International Journal of Plant Breeding and Genetics

International Journal of Plant Breeding and Genetics ISSN 5756-2148 Vol. 6 (1), pp. 001-008, January, 2019. © International Scholars Journals

Full Length Research Paper

Assessment of phenotypic diversity of macadamia (Macadamia spp) germplasm in Kenya using leaf and fruit morphology

Lucy Gitonga^{1, 2}, Esther Kahangi², Anne Muigai³, Kamau Ngamau², Simon Gichuki⁴, Wilson Cheluget¹ and Simon Wepukhulu¹

¹Kenya Agricultural Research Institute, National Horticultural Research Center, P.O box 01000-220, Thika, Kenya.

²Department of Horticulture, Jomo Kenyatta University of Agriculture and Technology, P.O Box 00200-62000, Nairobi, Kenya.

³Department of Botany, Jomo Kenyatta University of Agriculture and Technology, P.O Box 00200-62000, Nairobi, Kenya.

⁴Kenya Agricultural Research Institute, Biotechnology Center, P.O. Box 00200-57811, Nairobi, Kenya

Accepted 16 September, 2018

Abstract

The ability to identify genetic variation is indispensable to effective management and use of genetic resources. Morphological traits are among the earliest markers used in germplasm characterization and management. Leaf and fruit morphological characteristics were recorded for 23 cultivars of Macadamia using a sample of 30 for each trait and replicated three times. The analysis of variance revealed significant differences in leaf length, width, petiole length and leaf marginal serrations. Significant differences were also revealed in fruit cluster length, number of fruits per cluster, fruit length but not fruit width. Cluster analysis using R statistics grouped the accessions into three major clusters referring to the two cultivated Macadamia species; Macadamia integrifolia and Macadamia tetraphylla displaying the highest dissimilarity, and the hybrids at the intermediate position. These markers are found to be reliable in distinguishing between the macadamia cultivars in Kenya. Among the markers, leaf petiole and marginal serrations are easily assessable and possible to use in distinguishing between the species.

Key words: Genetic diversity, macadamia germplasm, morphological markers, cluster analysis.