Floral Biology and Pollination Efficiency in Yam (Dioscorea spp.)

Paterne A Agre,Malachy O Akoroda,Asrat Asfaw,Robert Asiedu,Alex Edemodu,Jean M Mondo,Patrick Adebola

doi:10.3390/agriculture10110560

Abstract

Yam (Dioscorea spp.) is a monocotyledonous herbaceous vine cultivated for its starchy underground or aerial tubers in the tropics and subtropics. It is an allogamous and polyploid species that reproduces by both sexual and asexual mechanisms. However, many of the landrace cultivars, including most of the popular varieties, reproduce exclusively by vegetative propagation (planting the tubers). These varieties are either sterile or produce sparse and irregular flowering with high flower abortion rate, low fruit and seed set. Production of crossbreed seeds for genetic improvement and for maintaining genetic diversity in yams is, therefore, mainly achieved through natural or managed pollination. Flowering in yam is mostly dioecious and, in some instances, monoecious. Flowering asynchrony, sticky nature of the pollen grains, and cross incompatibility are among the challenges in making genetic progress in yam breeding. There are many limitations in basic and applied knowledge of yam flower biology and pollination. This paper, therefore, reviews the flowering biology, pollination, and methods of improving pollination efficiency in yam breeding programs.

Highlights

Yam is a common name for diverse species in the genus Dioscorea
The yam belt comprises six countries: Nigeria, Ghana, Côte d’Ivoire, Benin, Togo and Cameroon. This zone accounts for ~92% (67.1 million tons) of the annual global yam production [7]
Yam is an important source of dietary nutrients [8,9] with a low glycemic index, which gives better protection against diabetes and obesity [10,11]

Summary

Introduction

Yam is a common name for diverse species in the genus Dioscorea. This genus is composed of~600 species, of which eleven are the main ones cultivated globally and eight of these are grown in Africa [1,2,3,4]. Yam is a common name for diverse species in the genus Dioscorea. ~600 species, of which eleven are the main ones cultivated globally and eight of these are grown in Africa [1,2,3,4]. In Africa, yam is extensively cultivated in a region from West Cameroon to central. The yam belt comprises six countries: Nigeria, Ghana, Côte d’Ivoire, Benin, Togo and Cameroon. This zone accounts for ~92% (67.1 million tons) of the annual global yam production [7]. Yam value chain is a direct income-generating activity for more than five million people in West Africa [12]

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