Morpho-physiological and Yield Responses of Sweet Potato (Ipomoea batatas (L.) Lam.) Genotypes to Frequency of Irrigation under Greenhouse Condition

Abstract

Introduction:The sweet potato (Ipomoea batatas Lam.), is one of the root and tuber crops grown from low land to high land region of Ethiopia. However, its productivity depends on adaptability and tolerance to different environmental stresses and the capacity of the crop to enhance water use efficiency under moisture stress conditions. The objective of this study was to evaluate impact of irrigation interval on morpho-physiological characteristics of sweet potato varieties. Methodology: The trial was a 3 x 2 factorial arrangement in CRD design consisting: three irrigation intervals (daily-control), four days and seven days interval) combined with two sweet potato genotypes (Hawassa-83 and Kulfo) with three replications. Results: The morpho-physiological indicators, morphological traits, water use efficiency (WUE), Relative leaf water content (RLWC), leaf gas exchange, stomata density, and tuber yield were evaluated. The result indicated that morphological traits were significantly (P≤0.05) responded to genotype and irrigation frequencies. As compared to daily irrigation, an extended watering interval Original Research Article2 to seven days irrigation interval significantly reduced leaf number, vine length, branch number and internode length by 55.42, 19.83 cm, 2.17 and 0.35 cm, respectively. Stomata density was strongly responded to genotypes than effect of irrigation frequency. Genotype Hawassa-83 had approximately 2.0 more stomata per mm 2 than genotype Kulfo regardless to irrigation frequency. The interaction effect between genotype and irrigation frequency revealed significant influence on photosynthesis and transpiration rate. The rate of assimilate accumulation was significantly reduced (by 9.97 mol m -2 s -1 ) in Hawassa-83 irrigated due to extended irrigation interval to seven days than variety irrigated daily. Delay irrigation for four and seven days reduced transpiration rate in genotype Hawassa-83 by 0.74 mmol m -2 s -1 and 0.84 mmol m -2 s -1, respectively. Result on WUE indicated that Kulfo was found better in efficiently utilizing water under extended irrigation interval than Hawassa-83. The leaf water content was significantly (P ≤ 0.001) responded to irrigation frequency than genotypes. The higher leaf relative water content was obtained from daily irrigation than extended irrigation interval.

Regulation of root development in nitrogen-susceptible and nitrogen-tolerant sweet potato cultivars under different nitrogen and soil moisture conditions

“…Previous research has demonstrated a close relationship between the movement and distribution of photosynthetic products from leaves to root tubers and various factors, including genotype characteristics, soil N nutrition, and soil moisture [ 7 , 19 ]. High-yielding sweet potato cultivars tend to become hubs for photosynthate supply in their storage roots earlier than low-yielding cultivars [ 15 ].…”

Plasticity in Stoma Morphology of Gemlik Olive (Olea europaea L.) Cultivar under Different Irrigation Intervals

“…Gemlik zeytin çeşidinin yapraklarında saptamış olduğumuz stoma yoğunluğu değerleri, daha önce bu çeşitte incelemeler yapan Öncü [33] ve Al-Naqeeb [34]'in belirtmiş oldukları alt/üst sınır değerleri içerisinde yer almaktadır. Çalışmada elde ettiğimiz; sulama aralığına bağlı olarak yapraklarda stoma yoğunluğunun sınırlı düzeyde değişim gösterebileceği bulgusu Roro ve Tesfaye [36] Farklı bitki türlerinde yürütülen araştırmalarda; genç yaprakların, yaşlı yapraklara göre daha fazla stomaya sahip oldukları bildirmiştir [43][44][45][46][47]. Reich [20], hibrit kavak çeşitlerinde, yaprakların oluştuğu boğum düzeyinin artışına bağlı olarak stoma yoğunluğunun arttığını ancak değişim düzeyinin çeşide özgü olduğunu bildirmiştir.…”