Genotypic Variation in Responses of Citrus spp. to Arbuscular Mycorrhizal Fungi

Abstract

Thailand is part of Southeast Asia that covers the center of diversity of citrus species, where various species of the genus are widely grown. One of the most common is tangerine (Citrus reticulata), which is commonly grown by grafting on rootstocks of different tangerine varieties or other citrus species. The objective of this study is to investigate responses of some Citrus spp. seedlings to arbuscular mycorrhizal (AM) fungi, and thus their potential as rootstocks. The experiment was done with four tangerine varieties, Cleopatra, Fremont, Ocean and Sainamphung; and four other citrus species, lime (C. aurantifolia), pomelo (C. maxima), sweet orange (C. sinensis) and Troyer citrange (Citrus sinensis Poncirus trifoliata), in pots for five months. Roots of non-inoculated plants were not infected with AM fungi, while inoculated plants were heavily infected with AM fungi, and contained 14-28 AM spores per 10 g of rhizosphere soil. Most of the citrus responded positively to AM fungi, but with different magnitudes among the varieties and species. Lime and pomelo seedlings were fast growing compared to other citrus species. Total dry weight and N, P, K and Mg contents were increased most strongly by AM fungi in lime, pomelo and tangerine varieties Ocean, Fremont and Sainamphung, but little or none in Cleopatra, Troyer and sweet orange. Lime was the most outstanding in the response to AM fungi, followed by Ocean tangerine and pomelo. The potential of lime, pomelo and Ocean tangerine as rootstock for tangerine should be further investigated.

Mycorrhizal Symbiosis Enhances P Uptake and Indole-3-Acetic Acid Accumulation to Improve Root Morphology in Different Citrus Genotypes

“…Furthermore, the data presented indicate that AMF inoculation, particularly with F. mosseae, greatly increases plant growth, with the degree of growth being genotype-dependent. This is consistent with Youpensuk et al [27], who found varying growth responses in various citrus genotypes after mixed AMF inoculation. Li et al [26] also reinforced this by demonstrating genotype-specific growth enhancement effects in citrus.…”

Patterns of endorhizal fungal associations in fruit crops of southern India

“…In this study, most of the fruit crops except Coccinia grandis, Durio zibethinus, Arto-carpus heterophyllus, and Litchi chinensis were mycorrhizal. A high incidence of mycorrhizae in horticultural fruit crops may be due to their high mycorrhizal dependency as shown by several inoculation experiments (Aseri et al, 2008;Bukhari and Rodrigues, 2008;Youpensuk et al, 2009). The level of AM colonization depends on the physiological status of the host as well as the host genotype (Smith and Read, 2008).…”