Breeding for Resistance to Alfalfa Root Rot Caused by Fusarium Species

Abstract

Fusarium root and crown rot is a significant factor in stand and yield reduction of alfalfa (Medicago sativa L.). The objectives of this study were to develop a greenhouse inoculation procedure for screening alfalfa germplasm for resistance to root rot caused by Fusarium species, collect virulent isolates of Fusarium species from New York, and determine progress from two cycles of recurrent phenotypic selection. Fusarium avenaceum (Fr.: Fr.) Sacc., F. oxysporum Schlechtend.:Fr., and F. solani (Mart.) Sacc. were isolated from rotted alfalfa roots and crowns in each of four regions of New York. At least one of the three species was present in every field sampled, but not all species were found in every field. The V‐V8 inoculation method was developed by culturing the Fusarium species in vermiculite saturated with V8 juice; the inoculum was placed in contact with severed alfalfa root balls in pots. This method was as effective as the application technique for inciting infection of alfalfa roots; however, the Y‐Y8 method was more efficient for mass inoculation of plants. Using the V‐V8 method in the greenhouse, we subjected two alfalfa populations to two cycles of recurrent phenotypic selection for resistance to root rot caused by each of the three Fusarium species. Mean lesion length (vertical discoloration) within taproots was the selection criterion. Only selection for resistance to disease caused by F. solani was effective; mean lesion length decreased by 34% from Cycle 0 to Cycle 2 in Oneida, and by 48% in (Flamande × SaranacAR‐2)AN. Future selection should account for lateral spread as well as vertical length of lesions.

Modulation of protein expression in alfalfa (Medicago sativa L.) root and leaf tissues by Fusarium proliferatum

“…Fusarium spp.-induced root rot is a recurrent disease causing significant yield losses of many food crops including alfalfa (Miller-Garvin and Viands 1994;Salter et al 1994;Leath and Kendall 1977;Cong et al 2016), field pea (Pisum sativum) (Chittem et al 2015), soybean and chickpea (Cicer arietinum) (Cabral et al 2016). Although both monogenic and quantitative resistance have been studied in different legumes (Schneider et al 2001;Ramírez-Suero et al 2009;Vitale et al 2014;Cabral et al 2016), only monogenic resistances has been used in current breeding programs for legume crops and single gene resistance is less durable and constantly tested under the pressure of emerging Fusarium spp.…”

“…Fungal infection is one of the major threats to alfalfa production (Cramer et al 2011). For example, alfalfa root rot disease caused by Fusarium species (e.g., F. proliferatum and F. solani) often cause significant reduction of alfalfa stand density and biomass loss worldwide (Leath and Kendall 1977;Salter et al 1994;Cong et al 2016). Currently, the most common and effective control method to combat this pathogen is to grow disease resistant cultivars.…”

Relationships among alfalfa resistance to Sclerotinia crown and stem rot, Sclerotinia trifoliorum and oxalic acid

“…The relative low number of plants resistant to at least one disease makes breeders to compose initial breeding populations using several thousands of plants. Development of population using such number of selected resistance plants allows testing young plants for resistance to other disease under greenhouse conditions, for example, Fusarium crown rot (Salter et al, 1994). This layout of screenings makes possibility for selecting plants resistant to couple of diseases.…”

Resistance of lucerne (<i>Medicago</i> spp.) germinating seeds to oxalic acid

“…The relatively low number of plants resistant to at least one disease makes breeders use several thousands of plants in order to compose the initial breeding populations. Development of a population using such a number of plants selected for resistance allows testing young plants for resistance to other diseases under greenhouse conditions, for example, Fusarium crown rot [25,26]. This layout of screenings allows for selecting plants resistant to a couple of diseases.…”