University of Khartoum

Effect of Water Potentials on Growth, Yield and Water-use Efficiency of Cowpea (Vigna unguiculata [L] Walp)

Effect of Water Potentials on Growth, Yield and Water-use Efficiency of Cowpea (Vigna unguiculata [L] Walp)

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Title: Effect of Water Potentials on Growth, Yield and Water-use Efficiency of Cowpea (Vigna unguiculata [L] Walp)
Author: Suliman, Abdelshakoor Haroun
Abstract: A field experiment was conducted for two consecutive seasons during 2003/2004 and 2004/2005 in the Demonstration Farm of the Faculty of Agriculture, University of Khartoum at Shambat to study the effect of different water stress levels on growth, yield and water-use efficiency of cowpea (Vigna unguiculata L. [Walp]) cultivars. Two cowpea cultivars were used in this study, namely: Ein el Ghazal (Line 1-12-3) and Dahab el Goz (IT84s-2163). Six water stress levels (-2.5, -5.0, -7.5, -10.0, -12.5, and -15.0 bars) as estimated by predawn leaf water potential using pressure chamber was applied. Characters studied include: growth attributes (number of leaves per plant, leaf area index, leaf area ratio, shoot\\\\\\\\root ratio, specific leaf weight, number of nodules per plant, root length and dry matter production), phonological characters (days to first floral bud appearance, days to 50% flowering, days to maturity), yield and yield components (number of pods per plant, number of harvested pods per plant, percent pod shedding, number of seeds per pod, 1000- seed weight, seed yield, and harvest index). Crop water-use and water-use efficiency were also calculated. The results showed that water stress treatments significantly reduced the number of leaves per plant, leaf area index, leaf area ratio, shoot\\\\\\\\root ratio and biomass production. Water stress also shortened the number of days to first floral bud appearance, flowering and maturity. Similarly, seed yield was significantly reduced by water stress treatments, particularly at lower soil water potentials (-12.5 and -15.0 bar). The reduction in yield was associated with substantial reductions in yield components. In addition, water use and water use efficiency were significantly affected by water stress treatments. Significant differences were observed between the two cultivars in the different characters studied. In this respect, Dahab el Goz (V2) exhibits vigorous growth (greater number of leaves per plant, leaf area index, leaf area ratio and deep root system) and seed yield compared to Ein el Ghazal (V1). Phonologically, V2 was also significantly earlier than V1 under all watering stress levels. The differences in crop water-use and water-use efficiency between the cultivars may be related to the differences in their performance observed in this study. The critical water stress levels as estimated by soil water potentials for cowpea growth and yield were found to be lower than -10.0 bars. The morphological and physiological bases of drought adaptation (i.e. deep rooting, delayed leaf senescence and early maturation) in cowpea were discussed.
URI: http://khartoumspace.uofk.edu/handle/123456789/13015
Date: 2015-06-16


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