Crop Protection

Permanent URI for this collectionhttps://etd.hu.edu.et/handle/123456789/50

Browse

Filters

2019 - 201912020 - 20241

Settings

Subject: search.filters.subject.Genotype

Search Results

Now showing 1 - 2 of 2
  • No Thumbnail Available
    Item
    CHICKPEA WILT (FUSARIUM OXYSPORUM F. SP. CICERIS) INTENSITY IN NORTH SHOA, ETHIOPIA, AND EVALUATION OF CHICKPEA GENOTYPES AGAINST THE PATHOGEN
    (Hawassa University College of Agriculture, 2024) Kalkidan Wudu
    Chickpea (Cicer arietinum L) is an important pulse crop in Ethiopia. However, chickpea Fusarium wilt (CFW) is the major constraint on its production. Thus, this study was designed with the following objectives: to assess the prevalence, incidence, and association of biophysical factors with CFW in North Shoa Ethiopia and evaluate chickpea genotypes against the pathogen. For this purpose, a field survey was conducted during the 2022 main growing season. Descriptive statistics and logistic regression model were used to analyze association of the disease with different biophysical factors. Fungal isolation was done out by placing small bits of infected root on PDA at Hawassa University Crop Protection Laboratory. Colony characteristic of the fungus were studied on PDA. The spores were obtained by growing the fungal pure culture on SNA. The pathogen was morphologically identified using appropriate identification manual. Sixteen chickpea genotypes were screened for their reaction to CFW under a lath house condition. The survey results revealed that CFW was prevalent in all the surveyed areas, with different levels of incidence. A higher CFW incidence (43.2%) was recorded at Siyadebrna-wayu district, while a lower (34.8%) CFW incidence was recorded at Ensaro district. High mean CFW incidence was recorded on chickpea sown late August (39.2), desi-type chickpea (39.7), fields previously sown with legumes (43.9),lower altitudes (40.3), pod setting stage (41.2) and weedy fields (45.8%). In the model, crop growth stage, district, previous crop, and weeding practice were significantly associated with FOC incidence. The highest (>38%) wilt incidence was highly associated with weedy fields. The fungal mycelia were white in color. The macro conidia were straight to slightly curve with three septa. While the micro conidia were oval and no septation, Based on these, the pathogen was identified as F. oxysporum f. sp. ciceris (FOC). Three chickpea genotypes (DZ-2012-CK-0312 followed by FLIP12-138c and ICCMABCD-21) were moderately resistant, while nine chickpea genotypes were susceptible. The result of the current study confirmed that CFW was highly prevalent in the study areas. Thus, designing effective CFW management options by targeting important biophysical factors that influence disease pressure and using chickpea varieties that have some degree of resistance to the disease is essential. It would be better to repeat the late house experiment for one or two times and further tests under field conditions to come up with sound recommendations.
  • No Thumbnail Available
    Item
    PHENOTYPIC AND GENOTYPIC CHARACTERIZATION OF THE WHEAT STEM RUST PATHOGEN (Puccinia graminis f.sp. tritici) AND VARIETIES’ REACTION TO MAJOR STEM RUST RACES IN ETHIOPIA
    (Hawassa University College of Agriculture, 2019) TSEGA’AB TESFAYE WANORE
    Stem rust caused by Puccinia graminis f.sp. tritici (Pgt) is one of the most important diseases of wheat (Triticum aestivum) across the globe. Because of the sudden changes in stem rust race patterns, commercial varieties are becoming vulnerable globally at large and particularly in Ethiopia. The objectives of this study were to i) assess the distribution of wheat stem rust across selected major wheat producing regions of Ethiopia, ii) study population diversity of pgt races and iii) identify physiological race and the reaction of wheat genotypes to major races of the pathogen. For this purpose, a total of 464 wheat fields were surveyed in eight zones and 37 wheat producing districts of Amhara and Oromia regional states of Ethiopia. Besides, 60 disease samples were collected for race analyses using 20 differentials in a greenhouse trial and molecular diversity of the pathogen was studied using custom PgtSNP 3.0K chip. The reaction of 75 wheat genotypes and 1 universal susceptible check to major races of the pathogen was also evaluated in the greenhouse. Stem rust prevalence in the surveyed areas ranged from 0 to 100%, while disease incidences and severity varied between 0 and 25% and 0 and 11.5%, respectively. Greenhouse trials involving 20 differential cultivars resulted in the identification of three Pgt races (TKTTF, TTKSK and TTRTF) among the collected stem rust samples. Of these, TTRTF has not been previously reported in Ethiopia and hence, this is the first report of TTRTF in Ethiopia. Race TKTTF, also known as “Digalu race”, was the most frequent (75% frequency) of all the races of Pgt. The remaining two races TTKSK (Ug-99) and TTRTF were detected with frequencies of 4.16 and 22.91%, respectively. Eighty five percent of the stem rust resistance genes (Sr5, Sr21, Sr9e, Sr7b, Sr6 Sr8a, Sr9g, Sr9b, Sr17, Sr9a, Sr9d, Sr10, Sr38 and McN) were ineffective to all the races detected and 30% of the resistance genes were found to be effective to one or more of the races identified. However, in the present study only the differential host carrying Sr24 was effective to all the races identified in the study areas. The presence of the three Pgt races was also confirmed by molecular study, which categorized the isolates into three clades as I, IVB and IIIB for TTKSK, TKTTF and TTRTF, respectively. The resistance screening trial revelaed that five durum wheat genotypes namely Bichena, Tob-6, Assasa, Kokate and DW/NVT-LMA and six bread wheat genotypes namely, Sulla, Hidase, Wane, 36ESWY, ETBW 8459 and 36ESWYT were resistant against all the races at the seedling stage. These resistant genotypes can be used in wheat improvement programs after being checked under field condition for their adult stage resistance.