_____________________________________________________________________________________________________ *Corresponding author: E-mail: eliudgatambia@yahoo.com; Journal of Experimental Agriculture International 14(4): 1-8, 2016, Article no.JEAI.29760 Previously known as American Journal of Experimental Agriculture ISSN: 2231-0606 SCIENCEDOMAIN international www.sciencedomain.org Evaluation of Growth Rate and Phenotypic Traits of Meristem-cultured Papaya Plants E. K. Gatambia 1* , Agnes W. Kihurani 2 , Fredah K. Rimberia 2 and Monica M. Waiganjo 1 1 Kenya Agricultural Research Institute, Thika, Kenya. 2 Department of Horticulture, Jomo Kenyatta University of Agriculture and Technology, Nairobi, Kenya. Authors’ contributions This work was carried out in collaboration between all authors. Authors EKG and FKR designed the study, wrote the protocol and interpreted the data. Authors EKG and AWK anchored the field study, gathered the initial data and performed preliminary data analysis. While authors EKG, FKR and MMW managed the literature searches and produced the initial draft. All authors read and approved the final Manuscript. Article Information DOI: 10.9734/JEAI/2016/29760 Editor(s): (1) Suleyman Korkut, Duzce University, Department of Forest Industrial Engineeering, Division of Wood Mechanic and Technology, Turkey. Reviewers: (1) T. Pullaiah, Sri Krishnadevaaraya University, India. (2) Mahipal S. Shekhawat, MGGAC, India. Complete Peer review History: http://www.sciencedomain.org/review-history/16745 Received 28 th September 2016 Accepted 13 th October 2016 Published 29 th October 2016 ABSTRACT Papaya in vitro-based micropropagation has been attempted for a number of cultivars. This effort has mainly been geared towards production of multiple unisexual planting stocks in large-scale production of papaya. In this study, a comparison was made on growth performance between tissue-culture generated and direct-seeded papaya plants. Key morphological traits ranging from leaf length to days taken to flowering were employed in evaluating the effect of in vitro propagation on papaya compared to conventionally, seeds generated papaya plants. Three papaya lines for each experimental group were selected at 5-leaf stage and transplanted in a greenhouse. These were set in a completely randomized design with three replicates and the plants subjected to the same soil and water treatment. Data on growth characteristics was collected weekly from transplanting to plant flowering. One way ANOVA was used to generate means which were then separated using Student Newman’s Kules test at p≤0.05. The results showed that direct-seeded and the in vitro- generated papaya plants varied slightly in respect to leaf length and width with both falling within Original Research Article