Browsing by Author "Emongor, V.E."

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    Effect of levels and timing of application of gibberellic acid on growth and yield components of common beans
    (African Crop Science Society, 2003-09-15) Ngatia, T.M.; Shibairo, Solomon I.; Emongor, V.E.; Obukosia, S.D.
    This study was conducted to determine the effect of levels and timing of application of gibberellic acid (GA3) on growth and yield components of common beans (Phaseolus vulgaris L.). Experiments were conducted at the Field Station Farm at the Faculty of Agriculture, University of Nairobi, Kenya during 1997 and 1998. "Mwezi moja" bean cultivar was used in study. Gibberellic acid (GA3) was sprayed at 0, 2.5, 5.0 and 7.5 mg l-1 to whole bean plants at 7, 14 or 28 days after emergence (DAE). The effect of GA3 and timing of application on growth, yield and yield components was significant (P<0.05). Applications of GA3 led to increased plant height, leaf area index (LAI), fractional solar radiation interception, root, shoot and the total dry mass. It also increased yield per plant, pods per plant, 100-seed mass and harvest index. The highest seed yields were equivallent to 1854 kg ha-1 in 1997 and 5890 kg ha-1 in 1998. These yields are high as compared to average national yields of 500 kg ha-1. Significant differences in the parameters measured were generally observed at 14 DAE in GA3 treated plants.
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    Effects of ethephon on the growth, yield and yield components of beans (Phaseolus vulgaris L.)
    (JKUAT, 2003) Ngatia, M.; Shibairo, Solomon I.; Emongor, V.E.; Kimenju, J.W.
    Two experiments to determine the effects of timing and levels of application of ethephon on the growth and yield of common bean (Phaseolus vulgaris L). were conducted. Bean cultivar \'Mwezi moja\' was used. Four levels of ethephon (0, 100, 200 and 300 mg/l) were sprayed to the plants at 7, 14 or at 28 days after emergence (DAE). Application of ethephon at all the three timings led to reduced plant height. Application of ethephon at 28 DAE reduced the leaf area index (LAI), fractional solar radiation interception, shoot dry mass and total dry mass. Root dry mass was not affected by ethephon application. Application of ethephon particularly at 28 DAE reduced yield and number of pods per plant. Application at 7 and 14 DAE in experiment 1 and 28 DAE in both experiments increased the number of seeds per pod. Ethephon application at 14 DAE increased the 100-seed mass in experiment 1 but reduced it in experiment 2. Most reduction in 100-seed mass occurred with application at 28 DAE. The harvest indices were reduced by application of ethephon at 28 DAE in both experiments and 14 DAE in experiment 1. It was concluded that ethephon (ethylene) application did not have any beneficial effects in bean production.