Leveraging early dry season planting of ginger under irrigation to enhance production from bacterial wilt infected seed rhizome

Abstract

Ginger (Zingiber officinale Rosc.), one of the important export crops grown in Ethiopia for its underground aromatic rhizome, is threatened by the destructive Ginger Bacterial Wilt (GBW) disease. The objective of this study was to evaluate the effect of moisture sources, plant spacing, and nitrogen fertiliser, on rhizome yield and yield attributes of latently infected ginger seed rhizomes. Treatments included two levels of moisture sources (irrigation and rainfall), two levels of plant spacing (40 cm x 15 cm and 40 cm x 30 cm), and three rates of nitrogen fertiliser, i.e., 0, 46 and 92 kg N ha 1 applied in the form of urea. Analysis of variance showed significant (P<0.01) variations between moisture sources and planting space for fresh rhizome yield, but not for N levels. Moisture sources also significantly (P<0.01) affected stand count at harvest, and other yield attributes, viz., number of buds per rhizome per hill, number of rhizomes per plant, rhizome size and rhizome and propagule weight. Planting infected ginger rhizomes early in dry season, with irrigation, led to production of healthy and large rhizomes weighing up to 662 g. Narrow plant spacing showed better yield performance and yield attributes, as opposed to wide spacing; though wide plant spacing was more preferred for management of Ginger Bacterial Wilt during humid and warm weather conditions. This experiment clearly demonstrated that planting ginger rhizomes, which are latently infected with Ralistonia solanacearum early in dry season, using irrigation could be the best option to propagate disease free rhizomes since dry condition successfully restrains bacterial development, disintegrating the pathosystem. i.e., avoiding high humidity, which is one of the ideal conditions for bacterial growth. Early planting in dry season, using irrigation is a cost effective and easily applicable practice to control Ginger Bacterial Wilt disease.