The Genetics of Resistance to Gastrointestinal Parasites in Florida Native Sheep

This 3-page publication provides a brief overview of resistance to gastrointestinal nematode infections in Florida Native sheep. Written by Zaira M. Estrada Reyes, Owen Rae, Carol Postley, and Raluca G. Mateescu, and published by the UF/IFAS Department of Animal Sciences, August 2020.

Genetics of resistance to Fusarium stalk rot caused by Fusarium verticilloides in maize (Zea mays L.)

Fusarium stalk rot disease (FSR), incited by Fusarium verticilloides, is becoming an important biotic production constraint in many major maize growing areas causing substantial yield losses. The present investigation was conducted to understand the genetics of resistance to FSR through six generation means and variances, as a first step in addressing the problem. Five crosses were developed by crossing four FSR susceptible inbreds (VL1043, VL108867, VL121096 and VL1218) with two resistant inbreds (CM202 and CM212). Six generations of the five crosses (VL1043 × CM212, VL108867 × CM202, VL121096 × CM212, VL1218 × CM202 and VL1218 × CM212) were evaluated through artificial disease inoculation during post rainy season of 2018 and summer, 2019. The scaling tests and joint scaling tests indicated the inadequacy of additive-dominance model and showed the presence of epistatic gene effects in all the five crosses for FSR resistance. The study further revealed the importance of additive, dominance and additive × additive gene effects in the expression of FSR. The magnitude and direction of the additive genetic effects [a], dominance genetic effects [d], magnitudes of additive genetic variance (2A) and dominance genetic variance (2D) varied with the genetic background of the crosses over seasons. Duplicate gene interaction was evident in the inheritance of FSR resistance. Both, additive and non-additive components were found important thus reciprocal recurrent selection would be more effective in obtaining FSR resistant maize inbred lines.

The donor properties of resources resistance against the exciter of wheat rust wheat

A collection of soft winter wheat specimens investigated on the artificial infectious background of the leaf rust pathogen and selected resistance among them. The genetics of resistance sign in varieties and specimens were determined by hybridological analysis of F2: Lovrin 32, KM 1485-6-8, VR 89 Bo 22, Beres, Tobarzo, 0-74-8-2, MIKM 1851-80, 4347-4, NS 326-99, 5517 A-5-5 Yr, Florida 302, VR 87 Bo 15, Matyo, NS 1308, 200-830, Polka, NS 2630/1, NS 18-30, HBE 0140-119, HBE 208-120, HBE 0303 156, HBE 0425-156, Tx91v4511, Tx92v4511, Plyska, Zernogradskaya 31, Volshebnitsa, Myronivska 40, Myronivska ostysta, Myronivska 28, Estet, Volynska napivintensivna, Kyivska 8, Expromt, Mironivska 29, Remeslivna, Garant, Selyanka, Erythrospermum 15761, Erythrospermum 12557, Erythrospermum 12735, Vympel odeskyiy during 1990–2018. The gene non-identity of the investigated donors was determined. In a variety of VR 89 Bo 22, 2 resistance genes, one of them Lr19, was investigated. The results of investigations of the composition of the leaf rust pathogen population by a series of isogenic lines and varieties of carriers of known effective resistance genes are presented. The high resistance against the leaf rust pathogen in the forest-steppe of Ukraine provide the genes Lr9, Lr19, Lr37, Lr42 + Lr24, Lr43 (Lr21 + Lr39) + Lr24, Lr9 + Lr26, Lr10 + Lr24.

Trichothecenes in Cereal Grains – An Update

Trichothecenes are sesquiterpenoid mycotoxins produced by fungi from the order Hypocreales, including members of the Fusarium genus that infect cereal grain crops. Different trichothecene-producing Fusarium species and strains have different trichothecene chemotypes belonging to the Type A and B class. These fungi cause a disease of small grain cereals, called Fusarium head blight, and their toxins contaminate host tissues. As potent inhibitors of eukaryotic protein synthesis, trichothecenes pose a health risk to human and animal consumers of infected cereal grains. In 2009, Foroud and Eudes published a review of trichothecenes in cereal grains for human consumption. As an update to this review, the work herein provides a comprehensive and multi-disciplinary review of the Fusarium trichothecenes covering topics in chemistry and biochemistry, pathogen biology, trichothecene toxicity, molecular mechanisms of resistance or detoxification, genetics of resistance and breeding strategies to reduce their contamination of wheat and barley.