Cereals are the most important food source worldwide (FAO, 2014). Wheat is grown mainly to manufacture flour (USDA, 2016). Oat is also cultivated to feed horses or to supply cereals to industries (flakes and flour) and as a green manure or cover in nontillage systems. Sorghum is used for the production of hay and silage and as a crop rotation with winter forages and cereals, as well as soybean (
Plant-parasitic nematodes are difficult to control, but management programs including crop rotation with resistant plants (Stapleton et al., 2010) can reduce their populations (Molinari, 2011). However, resistance to nematodes varies between genotypes (Curto et al., 2012; Karajeh et al 2011; Williamson et al., 2013). In Brazil, the oat genotypes ‘SI 98102b’, ‘SI 98103b’, and ‘SI 98105b’ and 24 others were resistant to
Thus, the objective of this study was to evaluate the resistance of wheat, oat, and sorghum genotypes to
Experiments were conducted in the greenhouse at maximum temperatures of 24.5°C in test 1 and 28°C in test 2 at the Plant Protection Department (UNESP/FCA—Botucatu, São Paulo State, Brazil). The experimental design was completely randomized with five replications. Seven wheat genotypes (‘CD-118’, ‘CD-104’, ‘CD-108’, ‘CD-150’, ‘BRS-220’, ‘BRS-Pardela’, and ‘BRS-Tangará’); five of oat (‘URS-21’, ‘IPR-126’, ‘URS-Gúria’, ‘URS-Tarimba’, and ‘IAC-7’); ten sorghum hybrids (grain sorghum: ‘BRS-332’, ‘BRS-310’, ‘BRS-330’, and ‘BRS-308’; forage sorghum: ‘BRS-610’, ‘BRS-655’, and ‘BRS-700’; and experimental grain sorghum: ‘307.689’, ‘307.671’, and ‘307.343’); and three sorghum–sudangrass hybrids (forage sorghum ‘BRS-802’, ‘BRS-801’, and ‘BRS-800’) were tested. Two tests with the same methodology were conducted to confirm the results.
Wheat, oat, and sorghum were sowed directly in 2,000 cm3 polyethylene pots with a 1,800 cm3 autoclaved substrate (120°C for 2 hr) [soil:sand:organic matter (1:2:1)]. One plant/pot was left after thinning. Nematode eggs were extracted (Hussey and Barker, 1973) and 2 ml with 5,000
The evaluations were conducted 60 d after inoculation. Plant roots were washed in running water, weighed, and stained with Floxine B (Daykin and Hussey, 1985). Gall (GI) and egg-mass (EMI) indexes were obtained according to a 0–5 scale as follows: note 0 (without galls or egg masses); grade 1 (1–2 galls or egg masses per root); grade 2 (3–10 galls or egg masses per root); grade 3 (11–30 galls or egg masses per root); grade 4 (31–100 galls or egg masses per root); and grade 5 (more than 100 galls or egg masses per root) (Taylor and Sasser, 1978).
Roots were processed using a blender centrifugal flotation method (Coolen and D’Herde, 1972) using 0.5% sodium hypochlorite solution. The number of eggs and second-stage juveniles (J2) of the nematodes was evaluated using a Peters slide under light microscopy to obtain the reproduction factor (RF = final population/initial population). Plants with RF equal to or higher than 1.0 were classified as susceptible (S) and lower than 1.0 as resistant (R) to the nematodes (Oostenbrink, 1966).
Data from the sorghum experiment were transformed using the following equation: √x + 0.5 (1) to meet the presuppositions of variance analysis, analyzed with the SISVAR program, and its averages compared using the Tukey test at 5% probability.
Wheat and oat genotypes did not allow
Gall (GI) and egg-mass (EMI) indexes, reproduction factor (RF), and reaction (R) of
Crop | Genotype | Test 1 | Test 2 | ||||||
---|---|---|---|---|---|---|---|---|---|
GI a | EMI a | RF b | R c | GI | EMI | RF | R | ||
|
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Tomato | Rutgers | 4.4 | 3.8 | 12.2 | S | 4.4 | 4.4 | 15.1 | S |
Wheat | CD-150 | 0 | 0 | 0 | R | 1.0 | 0.8 | 0.1 | R |
CD-108 | 0 | 0 | 0 | R | 1.4 | 1.2 | 0.1 | R | |
CD-118 | 0 | 0 | 0 | R | 1.8 | 1.6 | 0.2 | R | |
BRS-220 | 0 | 0 | 0 | R | 2.6 | 2.6 | 0.2 | R | |
BRS-Tangará | 0 | 0 | 0 | R | 2.2 | 2.2 | 0.7 | R | |
CD-104 | 0 | 0 | 0 | R | 0 | 0 | 0 | R | |
BRS-Pardela | 0.4 | 0.2 | 0 | R | 3.0 | 3.0 | 0.3 | R | |
Oat | URS-Gúria | 0 | 0 | 0 | R | 0 | 0 | 0 | R |
URS-Tarimba | 0 | 0 | 0 | R | 0 | 0 | 0 | R | |
URS-21 | 0 | 0 | 0 | R | 0 | 0 | 0 | R | |
IAC-7 | 0 | 0 | 0 | R | 0 | 0 | 0 | R | |
IPR-126 | 0 | 0 | 0 | R | 0 | 0 | 0 | R | |
|
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Tomato | Rutgers | 4.4 | 4.2 | 13.9 | S | 4.2 | 4.0 | 15.4 | S |
Wheat | CD-150 | 0 | 0 | 0 | R | 2.4 | 2.4 | 0.1 | R |
CD-108 | 0 | 0 | 0 | R | 2.4 | 2.2 | 0.1 | R | |
CD-118 | 0 | 0 | 0 | R | 1.8 | 2.2 | 0.3 | R | |
BRS-220 | 0 | 0 | 0 | R | 1.6 | 1.6 | 0.6 | R | |
BRS-Tangará | 0.6 | 0.4 | 0 | R | 1.4 | 0.8 | 0.1 | R | |
CD-104 | 0 | 0 | 0 | R | 3.4 | 0.8 | 0.1 | R | |
BRS-Pardela | 0 | 0 | 0 | R | 2.8 | 3.0 | 0.7 | R | |
Oat | URS-Gúria | 0 | 0 | 0 | R | 0 | 0 | 0 | R |
URS-Tarimba | 0 | 0 | 0 | R | 0 | 0 | 0 | R | |
URS-21 | 0 | 0 | 0 | R | 0 | 0 | 0 | R | |
IAC-7 | 0 | 0 | 0 | R | 0 | 0 | 0 | R | |
IPR-126 | 0 | 0 | 0 | R | 0 | 0 | 0 | R |
GI and EMI = note 0 (without galls or egg masses); grade 1 (1–2 galls or egg masses per root); grade 2 (3–10 galls or egg masses per root); grade 3 (11–30 galls or egg masses per root); grade 4 (31–100 galls or egg masses per root); and grade 5 (more than 100 galls or egg masses per root).
RF = final population (Pf)/initial population (Pi = 5,000).
R = resistant (RF < 1.0); S = susceptible (RF ≥ 1.0).
Sorghum genotypes had different reactions to
Gall (GI) and egg-mass (EMI) indexes, reproduction factor (RF), and reaction (R) of
Genotypes | Type a | Test 1 | Test 2 | ||||||
---|---|---|---|---|---|---|---|---|---|
GI b | EMI b | RF c | R d | GI | EMI | RF | R | ||
|
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Tomato ‘Rutgers’ | - | 4.4 | 4.0 | 15.1 ab | S | 4.6 | 23.26 a | S | |
5.0 | |||||||||
BRS-802 | HF* | 2.8 | 4.6 | 22.6 a | S | 2.4 | 2.9 b | S | |
3.8 | |||||||||
BRS-700 | HF | 3.8 | 3.6 | 13.5 ab | S | 1.4 | 2.8 b | S | |
1.6 | |||||||||
BRS-801 | HF* | 1.8 | 1.0 | 12.2 abc | S | 3.0 | 4.9 b | S | |
4.0 | |||||||||
BRS-308 | HG | 2.8 | 3.4 | 4.6 bcd | S | 4.0 | 4.3 b | S | |
4.0 | |||||||||
307.671 | HEG | 0.6 | 0 | 2.9 cd | S | 0 | 0 c | R | |
0.2 | |||||||||
BRS-655 | HF | 1.2 | 0.8 | 2.3 d | S | 0.2 | 0.4 c | R | |
0.2 | |||||||||
BRS-332 | HG | 1.0 | 0.4 | 2.0 d | S | 0.4 | 0.8 c | R | |
0.6 | |||||||||
307.689 | HEG | 1.4 | 0.6 | 1.3 d | S | 0 | 0 | 0 c | R |
BRS-330 | HG | 0 | 0 | 0.9 d | R | 0 | 0 | 0.3 c | R |
BRS-610 | HF | 0.6 | 0.4 | 0.7 d | R | 0.8 | 0.4 c | R | |
1.2 | |||||||||
BRS-800 | HF* | 1.2 | 0 | 0.5 d | R | 0 | 0 | 0.1 c | R |
BRS-310 | HG | 0.8 | 0.2 | 0.4 d | R | 0 | 0 | 0.1 c | R |
307.343 | HEG | 1.2 | 0.6 | 0.4 d | R | 0 | 0 | 0.1 c | R |
C.V. (%) | - | 44.6 | 20.9 | ||||||
|
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Tomato ‘Rutgers’ | - | 4.2 | 4.0 | 15.3 ab | S | 5.0 | 5.0 | 15.16 a | S |
BRS-802 | HF* | 1.6 | 3.2 | 25.5 a | S | 2.6 | 1.6 | 4.8 cd | S |
BRS-801 | HF* | 2.0 | 2.2 | 15.5 ab | S | 1.2 | 0.8 | 5.0 cd | S |
BRS-700 | HF | 3.2 | 2.8 | 13.9 ab | S | 3.4 | 3.4 | 15.0 b | S |
BRS-655 | HF | 2.0 | 2.0 | 8.0 bc | S | 3.0 | 2.8 | 7.4 c | S |
307.689 | HEG | 1.2 | 0.2 | 1.8 c | S | 0 | 0 | 0 e | R |
BRS-330 | HG | 0.6 | 0 | 1.2 c | S | 0.2 | 0 | 0.7 e | R |
307.671 | HEG | 1.0 | 0 | 1.0 c | S | 0 | 0 | 0 e | R |
BRS-332 | HG | 0.2 | 0 | 0.8 c | R | 0 | 0 | 0.1 e | R |
BRS-800 | HF* | 0 | 0 | 0.9 c | R | 0.2 | 0 | 0.1 e | R |
307.343 | HEG | 1.4 | 0 | 0.5 c | R | 0 | 0 | 0e | R |
BRS-610 | HF | 1.0 | 0 | 0.5 c | R | 1.2 | 0.4 | 0.1 e | R |
BRS-310 | HG | 1.6 | 0.2 | 0.5 c | R | 0.6 | 0.6 | 1.9 de | S |
BRS-308 | HG | 2.2 | 4.0 | 0.3 c | R | 2.2 | 2.0 | 7.8 c | S |
C.V. (%) | - | 38.7 | 26.0 |
Mean values of five replications; mean values followed by the same letter per column did not differ by the Tukey test (
HF* = Foraging hybrid (
GI and EMI = note 0 (without galls or egg masses); grade 1 (1–2 galls or egg masses per root); grade 2 (3–10 galls or egg masses per root); grade 3 (11–30 galls or egg masses per root); grade 4 (31–100 galls or egg masses per root); and grade 5 (more than 100 galls or egg masses per root).
RF = final population (Pf)/initial population (Pi = 5,000).
R = resistant (RF < 1.0); S = susceptible (RF ≥ 1.0).
All the wheat and oat genotypes tested in this study could positively contribute to the management of
Low multiplication of
Oat genotype resistance to
The variability in the resistance of sorghum genotypes to
In summary, all wheat and oat genotypes tested and the sorghum hybrids ‘BRS-610’, ‘BRS-800’, and ‘307.343’ were resistant to