Browsing by Author "Afutu, Emmanuel"

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    Assessment of Groundnut (Arachis hypogaea L.) Genotypes for Yield and Resistance to Late Leaf Spot and Rosette Diseases
    (Journal of Experimental Agriculture International, 2018) Elsiddig Mohammed, Khalid; Afutu, Emmanuel; Odong, Thomas L.; Okello, David K.; Nuwamanya, Ephraim; Grigon, Olupot; Rubaihayo, Patrick R.; Okori, Patrick
    Groundnut which is a major staple food crop in Uganda is constrained by late leaf spot (LLS) and groundnut rosette disease (GRD), accounting for major economic yield loss. This study was conducted to identify sources of resistance to LLS and GRD and yield potential of selected groundnut genotypes that could be used in breeding programs. Thirty-eight groundnut genotypes were evaluated at the National Semi Arid Resources Research Institute (NaSARRI)-Serere, Eastern Uganda during the first and second seasons of 2015. The experiment was arranged in randomized complete block design with four replications. The results showed highly significant (P < 0.01) genotype-by-season interaction for most of the traits studied. There were significant differences among the genotypes for 100 seed weight (P < 0.01), and dry pod yield and unshelled sample of 100 pods at P < 0.05. Late leaf spot severity (at harvest), GRD incidence (at 12 weeks) and severity (at harvest) were significantly (P < .01) different and positively correlated with Area Under Disease Progress Curve (AUDPC). GRD severity at harvest showed highly significant (P < 0.001) negative correlation with shelling percentage. Both 100 seed weight and unshelled sample of 100 pod showed highly significant (P < 0.01) negative correlations with LLS at harvest, LLS AUDPC, GRD at 12 weeks, GRD AUDPC, and GRD severity. Genotypes susceptible to both LLS and GRD recorded the lowest 100 seed weight. Nine genotypes (Serenut.2, SGV 0001, SGV 0005, SGV 0006, SGV 0019, SGV 0071, SGV 0082, SGV 0083, and SGV 89751T) showed resistance to both diseases with high yield potential. These genotypes could be used to introgress resistance to both diseases in acceptable cultivars which are susceptible.
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    Cowpea Scab Disease (Sphaceloma sp.) in Uganda
    (Crop Protection, 2017-02-27) Afutu, Emmanuel; Agoyi, Eric E.; Amayo, Robert; Biruma, Moses; Rubaihayo, Patrick R.
    Cowpea (Vigna unguiculata L. Walp) is the third most important legume food crop in Uganda. It is the main legume food crop in the Eastern and Northern regions of the country, however, its mean yield is less than 400 kg ha−1. Scab (Sphaceloma sp.) which is a seed-borne disease is one of the major constraints of cowpea production in the country, capable of causing yield losses of up to 100%. Cowpea scab is the anamorph of Elsinoe phaseoli in common bean (bean scab). The disease affects all the above ground parts of the cowpea plant. A study was conducted in the country to determine the incidence, severity and distribution of scab disease in 17 cowpea growing districts across three agro-ecological zones over a two year period. The results indicated that scab disease was widespread in all the districts with mean incidence ranging between 35 and 70% and mean severity 2–4. Tororo and Amuria districts had the highest incidence and severity, while Bukedea and Arua districts recorded the least disease incidence and severity. Cowpea fields located at altitudes above 1200 m.a.s.l had the highest mean disease incidence (82%) and severity (score = 3.4), while fields located on altitudes lying between 771 and 990 m.a.s.l registered the least disease incidence (64.7%) and severity (score = 2.7). The type of cultivar grown and cropping system practiced influenced the incidence and severity of the scab disease. The results of this study also showed that scab had high incidence and severity across districts and altitudes in Uganda suggesting the need to develop resistant cultivars. This indicates the need to establish the variability of the pathogen to inform the breeding programme for development of resistant varieties.