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

**Isolate Origin Growth** 

**pattern**

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

106 Fusarium - Plant Diseases, Pathogen Diversity, Genetic Diversity, Resistance and Molecular Markers

AGS01 Sta. Rosa Radial Pink 1.42 0.48 2.97 + AGS02 Pabellón " Purple 1.49 0.55 2.72 — AGS03 El Novillo " " 1.31 0.53 2.48 + AGS04 Pabellón " " 0.73 0.33 2.20 — AGS05 Sta. Rosa " White 1.32 0.40 3.31 + AGS06 Pabellón " " 1.92 0.91 2.11 + AGS07 Pabellón " Purple 1.22 0.34 3.62 + AGS08 Sta.Rosa/Loreto " White 1.38 0.52 2.68 + AGS09 ´´ " Dark purple 1.26 0.37 3.45 — AGS10 Pabellón Irregular Pink 1.19 0.46 2.61 + AGS11 Pabellón Radial Purple 1.43 0.34 4.19 + AGS12 El Molino " Dark purple 2.41 0.64 3.81 — AGS13 Pabellón " Purple 1.33 0.32 4.23 — AGS14 Pabellón " White 1.20 0.45 2.67 + AGS15 Pabellón " Pink 1.33 0.40 3.35 + AGS16 La Luz " White 0.86 0.32 2.60 +

**Mean 1.48 0.46 2.89**

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

**mycelium Length Width L/W**

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


**Table 3.** Resistance/susceptibility percentages in common bean germplasm classified by genetic races in response to inoculation with *F. solani* f. sp. *phaseoli* isolates.


**Experiment II.** No clear relationship between root rot severity and seed yield was found (**Figure 2a**; **Table 5**). Grain yields ranged from 500 to 1250 kg h−1, but we found a clear differentiation among cultivars by reaction to root rots on the basis of seed coat color. Resistance was more frequent in black beans while intermediate reactions were found in Flor de Mayo germplasm and susceptibility was found in pinto beans. No differences on grain yield were detected between resistant and susceptible genotypes in any seed color type. Resistance was common in bred cultivars, as can be seen in pinto or Flor de Mayo bean types (**Table 4**).

**Table 5.** Pearson's correlation coefficients (r) among characteristics of common bean grown in experiments conducted

**Experiment Classification Genotype Days to** 

**Experiment I**

**Experiment II**

**Experiment III**

\*(p≤0.05); \*\*(p≤0.01).

**flowering**

Susceptible FM 2000 47 101 862 9.0

**Table 4.** Phenology, seed yield and root rot severity in common bean germplasm grown in Aguascalientes, México.

**Characteristic Root rot severity (56 d after sowing) Days to flowering**

Seed yield −0.25NS −0.54\*\*

Seed yield −0.11NS 0.29\*\*

Seed yield −0.07NS 0.02NS

Seed yield −0.25\*\* 0.18\*\*

Days to flowering −0.17NS

Days to flowering −0.10NS

Days to flowering −0.09NS

Days to flowering 0.12\*

**Combined irrigated-rainfed experiment**

at Sandovales and Chapingo, México.

RAB 636 43 91 689 2.6 BAT 477 47 95 1052 2.6 **Mean 45 93 846 2.3**

SEA 16 43 91 780 5.3 SEA 15 43 91 688 4.9 **Mean 44 94 777 6.4** Tukey (P = 0.05) 4 5 504 3

III Resistant SEA 20 46 93 798 1.6

**Days to maturity**

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

**Seed yield (kg h−1)**

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

**Root rot severity**

109


**Experiment Classification Genotype Days to** 

Flor de Mayo-Resistant

Flor de Mayo-Susceptible **flowering**

Late FM M38 56 98 547 6.9

Pinto-Susceptible PT Mestizo 38 88 877 5.8

Black-Resistant NG Otomí 43 98 1000 2.3

Black-Susceptible NG Altiplano 51 97 848 3.9

PT Zapata 42 86 703 6.6 AZ Tapatío 43 89 719 6.2 **Mean 43 88 733 5.9**

Tlaxcala 62 56 109 597 5.0 BY Criollo del Llano 56 100 546 5.0 **Mean 56 102 563 5.6** Tukey (P = 0.05) 1 1 218 0.9

PTD-99092 36 88 739 3.5 PTD-99004 46 96 871 3.6 **Mean 44 94 797 3.5**

PTD-99008 43 96 1056 5.8 PT Zapata 36 88 705 5.7 **Mean 41 91 879 5.8**

FMD-99033 40 91 594 3.3

FMD-99019 42 97 747 3.7 FMD-99004 44 88 884 3.7 **Mean 42 92 742 3.6**

FMD-99022 44 92 810 6.0

FMD-99013 40 88 825 5.9 FMD-99002 39 90 768 5.9 **Mean 41 90 801 5.9**

NG 8025 54 96 855 2.4 NGD-99023 50 97 1003 2.6 **Mean 49 97 953 2.4**

NGD-99040 46 100 1055 3.9 NGD-99028 44 99 963 3.8 **Mean 47 99 955 3.9** Tukey (P = 0.05) 3 2 290 1.5

I Early PT Villa 44 89 778 4.9

108 Fusarium - Plant Diseases, Pathogen Diversity, Genetic Diversity, Resistance and Molecular Markers

II Pinto-Resistant PTD-99057 50 97 782 3.5

**Days to maturity** **Seed yield (kg h−1)**

**Root rot severity**

**Table 4.** Phenology, seed yield and root rot severity in common bean germplasm grown in Aguascalientes, México.


**Table 5.** Pearson's correlation coefficients (r) among characteristics of common bean grown in experiments conducted at Sandovales and Chapingo, México.

**Experiment II.** No clear relationship between root rot severity and seed yield was found (**Figure 2a**; **Table 5**). Grain yields ranged from 500 to 1250 kg h−1, but we found a clear differentiation among cultivars by reaction to root rots on the basis of seed coat color. Resistance was more frequent in black beans while intermediate reactions were found in Flor de Mayo germplasm and susceptibility was found in pinto beans. No differences on grain yield were detected between resistant and susceptible genotypes in any seed color type. Resistance was common in bred cultivars, as can be seen in pinto or Flor de Mayo bean types (**Table 4**).

**Figure 2.** Relationship between root rot severity caused by *F. solani* f. sp. *phaseoli* and grain yield in common beans: (a) experiment II and (b) experiment III.

**Experiment III.** As found in E-II, no clear relationship between root rot severity and seed yield was detected in this experiment (**Figure 2b**; **Table 5**). All 36 genotypes showed grain yields ranged from 550 to 1100 kg h−1. Here, we found that most of germplasm showed a root rot severity ranged from 2 to 5.5 (intermediate), while grain yield ranged from 550 to 1000 hg h−1. Only three cultivars were clearly different from all other cultivars: BAT 477 (that showed the highest seed yields), SEA 20 (that exhibited the lowest root rot severity) and Flor de Mayo 2000 (that showed the highest root rot severity). No differences can be appreciated on days to flowering or days to maturity or seed yield between resistant and susceptible cultivars (**Table 4**).

 An opposite pattern was found in grain yield because higher seed yields were found at Chapingo (50–1880 kg h−1 under rainfed conditions and 230–3300 kg h−1 under irrigated conditions) than Sandovales (150–1150 under rainfed and 500–2300 kg h−1 under irrigated conditions) (**Figure 3a** and **b**). No differences on days to flowering are detected between the two groups of genotypes, but resistant germplasm exhibited greater seed yields than susceptible cultivars (**Table 4**).

**Table 6.** Agronomical characteristics on common bean germplasm under rainfed-irrigated conditions in two locations

**Days to flowering Seed yield (kg ha−1) Root rot severity (56 d after sowing)**

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

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

111

Genetic analysis identified one QTL significantly associated with resistance to FSP in BAT 477 growing under controlled conditions. This QTL explained 2.7% of variation in response to the

**3.3. Genetic basis of resistance to root rot pathogens in selected common bean** 

disease and the marker was found at LG 5 [16].

**cultivars**

of México.

**Experiment Sandovales**

**Experiment Chapingo**

**Resistant genotypes**

**Susceptible genotypes**

Rainfed 49 622 5.7 Irrigated 48 1141 4.6

Rainfed 53 940 6.3 Irrigated 54 1730 5.4 Tukey (P = 0.05) 1 109 0.7

G 2494 53 982 4.0 G 4258 44 1015 4.1 97RS101 52 1273 4.3 NG 8025 54 1303 4.6 PT Zapata 44 1303 4.6 **Mean 49 1175 4.3**

G 801 52 947 8.1 SEA 5 51 588 7.7 G 14538 58 653 7.1 G 4523 48 1094 7.0 G 14645 46 763 6.7 **Mean 51 809 7.3** Tukey (P = 0.05) 2 556 2.4

**Rainfed-irrigated experiment.** In Chapingo, germplasm showed later biological cycle and greater seed yields and root rot severity than at Sandovales. In both locations, rainfed conditions reduced seed yields and increased root rot severity (**Table 6**). In this experiment, negative relationship between seed yield and root rot severity was more clear than other experiments and a positive association was found between seed yield and days to flowering and flowering and root rot severity (**Table 5**). The relationship between root rot severity and grain yield exhibited different patterns across locations. In Sandovales, we found a greater variation on root rot severity on the germplasm, while an opposite response was found at Chapingo.


**Table 6.** Agronomical characteristics on common bean germplasm under rainfed-irrigated conditions in two locations of México.

 An opposite pattern was found in grain yield because higher seed yields were found at Chapingo (50–1880 kg h−1 under rainfed conditions and 230–3300 kg h−1 under irrigated conditions) than Sandovales (150–1150 under rainfed and 500–2300 kg h−1 under irrigated conditions) (**Figure 3a** and **b**). No differences on days to flowering are detected between the two groups of genotypes, but resistant germplasm exhibited greater seed yields than susceptible cultivars (**Table 4**).
