Parasitic angiosperm Alectra vogelii Benth is a growing problem in Malawi, particularly with current emphasis on legumes. Therefore, two studies were set in order to understand the possible mechanisms of resistance in cowpea genotypes on their reaction to the parasitic weed. In the first experiment, Mkanakaufiti, IT99K-7-21-2-2XIT82E-16, Sudan 1 and IT82E-16 were grown in Alectra infested and non-infested pots. The experiment (2*4 factorial treatment combination) was arranged in an RCBD and replicated eight times. The second experiment, involved Petri-dish techniques where 4 genotype roots were assessed on their ability to stimulate the germination of A. vogelii as a proxy for germination stimulant production. The experiment was arranged in an RCBD and replicated five times. In the first experiment, data was collected on; the number of days to first Alectra emergence, Alectra shoot counts at 6, 8, 10, and 12 weeks after planting (WAP), Alectra attachment at 5 and 12 WAP, Alectra biomass at 12 WAP, cowpea biomass parameters at 5 and 12 WAP, yield and yield components per pot. While in the second experiment, number of germinated Alectra seeds per Petri dishes was recorded. The results indicated that IT82E-16 (33.25 days) and Sudan 1 (34.25 days) were earlier infested whilst late on IT99K-7-21-2-2XIT82E-16 (38 days) which correlated to the number of Alectra attachments. There were significant differences ( p = 0.05) in weekly Alectra counts between cowpea varieties from 6 up to 10 WAP. Mkanakaufiti and IT99K-7-21-2-2XIT82E-16 were observed with no and few Alectra shoots infestation respectively which was an indicator of resistance mechanism in the study. Number of pods, grain weight (g) and harvest index per pot were significantly affected by inoculation protocol with lower yield on infested cowpea genotypes. The same trend was observed on cowpea varieties where Mkanakaufiti (21.9 g/pot) shown higher yield followed by IT82E-16 (12.5 g/pot) which is susceptible but with tolerance ability to the parasitic weed. The study has shown that resistance mechanisms can be categorized as no or few Alectra shoots, death of Alectra shoots and late infestation. In the Petri dishes, only 3 WAP grown Mkanakaufiti root media failed to induce the germination of Alectra seeds while the opposite occurred on IT82E-16, Sudan 1 and IT99K-7-21-2-2XIT82E-16. On the contrary, 4 WAP grown root media of the four genotypes stimulated Alectra germination which shed more light on the seed behaviour in the soil. This is worth exploring as more could be known to what causes termination of Alectra shoots on Mkanakaufiti. Still, intensifying resistant genotypes should be a goal in order to reduce Alectra seed banks in the soil, thereby, increasing cowpea yield.
The widespread incidence of Alectra vogelii (Benth) on cowpea (Vigna unguiculata (L.) Walp) presents severe challenges on smallholder farmers with a record of yield reduction up to 100% [
Reference [
Alectra vogelii cycle before ground emergence comprised of germination, haustorial induction, attachments to the host roots which allowed penetration of the host vascular cells [
In Malawi, Mkanakaufiti and IT82E-16 cowpea varieties have been released as resistant and tolerant to Alectra vogelii respectively [
Germplasm used in the study have a number of attributes and reactions to abiotic and biotic factors in the environment (
Alectra-host interaction study was conducted in a well-ventilated plastic green house during the hot dry season (from October 2017 for 90 days) at Crop and Soil Sciences Student Research Farm. The site is located at 14˚35'S, 33˚50'E, with the elevation of 1200 metres above sea level, Lilongwe, Malawi. Dried and mature capsule Alectra plant were sampled from groundnut fields in Kalumba located
Cowpea genotypes | Yield potential (kg∙ha−1) | Alectra reaction | Common disease | Crop duration and growth habit | Drought reaction |
---|---|---|---|---|---|
Mkanakaufiti [ | 2500 and released | Resistant | Susceptible to Mosaic Virus | Dwarf and medium | Tolerant |
IT99K-7-21-2-2XIT82E-16 | ** | Resistant | ** | Climber and short | Tolerant |
Sudan 1 [ | 2500 and released | Susceptible | Resistant to Mosaic virus | Dwarf and short | Tolerant |
IT82E-16 [ | 2500 and released | Susceptible with tolerance | Resistant to Mosaic virus | Climber and short | Tolerant |
Note: ** means not available.
at 14˚13.029'S, 033˚48.019'E with an elevation of 1187 metres above sea level during the 2016/17 growing seasons in June. Then after, the inoculum was sun dried for 30 days followed by cleaning.
There were sixty four (64) plastic pots with a uniform diameter of 18 and depth of 17 centimetres. The pots were filled with sandy loamy soil sourced from Bunda forest. Approximately, 0.015 g seeds of Alectra were inoculated on the four pots, after mixing with fine sandy and coarse sandy soil in the ratio of 1:2 respectively [
There were two experimental factors: Cowpea variety; Mkanakaufiti, IT99K-7-21-2-2XIT82E-16, Sudan 1 and IT82E-16. Inoculation protocol; inoculated and non-inoculated. A 2*4 factorial treatment combination was arranged in an Randomised Complete Block Design (RCBD) and replicated eight times. The crops were planted on 10th October, 2017.
Data was collected on the number of days to first Alectra emergence, periodic number of Alectra shoots emerged per pot at 6, 8, 10, and 12 weeks after planting (WAP), Alectra biomass per pot at 12 WAP, number of Alectra attachment at 5 and 12 WAP.
Cowpea growth parameters were the number of days to first cowpea flowering, fresh and dry root, shoot weight (g), shoot to root ratio at 5 WAP and at harvest. Yield parameters included grain yield (g), pod weights (g), number of pods, seed weight (10 or 100 seed size) (g), shelling percent and harvest index. 10 seed size per pot was considered as the maximum number due to low yield on Alectra infested pots. However, a combined 100 seed size was recorded after combination of all replication per variety. Due to the nature of the experiment, soil analyses were not arranged.
A modified root cut assay technique adopted from [
There were twenty plastic pots with a uniform diameter of 22 cm and depth of 20 cm. These were filled with sandy loamy soil sourced from Bunda forest. Four seeds from the four selected cowpea varieties namely; Mkanakaufiti, IT99K-7-21-2-2XIT82E-16 and Sudan I, IT82E-16 were planted per pot and thinned to three, 1 WAP representing an experimental unit. Irrigation was done on daily basis in regard to the water need of each genotype for 3 and 4 WAP. After 3 and 4 WAP, the genotypes were removed gently from the pots with their roots washed free of soils with tap water and rinsed with distilled water.
Alectra seeds were surface disinfected with an aqueous 1% NaOCL (Sodium hypochlorite) solution for about a minute. Then after, ten Petri dishes were lined with two Whatman No. 1 filter papers and moistened with 5 ml of distilled water. Then after, 0.05 g of A. vogelii seeds were placed on the filter papers. The Petri dishes were sealed with parasitic wrappers and covered with aluminum foil to prevent water losses and exclude light respectively. The 10 Petri dishes were incubated for 5 days at 33˚C which coincided with 21 and 28 days growth period of the test plants above.
20 Petri dishes were lined with two layers of Whatman No. 1 filter paper moistened with 5.0 ml of distilled water. Roots from the four cowpea varieties were cut into small pieces and crashed using a knife. 1.0 g of root pieces from each cowpea variety was weighed and placed into the central aluminum foil ring where the precondition, A. vogelii seeds were placed. Then after, 2 to 3 drops of sterile distilled water were added on the roots media in order to facilitate diffusion of the root exudates across the filter paper. Thereafter, the Petri dishes were sealed with plastic wrappers and coated with aluminum foil followed by, incubation at 30˚C for five days.
The experimental factor was cowpea varieties (CV); Mkanakaufiti, IT99K-7-21-2-2XIT82E-16 Sudan I, and IT82E-16. Both grown cowpea genotypes and Petri dishes were arranged in a Randomized complete block design and replicated five times. The crops were planted on 27th December, 2017.
Germination on each Petric dish was checked on the 5th day of incubation. Germinated Alectra vogelii seeds from each Petri dish were counted with the aid of low power (×20) dissecting microscope.
GenStat® 15 edition was used to perform analyses of variance (ANOVA). The difference between means of significant variables was separated using a least significant difference (LSD) at 5% and 10% level. Analysis on number of Alectra shoots, Alectra attachments; cowpea biomass parameters (g), and Alectra biomass (g) were performed after square root transformation of the data [(x + 0.5)0.5] [
Significant difference on the number of days to first Alectra emergence between cowpea varieties at 5 and 12 WAP was observed (
The result has revealed that inoculation protocol x cowpea varieties interaction effect did not significantly affect root biomass (g), shoot biomass (g), shoot to root ratio either fresh or dry at 5 WAP (
Cowpea varieties | NDFAE at 5 WAP | NDFAE at 12 WAP | Number of Alectra attachments at 5 WAP * | Number of Alectra attachments at 12 WAP* |
---|---|---|---|---|
Mkanakaufiti | 40.000b | 84.000c | 0.707a | 0.707a |
IT99K-7-21-2-2XIT82E-16 | 38.000ab | 35.000ab | 3.168ab | 2.29ab |
IT82E-16 | 33.250a | 36.000b | 5.243b | 1.625ab |
Sudan 1 | 34.250ab | 31.750a | 4.722ab | 3.240b |
LSD 5% | 3.891 | 3.268 | 2.965 | 1.932 |
F. prob | 0.011 | <0.001 | 0.029 | 0.080 |
Grand mean | 36.380 | 46.690 | 3.460 | 1.966 |
CV % | 6.700 | 4.400 | 53.600 | 61.500 |
Note: *means analysis was performed after square root transformation of data [(x + 0.5)0.5]. +means the maximum value of 40 and 84 days marks the end of the experiment in phases and indicates that no emergence of A. vogelii occurred.
Factors | Fresh root biomass (g) | Fresh shoot biomass (g) | Shoot to root ratio (fresh) * | Dry root biomass (g) | Dry shoot biomass (g) | Shoot to root ratio (dry)* |
---|---|---|---|---|---|---|
Inoculation protocol | ||||||
Inoculated | 46.100a | 130.400a | 1.937a | 9.510b | 19.600a | 1.794a |
Non-inoculated | 16.800b | 142.900a | 3.114b | 3.700a | 24.300a | 2.883b |
LSD 5% | 10.910 | 17.250 | 0.345 | 2.701 | 5.130 | 0.5231 |
F. prob | <0.001 | 0.147 | <0.001 | <0.001 | 0.070 | <0.001 |
Cowpea varieties | ||||||
Mkanakaufiti | 23.200a | 130.100a | 2.692a | 3.580a | 18.700a | 2.719a |
IT99K-7-21-2-2XIT82E-16 | 29.000ab | 144.300a | 2.605a | 6.310ab | 24.800a | 2.275a |
IT82E-16 | 29.300ab | 134.800a | 2.594a | 6.790ab | 21.900a | 2.431a |
Sudan 1 | 44.100b | 137.300a | 2.210a | 9.730b | 22.400a | 1.930a |
LSD 5% | 15.440 | 24.400 | 0.4881 | 3.820 | 7.260 | 0.7398 |
F. prob | 0.060 | 0.682 | 0.203 | 0.026 | 0.392 | 0.195 |
F. prob for interaction | ||||||
Inoculation protocol * cowpea varieties | 0.289 | 0.387 | 0.938 | 0.258 | 0.181 | 0.944 |
Grand mean | 31.400 | 136.700 | 2.525 | 6.600 | 21.900 | 2.339 |
CV % | 47.300 | 17.200 | 18.600 | 55.600 | 31.800 | 30.400 |
Note: *means analysis was performed after square root transformation of data [(x + 0.5)0.5].
root ratio between the cowpea varieties. Interestingly, low shoot to root ratio was observed on inoculated pots as compared to non-inoculated.
Inoculation protocol by x cowpea varieties interaction was significant on fresh shoot biomass (
Alectra counts at all sampling times was significantly affected by the cowpea varieties. Sudan 1 and IT82E-16 were observed in supporting a higher number of Alectra shoots from 6 WAP (
Inoculation protocol | ||
---|---|---|
Cowpea varieties | Non-inoculated | Inoculated |
IT82E-16 | 7.426 | 4.756 |
IT99K-7-21-2-2XIT82E-16 | 6.658 | 5.772 |
Mkanakaufiti | 11.062 | 8.506 |
Sudan 1 | 6.242 | 9.524 |
LSD 5% | 3.298 |
Factors | Fresh root biomass* (g) | Fresh shoot biomass* (g) | Dry shoot biomass* (g) | Dry root biomass* (g) | Fresh shoot: root ratio* | Dry shoot to root ratio* |
---|---|---|---|---|---|---|
Inoculation protocol | ||||||
Inoculated | 3.692a | 7.847a | 6.221a | 2.354a | 2.431a | 3.441a |
Non-inoculated | 3.096a | 7.139a | 5.606a | 1.925a | 2.444a | 3.487a |
LSD 5% | 0.701 | 1.649 | 1.494 | 0.618 | 0.465 | 1.094 |
F. prob | 0.092 | 0.382 | 0.402 | 0.164 | 0.954 | 0.932 |
Cowpea varieties | ||||||
Mkanakaufiti | 3.506a | 9.784b | 7.433b | 2.106a | 2.992b | 4.033a |
IT99K-7-21-2-2XIT82E-16 | 3.480a | 6.215a | 5.055a | 2.339a | 2.046a | 2.866a |
IT82E-16 | 2.819a | 6.091a | 4.825a | 1.865a | 2.388ab | 3.223a |
Sudan 1 | 3.770a | 7.883ab | 6.340a | 2.250a | 2.326a | 3.736a |
LSD 5% | 0.991 | 2.332 | 2.113 | 0.875 | 0.657 | 1.547 |
F. prob | 0.259 | 0.011 | 0.062 | 0.697 | 0.045 | 0.421 |
F. prob for interaction | ||||||
Inoculation protocol * cowpea varieties | 0.262 | 0.050 | 0.128 | 0.325 | 0.241 | 0.678 |
Grand mean | 3.394 | 7.493 | 5.913 | 2.140 | 2.438 | 3.464 |
CV % | 28.100 | 29.900 | 34.400 | 39.300 | 25.900 | 43.000 |
Note: *means analysis was performed after square root transformation of data [(x + 0.5)0].
Cowpea varieties | AC at 6 WAP* | AC at 7 WAP* | AC at 8 WAP* | AC at 9 WAP* | AC at 10 WAP* | AC at 11 WAP* | AC at 12 WAP* |
---|---|---|---|---|---|---|---|
Mkanakaufiti | 0.707a | 0.707a | 0.707a | 0.707a | 0.707a | 0.707a | 0.707a |
IT99K-7-21-2-2XIT82E-16 | 2.184ab | 3.502b | 4.053ab | 4.280ab | 3.623ab | 2.924a | 2.215a |
IT82E-16 | 2.964ab | 5.839b | 7.887c | 4.966ab | 3.060ab | 3.112a | 2.491a |
Sudan 1 | 4.573b | 5.696b | 6.411bc | 7.944b | 7.345b | 6.568a | 3.375a |
LSD 5% | 2.432 | 2.451 | 3.368 | 4.512 | 4.459 | 5.053 | 3.838 |
F. prob | 0.035 | 0.003 | 0.005 | 0.035 | 0.049 | 0.141 | 0.498 |
Grand mean | 2.607 | 3.936 | 4.765 | 4.474 | 3.684 | 3.328 | 2.197 |
CV % | 58.300 | 38.900 | 44.200 | 63.000 | 75.700 | 94.900 | 109.200 |
Note: *means analysis was performed after square root transformation of data [(x + 0.5)0.5]. WAP means weeks after planting.
observed with no Alectra shoot during the entire growing period. There was an increase in the number of Alectra shoots on the different genotypes used with time. However, from 10 WAP up to 12 WAP Alectra shoot counts were dropping.
There was no significant interaction between inoculation protocol by cowpea varieties on the number of days to first flowering (NDFF), 50% and 100% flowering (
The results revealed that inoculation protocol x cowpea varieties interaction effect did not significantly affect number of pods, pod weight (g), grain weight (g), seed weight (10 seed size) (g), shelling percent and harvest index per pot (
Factors | NDFF | Number of days to 50% flowering | Number of days to 100% flowering |
---|---|---|---|
Inoculation protocol | |||
Inoculated | 49.440a | 56.940a | 63.810a |
Non-inoculated | 51.060a | 56.440a | 63.810a |
LSD 5% | 2.470 | 1.921 | 1.931 |
F. prob | 0.186 | 0.594 | 1.000 |
Cowpea varieties | |||
Mkanakaufiti | 58.380c | 63.120b | 71.000c |
IT99K-7-21-2-2XIT82E-16 | 44.750a | 53.620a | 60.250a |
IT82E-16 | 48.380b | 54.120a | 60.750ab |
Sudan 1 | 49.500b | 55.880a | 63.250b |
LSD 5% | 3.493 | 2.717 | 2.731 |
F. prob | <0.001 | <0.001 | <0.001 |
F. prob for interaction | |||
Inoculation protocol * cowpea varieties | 0.334 | 0.303 | 0.141 |
Grand mean | 50.250 | 56.690 | 63.810 |
CV % | 6.700 | 4.600 | 4.100 |
Note: NDFF means number of days to first flowering.
Factors | Number of pods per pot | Pods weight/pot (g) | Yield/pot (g) | 10 seed size/pot (g) | 100 seed size (g) | Shelling % | Harvest index |
---|---|---|---|---|---|---|---|
Inoculation protocol | |||||||
Inoculated | 9.880a | 16.400a | 11.600a | 1.241a | 12.54 ± 1.405 | 72.400a | 16.13a |
Non-inoculated | 14.000b | 23.800a | 16.500b | 1.130a | 11.78 ± 1.652 | 71.670a | 27.77b |
LSD 5% | 4.08.000 | 7.750 | 4.810 | 0.1194 | ** | 7.473 | 7.823 |
F. prob | 0.048 | 0.061 | 0.048 | 0.066 | ** | 0.841 | 0.006 |
Cowpea varieties | |||||||
Mkanakaufiti | 18.250b | 30.400b | 21.900b | 1.176b | 12.590 ± 0.566 | 72.160a | 20.07ab |
IT99K-7-21-2- 2XIT82E-16 | 8.750a | 14.000a | 10.700a | 1.365c | 13.460 ± 0.622 | 75.490a | 24.92b |
IT82E-16 | 11.250a | 16.600a | 12.500a | 1.354c | 11.430 ± 2.708 | 75.010a | 29.11b |
Sudan 1 | 9.500a | 19.300a | 11.100a | 0.848a | 11.160 ± 0.629 | 65.470a | 13.70a |
LSD 5% | 5.770 | 10.970 | 6.800 | 0.1688 | ** | 10.568 | 11.063 |
F. prob | 0.010 | 0.027 | 0.007 | <.001 | ** | 0.2090 | 0.049 |
F. prob for interaction | |||||||
Inoculation protocol * cowpea varieties | 0.751 | 0.342 | 0.255 | 0.138 | ** | 0.596 | 0.216 |
Grand mean | 11.940 | 20.100 | 14.000 | 1.186 | ** | 72.030 | 21.950 |
CV % | 46.500 | 52.500 | 46.600 | 13.700 | ** | 14.100 | 48.500 |
Note: **means not available.
affected by inoculation protocols. However, pod weight (g), 10 seed size (g) and shelling index was not significant on the inoculation protocol. On the other hand, number of pods, pod weight (g), grain weight (g) and harvest index per pot registered higher output on non-inoculated cowpea genotypes. On variety difference a similar significant trend was observed on number of pods, pod weight (g), yield (g) per pot on their reaction to Alectra infestation or not. Seed weight (g) was significant on between the cowpea varieties with IT99K-7-21-2-2XIT82E-16 and IT82E-16 registering higher seed size whilst Sudan 1 was the least. However, shelling index was not significant on the cowpea varieties. Mkanakaufiti, IT99K-7-21-2-2XIT82E-16 and IT82E-16 were significantly different to Sudan 1 on the harvest index parameter. Even though, harvest index was drastically reduced by Alectra infestation on Sudan 1 as compared to other genotypes used.
No significant difference was observed on both fresh and dry Alectra biomass at 12 WAP between the cowpea varieties. However, no Alectra weight was observed on Mkanakaufiti whilst Sudan 1 registered higher amount (
Alectra shoot counts per Petri dish were significantly different between the cowpea varieties root media prepared at 3 and 4 WAP (
Number of days to first Alectra emergence between the cowpea varieties was significant at 5 and 12 WAP. Earlier infestation of Alectra vogelii on IT82E-16 at 5WAP and Sudan 1 at 12 WAP could be probably due to the level of exudates
Cowpea varieties | Alectra fresh biomass* (g) per pot | Alectra dry biomass* (g) per pot |
---|---|---|
Mkanakaufiti | 0.707a | 0.707a |
IT99K-7-21-2-2XIT82E-16 | 3.133a | 1.986a |
IT82E-16 | 3.646a | 2.675a |
Sudan 1 | 4.909a | 3.692a |
LSD 5% | 5.333 | 3.903 |
F. prob | 0.393 | 0.415 |
Grand mean | 3.099 | 2.265 |
CV % | 107.600 | 107.700 |
Note: *means analysis was performed after square root transformation of data [(x + 0.5)0.5].
Cowpea varieties | Number of germinated Alectra seeds on the 3 WAP root media | Number of germinated Alectra seeds on the 4 WAP root media |
---|---|---|
Mkanakaufiti | 0.707a | 10.610a |
IT99K-7-21-2-2XIT82E-16 | 2.151bc | 11.500ab |
IT82E-16 | 1.651ab | 11.730ab |
Sudan 1 | 3.360c | 13.310b |
LSD 5% | 1.420 | 1.842 |
F-prob. | 0.011 | 0.048 |
Grand mean | 1.970 | 11.790 |
CV % | 52.400 | 11.300 |
Note: *means analysis was performed after square root transformation of data [(x + 0.5)0.5].
produced by the different host crops, suggesting that the cultivars are highly susceptible [
Alectra vogelii counts at all sampling times indicated a significant difference between the cowpea varieties. This indicated the level of susceptibility and host specificity. However, Mkanakaufiti was observed with no Alectra shoots which agrees with its resistance ability in hotspot areas [
Surprisingly, NDFF, number of days to 50% and 100% flowering were not significantly affected by inoculation protocol. On the other hand, it was assumed that infested pots could probably be observed in delayed flowering parameters. The results corresponded to [
Inoculation protocol by x cowpea varieties interaction was not significant on the number of pods, pod weight (g), grain yield (g), 10 seed size (g), shelling percent and harvest index per pot which indicated no correlation on the two factors together. However, number of pods, grain yield (g) and harvest index per pot were significantly affected by inoculation protocol. This indicated that Alectra shoots probably reduced yield as infested pots registered low yield which agreed with 100% reduction of yield in Botswana, observed on the susceptible variety [
Significant interaction between inoculation protocols by x cowpea varieties on fresh shoot biomass was observed at 12 WAP. This could be attributed to the difference in reaction of the four cowpea varieties on the parasitic weed. However, fresh and dry root biomass at 5 WAP was significantly different on the inoculation protocol. This could be due to the presence of Alectra shoots on the susceptible cowpea varieties. This is in agreement as it was assumed that more growth resources were shunted to the root than the shoots [
On the contrary, fresh shoot, dry shoot biomass and fresh shoot to root ratio were significant on cowpea varieties at 12 WAP due to varietal reactions on A. vogelii. In general, cowpea biomass at 12 WAP were low as compared to 5 WAP probably due to aging of the varieties as they had lost most of their leaves. Reference [
In vitro, Alectra induction to germination was significantly affected by variety factor. This could be due to the biochemistry and specificity of the exudates produced by the varieties. Only Mkanakaufiti failed to support Alectra seed germination on root media harvested from 21 days grown cowpea plants. This could be probably due to Mkanakaufiti age where it was observed to be infested in the late stages of the crop under pot study. It is interesting to note that IT82E-16 supported few number compared to IT99K-7-21-2-2XIT82E-16 resistant genotype. This correlated to pot screening results especially on NDFAE at 12 WAP.
Interestingly, Alectra seed germinated on all the four cowpea root media grown for 28 days which agrees with [
In the study, resistance mechanism was observed on Mkanakaufiti with no Alectra shoots during the entire growing period of the crop. However, IT99K-7-21-2-2XIT82E-16 supported few Alectra shoots which dropped in the late stages of growth. Furthermore, death of Alectra shoot on susceptible genotypes and late infestation were the signs of resistance. Yield output was higher on the two cultivars as compared to the two susceptible cultivars but IT82E-16 supported high number of Alectra shoots but produced reasonable yield than Sudan 1. Age of Mkanakaufiti root media affects Alectra seed germination which corresponded to juvenile resistance. However, other genotypes used induced Alectra germination at all times of sampling. This revealed that in the field, the host crops have mechanisms that stop a further growth of the parasitic weed and it’s worth exploring. Still, Mkanakaufiti and IT99K-7-21-2-2XIT82E-16 are suitable varieties for production in Malawi as the inoculum in the soil banks will decrease, thereby, decreasing the level of infestations on other suitable hosts.
The first author would like to acknowledge Lilongwe University of Agriculture and Natural Resources and the McKnight Cowpea Project for financial support to this work. Many thanks to LUANAR Crop and Soil Sciences staff for their excellent administrative and undying support.
Phiri, C.K., Kabambe, V.H., Bokosi, J. and Mumba, P. (2018) Screening for Resistance Mechanisms in Cowpea Genotypes on Alectra vogelii. American Journal of Plant Sciences, 9, 1362-1379. https://doi.org/10.4236/ajps.2018.96099