLP 19, SEQ 12, NG 8025, Río

inoculation with *F. solani* f. sp. *phaseoli* isolates.

**Color of colony Conidia (μm) Aerial** 

Analysis of *Fusarium*-Common Beans Pathosystem in Aguascalientes, Mexico

**mycelium Length Width L/W**

http://dx.doi.org/10.5772/intechopen.72875

107

**conditions**

tive stage was found (**Table 5**).

**48 Mexican FSP isolates**

**10 Aguascalientes FSP isolates**

Tibagí)

**Isolate Origin Growth** 

**pattern**

**Figure 1.** *In vitro* variation of *F. solani* f. sp*. phaseoli* isolates from Aguascalientes, México.



**Table 2.** Morphological *in vitro* characteristics of *F. solani* f. sp. *phaseoli* isolates from Aguascalientes, México.
