Breeding for Resistance to the Sugarbeet Root Maggot¹

Abstract

Thirty-six genetically diverse sugarbeet (Beta vulgaris L.) lines were evaluated to determine their potential resistance to the sugarbeet root maggot, Tetanops myopaeformis Roder. Significant and relatively consistent differences in maggot damage were noted over 3 years. Damage ratings of F, crosses of resistant x susceptible lines tended to be intermediate between those of the parents. Selection for high-and low-maggot damage showed a linear trend in increasing and decreasing maggot damage, respectively. The average decline in the low-damage selection was approximately 5% per cycle. After five cycles of selection, there was no change in the rate of decline, indicating that further selection progress can be made. A greenhouse test confirmed field designations of resistant and susceptible genotypes. A low-damage inbred had lower maggot survival, smaller maggot weight, lower damage ratings, and greater root weight than a susceptible line. (9). Approximately 38% of the U.S. sugarbeet acreage is subject to damage. We estimate the current average annual loss from SBRM to be about 2% of the yield, or 481,000 metric tons.The prime method of controlling this insect has been with chemical pesticides (3). However, these can be expensive, and there is the possibility that the insect could develop resistance to insecticides. Plant resistance to insects has been developed by breeding in many crops and is one of the most efficient and economical methods of control when available.In the United States, several reports indicate that differences exist among sugarbeet genotypes for damage caused by the sugarbeet root aphid, Pemphigus populivenae Fitch (1,4,5,15,16), the green peach aphid, Myzus persicae (Sulzer) (5, 13), the bean aphid, Aphis fabae Scopoli (12, 13), and spider mites Tetranychus spp (13). However, none of these have played an important role in sugarbeet breeding program in the United States. In England, considerable research on plant resistance in sugarbeets has been reported for the green peach aphid (6,7,8,14) and to some extent for the bean aphid (6,8). It is apparent that the potential exists for developing resistance to sugarbeet insect and mite pests.Maxwell and Jennings (11) recently reviewed principles and techniques of insect control and pointed out that incorporation of plant resistance to insects should be an integral part of a breeding program for any crop. Success in identifying sources of resistance is directly related to the diversity of germplasm available and the probability of resistance occurring in these populations. Finding a source of resistance is the first step for further biochemical and genetic studies. Our study was undertaken to determine if resistance of sugarbeets to the SBRM could be found and to determine the degree of resistance and the feasibility of selection for resistance to SBRM in a sugarbeet breeding program. METHODS AND MATERIALSField and laboratory evaluations of sugarbeets and selections for resistance to the sugarbeet root maggot were carried out by personnel of ...

A Sugarbeet Root Maggot (Tetanops myopaeformis Röder) Bioassay Using Beta vulgaris L. Seedlings and In vitro Propagated Transformed Hairy Roots

“…The relative inability to rear SBRM larvae in the laboratory and a need to utilize taproots of greenhouse-or field-grown sugarbeet have collectively hindered the development of an efficient bioassay that would facilitate the screening of new germplasm and other agents for SBRM management (Campbell, 2005;Theurer et al, 1982). In this report, we established a bioassay to study the interactions between sugarbeet roots and SBRM larvae that utilizes sugarbeet seedlings or their corresponding axenic hairy root cultures derived from SBRM-susceptible FIOlO or moderately resistant F1016 germplasm.…”

“…Conventional breeding methods have produced two moderately resistant sugarbeet lines, however, germplasm with a high level of SBRM resistance is still lacking (Campbell et al, 2000;Theurer et al, 1982). Recent advances in molecular biology have the potential to yield a large number of newly developed insect control agents and gerrnplasm that could lead to useful strategies for SBRM management.…”

Screening for Resistance Against the Sugarbeet Root Maggot, Tetanops myopaeformis (Diptera: Ulidiidae), Using a Greenhouse Bioassay

“…Following the first report on genetic factors for resistance to T. myopaeformis feeding in sugar beet ( Theurer et al 1982 ), work on the development of resistant sugar beet varieties has increased. Several varieties have been registered that exhibit lower T. myopaeformis feeding damage relative to susceptible varieties ( Campbell et al 2000 , 2011 ; Campbell 2015 ).…”

Registration of F1024 Sugarbeet Germplasm with Resistance to Sugarbeet Root Maggot

“…Genetic variability for resistance to the root maggot has been recognized since the early 1980s (Theurer et al, 1982; Campbell, 2005), but only two root maggot–resistant germplasm lines, F1015 (PI 605413) and F1016 (PI 608437), have been available to the public (Campbell et al, 2000). In a seedling bioassay (Smigocki et al, 2006), second‐instar root maggot larvae feeding on the roots of susceptible 3‐wk‐old seedlings were more prominent than on resistant seedlings.…”