Response of Sorghum landraces to S. hermonthica
Pot-trial
The mean number of emerged Striga plants per pot across all sorghum genotypes was 12.13, while the mean number of Striga plant per sorghum plant was 4.04 (Table 2). This indicates that overall, there is an adequate level of Striga infestation in the study to determine the resistance of sorghum genotypes to Striga.
Table 2
The response of Sorghum landraces to artificially infested S. hermonthica (at 12th WACE) in 2020 to 2021 under pot experimentation at Assosa, Benishangul Gumuz, Ethiopia
Genotypes | Striga count at 12th WACE | Striga per plant | Genotypes | Striga count at 12th WACE | Striga per plant |
Berhan | 0.25n | 0.08n | ETSC19004 | 11.75d − m | 3.92d − m |
ETSL102969 | 0.50n | 0.17n | ETSL102925 | 11.75d − m | 3.92d − m |
ETSL102970 | 1.00mn | 0.33mn | ETSL102944 | 12.00d − l | 4.00d − l |
ETSC20003 | 2.00l − n | 0.67l − n | ETSC20006 | 12.25d − l | 4.08d − l |
ETSL102971 | 2.25k − n | 0.75k − n | ETSL102948 | 12.75d − l | 4.25d − l |
ETSL102975 | 2.25k − n | 0.75k − n | ETSC20001 | 13.00d − k | 4.34d − k |
ETSL102904 | 2.75j − n | 0.92j − n | ETSL102922 | 13.25d − j | 4.42d − j |
ETSC19001 | 3.75i − n | 1.25i − n | Assosa-1 | 14.50d − i | 4.83d − i |
ETSC19003 | 4.25h − n | 1.42h − n | ETSL102942 | 14.75c − h | 4.92c − h |
ETSC20005 | 5.00h − n | 1.67h − n | ETSC19005 | 14.75c − h | 4.92c − h |
ETSL102949 | 5.00h − n | 1.67h − n | ETSL102972 | 16.25c − g | 5.42c − g |
ETSC20002 | 5.25h − n | 1.75h − n | ETSL102946 | 17.00c − g | 5.67c − g |
ETSL102920 | 7.50g − n | 2.50g − n | ETSL102918 | 17.50b − g | 5.83b − g |
ETSL102974 | 8.00g − n | 2.67g − n | ETSL102952 | 18.25b − g | 6.08b − g |
ETSL102941 | 9.50f − n | 3.17f − n | ETSL102955 | 19.25a − f | 6.42a − f |
ETSL102951 | 9.50f − n | 3.17f − n | ETSC20004 | 19.75a − f | 6.58a − f |
ETSC19002 | 10.25e − n | 3.42e − n | ETSL102956 | 20.00a − f | 6.67a − f |
ETSL102912 | 10.25e − n | 3.42e − n | ETSL100053 | 20.50a − e | 6.83a − e |
ETSL102976 | 10.50e − n | 3.50e − n | Adukara | 20.75a − e | 6.92a − e |
ETSL102919 | 10.50e − n | 3.50e − n | ETSL102905 | 21.00a − e | 7.00a − e |
ETSL102896 | 11.00d − n | 3.67d − n | ETSL102947 | 21.50a − d | 7.17a − d |
ETSL102954 | 11.50d − m | 3.84d − m | ETSL102940 | 25.50a − c | 8.50a − c |
ETSL102945 | 11.50d − m | 3.84d − m | ETSL102957 | 28.25ab | 9.42ab |
ETSL102943 | 11.75d − m | 3.92d − m | ETSL102973 | 29.75a | 9.92a |
Mean | 12.13 | 4.04 | | 12.13 | 4.04 |
LSD | 10.765 | 3.59 | | 10.765 | 3.59 |
CV | 23.34 | 16.80 | | 23.34 | 16.80 |
P value | < 0.0001 | < 0.0001 | | < 0.0001 | < 0.0001 |
The results of the pot experiment results indicate that there is a highly significant difference (P < 0.0001) in the response of sorghum landraces to S. hermonthica infestation (Table 2). The average number of emerged Striga plants per pot ranged from 0.25 for the Berhan variety (resistant check) to 29.75 for the ETSL102973 landrace. Similarly, the number of Striga plant per sorghum plant ranged from 0.08 for Berhan to 9.92 for ETSL102973. These findings suggest that ETSL102973 had significantly higher Striga emergence compared to Berhan, indicating its susceptibility to S. hermonthica (Table 2 and Fig. 2). On the other hand, sorghum landraces ETSL102969, and ETSL102970 showed reduced Striga emergence compared to other landraces (Table 2 and Fig. 2).
Sick plot trial
The sick-plot experiment revealed that the mean number of emerged Striga plants per plot was significantly varied (P < 0.05) among sorghum landraces at 12 WACE. Sorghum genotypes exhibited varied Striga emergence per plot that ranged from 3.0 for the Berhan and ETSL102969 to 148.5 for the ETSL102944 sorghum landrace. Likewise, emerged Striga plants per sorghum plant ranged from 0.22 for the ETSL102966 to 5.48 for the ETSL102954 (Table 3 and Fig. 2). The result exposed that the resistant check Berhan and sorghum landrace ETSL102969 sustained the lowest (3.0) Striga emergence (Table 3). Sorghum landraces ETSL102970, ETSL102975, ETSL19001, and ETSL100053 also exhibited lower Striga emergence compared to the resistant check variety Framida in the sick-plot trial (Table 3). The results are consistent with the findings from a previous pot trial (Table 2, and Table 3).
Result of this study revealed that the resistant sorghum genotypes were early maturing with maturity period of 125 days for the Berhan, 142 days for ETSL102970, 144 days for ETSL102969 (Table 3). This argued with the finding of Ayana et al. (2019) that reported early maturing sorghum genotypes showed resistance to S. hermonthica. Franke et al. (2006) was also reported that earlier maturing sorghum genotypes had positive response to Striga stress.
Moreover, S. hermonthica resistant sorghum genotypes of this study were shorter plant heights that ranged from 101.96 cm for ETSL102969 to 139.79 cm for Berhan (Table 3). Similarly, they have lower number of leaves per plant that ranged from 3.45 for ETSL102969 to 5.87 for Berhan (Table 3).
Table 3
The response of sorghum landraces to S. hermonthica under artificially infested sick plot in 2022 at Assosa, Benishangul Gumuz, Ethiopia
Genotypes | Sorghum Parameters | Striga parameters |
Days to flowering | Days to maturity | Sorghum plant height (cm) | Sorghum leafs number | Striga count/plot | Striga plant height | Number of Striga per sorghum |
ETSL102969 | 99.0mn | 144.0klmno | 101.96p | 3.45k | 3.5e | 26.34b | 0.22e |
Berhan | 98.0mno | 125.0op | 139.79nop | 5.87ji | 3.0e | 36.63b | 0.25e |
ETSL102970 | 73.0p | 142.0lmno | 121.91op | 3.95jk | 3.0e | 19.84b | 0.22e |
ETSL102975 | 116.0ijkl | 157.0defghijkl | 207.78ghijklm | 9.65c − h | 7.5de | 30.03b | 0.31de |
ETSC19001 | 134.0d | 161.5cdefghijkl | 151.04jklmno | 5.30jk | 7.5de | 22.08b | 0.30de |
ETSL100053 | 152.0b | 160.0defghijkl | 240.30cdefghi | 10.25abcdefg | 7.5de | 38.33b | 0.28de |
Framida | 117.0hijkl | 135.0mno | 122.89op | 5.89ij | 8.0de | 28.69b | 0.59de |
ETSL102976 | 130.0de | 180.5abc | 234.36defghij | 8.90fgh | 11.5cde | 32.05b | 0.53de |
ETSL102955 | 152.0b | 169.0bcdefg | 258.30abcdefgh | 10.15abcdefg | 14.0bcde | 29.01b | 0.52de |
ETSL102949 | 114.0kl | 154.0efghijklmn | 242.95cdefghi | 7.91hi | 14.5bcde | 30.31b | 0.58de |
ETSL102925 | 119.0fghijkl | 168.0bcdefgh | 265.10abcdefg | 11.22abcd | 15.0bcde | 28.86b | 0.53de |
ETSC20006 | 116.0ijkl | 160.0defghijkl | 209.70fghijklm | 9.11efgh | 17.5bcde | 29.35b | 0.79de |
ETSL102896 | 136.5cd | 159.0defghijkl | 244.97cdefghi | 11.81ab | 18.5bcde | 38.57b | 0.62de |
ETSC19002 | 99.0mn | 152.0fghijklmn | 220.33efghijkl | 11.55abcd | 19.0bcde | 26.01b | 0.79de |
ETSC20002 | 94.0on | 150.0ghijklmn | 154.70mnop | 9.83bcdefgh | 19.5bcde | 93.44a | 0.72de |
ETSL102974 | 193.0a | 148.0hijklmn | 97.60p | 4.28jk | 20.0bcde | 29.77b | 0.78bcd |
ETSL102951 | 124.0efgh | 169.0bcdefg | 171.86klmno | 11.25abcd | 21.5bcde | 33.05b | 0.69de |
ETSC20003 | 91.0o | 146.0jklmn | 161.45mno | 9.60defgh | 22.5bcde | 26.07b | 0.99cde |
ETSC20005 | 123.0efghi | 158.0defghijkl | 201.65hijklm | 10.55abcdefg | 23.0bcde | 22.72b | 0.98bcd |
ETSC19003 | 115.0jkl | 159.0defghijkl | 161.70mno | 8.83gh | 23.5bcde | 39.00b | 1.16cde |
ETSC20004 | 152.0b | 194.5a | 313.00a | 10.78abcdefg | 23.5bcde | 31.14b | 0.86de |
ETSC19004 | 119.0fghijkl | 155.0efghijklm | 198.47ijklm | 10.40abcdefg | 24.0bcde | 30.67b | 1.19cde |
ETSL102904 | 126.0ef | 169.0bcdefg | 267.30abcdef | 9.75bcdefgh | 25.0bcde | 29.84b | 1.25cde |
ETSL102956 | 119.0fghijkl | 186.0ab | 276.84abcde | 9.72bcdefgh | 25.0bcde | 93.35a | 0.99cde |
Assosa-1 | 142.0c | 177.0abcd | 127.85op | 10.71abcdefg | 25.5bcde | 27.88b | 0.97cde |
ETSL102920 | 157.0b | 173.0bcde | 289.61abcd | 10.90abcdefg | 28.0bcde | 26.85b | 0.95cde |
Adukara | 130.0de | 176.0abcd | 163.85lmno | 11.17abcde | 48.5bcde | 33.79b | 1.51cde |
ETSL102940 | 115.0jghijkl | 134.0on | 194.57ijklmn | 10.85abcdefg | 49.5bcde | 26.83b | 2.47abcde |
ETSL102947 | 120.0fghijkl | 105.0p | 303.75ab | 12.08a | 58.0bcde | 29.02b | 4.14abcd |
ETSL102919 | 125.0efg | 169.0bcdefg | 222.09efghijk | 10.59abcdefg | 58.0bcde | 36.19b | 2.73abcde |
ETSL102912 | 122.0fghi | 171.0bcdef | 258.09abcdefgh | 10.68abcdefg | 62.0abcde | 35.24b | 1.94abcde |
ETSL102918 | 152.0b | 165.0cdefghij | 292.84abc | 10.99fabcde | 64.5abcde | 34.89b | 2.27abcde |
ETSL102957 | 154.0b | 167.0bcdefghi | 244.92cdefghi | 10.74abcdefg | 95.5abc | 27.71b | 4.81abc |
ETSL102954 | 137.0cd | 163.0cdefghijk | 241.72cdefghi | 11.09abcde | 104.5ab | 28.08b | 5.48a |
ETSL102944 | 124.0efgh | 196.0a | 249.90bcdefghi | 11.05abcde | 148.5a | 24.13b | 5.11ab |
Mean | 124 | 160.13 | 216.85 | 9.35 | 33.54 | 31.81 | 1.61 |
LSD | 7.83 | 21.75 | 58.13 | 2.1 | 87.66 | 37.9 | 3.89 |
CV | 3.14 | 6.27 | 13.64 | 11.16 | 58.37 | 59.24 | 58.37 |
As illustrated in Fig. 1, the genotypes ETSL102970, Berhan, and ETSL102969 have lower ASNPC values compared to other genotypes, indicating a slower or less severe emergence of Striga plants in these resistant sorghum genotypes. On the other hand, genotypes ETSL102957 and ETSL102944 exhibit higher ASNPC values, suggesting a higher incidence and more rapid emergence of Striga plants in these susceptible sorghum genotypes. The resistant checks (Berhan and Framida) also demonstrate low ASNPC values, indicating their resistance to S. hermonthica infestation. These findings further support the potential resistance of sorghum genotypes ETSL102970, Berhan, and ETSL102969 against S. hermonthica infestation in Assosa, Benishangul Gumuz region of Ethiopia.
Validation trial at hot-spot farmer’s fields
As illustrated in Table 4, the results of the validation trial confirm that the resistant check Berhan and sorghum landrace ETSL102969 have the lowest number of emerged S. hermonthica plants per 4m x4m plot. Additionally, sorghum landrace ETSL102970 has a lower number of emerged S. hermonthica plants compared to the second resistant check Framida. The number of Striga per sorghum plant is also low for Berhan, ETSL102969, and ETSL102970.
On the other hand, susceptible checks ETSL102957 and Assosa-1 variety have the highest count of emerged S. hermonthica plants. These findings indicate that Berhan ETSL102969, and ETSL102970 exhibit promising resistance against S. hermonthica infestation. Overall, this validation trial confirms that these sorghum landraces possess comparable or good resistance to S. hermonthica when compared to resistant checks like Berhan and Framida.
Table 4
Validation of Striga hermonthica resistant sorghum landraces at hot spot farmers’ fields in 2023 at Assosa, Benishangul Gumuz, Ethiopia
Genotypes | Striga plant/plot at 13 WACE | Sorghum plant height (cm) | Days to flowering | Striga per Sorghum | Yield (t ha− 1) |
Berhan | 47.30c | 117.00b | 74.33d | 1.01b | 1.77c |
ETSL102969 | 51.70c | 117.93b | 81.00c | 2.45b | 3.84a |
ETSL102970 | 136.33c | 196.00a | 81.00c | 2.51b | 3.53ab |
Framida | 267.67c | 173.60a | 86.67b | 12.06ab | 3.14abc |
ETSL102975 | 529.70bc | 116.87b | 155.00a | 30.05a | 3.81a |
Assosa-1 | 1156.33ab | 133.27b | 157.00a | 13.72a | 2.29bc |
ETSL102957 | 1638.33a | 140.53b | 155.33a | 17.68a | 2.11bc |
Means | 546.76 | 142.17 | 112.91 | 11.26 | 2.93 |
LSD | 360.24 | 31.48 | 2.15 | 27.54 | 1.67 |
CV | 19.08 | 12.45 | 1.07 | 21.31 | 23.12 |
P value | 0.037 | 0.0006 | < 0.0001 | 0.022 | 0.05 |
The promising sorghum landraces ETSL102969 and ETSL102970 have been found to have higher yielder yield compared to resistant checks in a validation trial. Additionally, the bold seed size and white seed colour of sorghum landrace ETSL102969 are desirable traits by the local farming communities. These traits can be advantageous for the breeding program, as they can be combined with the Striga resistance trait to develop sorghum varieties that have both resistance to Striga infestation and the preferred seed characteristics. By incorporating these additional traits into the breeding program, there is a higher probability of obtaining F-generations that exhibit both white colour and bold sized seeds, along with resistance to S. hermonthica. This would not only benefit the farmers but also contribute towards improving productivity and enhancing market value for sorghum in the region.