Characterization of Greenbug (Homoptera: Aphididae) Resistance in Synthetic Hexaploid Wheats

Abstract

Twelve greenbug (Schizaphis graminum (Rondani)) biotype E-resistant synthetic hexaploid wheats synthesized by crossing Triticum dicoccum Schrank. and Aegilops tauschii (Coss.) Schmal. were evaluated for the three known insect resistance categories, including antibiosis, anti-xenosis, and tolerance. Different methods were evaluated for calculating antibiosis and tolerance. Calculating intrinsic rate of population increase and measuring leaf chlorophyll content with a SPAD chlorophyll meter proved to be time- and labor-efficient for antibiosis and tolerance determination, respectively. The resistance in all synthetic hexaploids proved to be the result of a combination of antibiosis, antixenosis, and tolerance, which makes them valuable sources of greenbug resistance. To assist plant breeders in selecting the best germplasm for greenbug resistance, a plant resistance index was created that revealed differences among the synthetic hexaploid wheats.

Effect of Different Constant Temperatures on Biology of Schizaphis Graminum (Rondani) (Hemiptera: Aphididae) on Barley, Hordeum Vulgare L. (Poaceae) in Iran

“…In all tested temperatures estimated intrinsic rate of increase and net reproductive rate was greater than for the same species reared on synthetic hexapolid wheat and several varieties of S. paspalum (0.01-0.198) (12.3-40.4) respectively (Lage et al 2003;Nuessly et al 2008). The calculated λ values were almost similar to those estimated for A. gossypii at 10 to 30°C (1.06-1.52).…”

“…The greenbug, Schizaphis graminum Rondani, is a cosmopolitan aphid distributed nearly worldwide (Lage et al 2003). They are dominant cereal aphids that can infest winter and spring sown barley crops in Iran (Rezvani 2001).…”

Mapping resistance to the bird cherry-oat aphid and the greenbug in wheat using sequence-based genotyping

“…We attribute that the 2DL region was not previously reported in A. tauschii (1027) because it was associated to aphids/tiller in the field, whereas Zhu et al (2005) evaluated symptoms based on chlorosis (tolerance) in a greenhouse test similar to ours, where we also did not find any association to 2DL. It is possible that QGb8 has a predominantly antixenotic effect on S. graminum since Lage et al (Lage et al 2003) showed that A. tauschii accession#1027 was the most antixenotic among 12 studied SHWs. However, reduced aphids/tiller could also be due to antibiosis since CWI76364 showed to be more antixenotic, antibiotic and tolerant than the susceptible cultivar Seri M82 (Lage et al 2003).…”

“…It is possible that QGb8 has a predominantly antixenotic effect on S. graminum since Lage et al (Lage et al 2003) showed that A. tauschii accession#1027 was the most antixenotic among 12 studied SHWs. However, reduced aphids/tiller could also be due to antibiosis since CWI76364 showed to be more antixenotic, antibiotic and tolerant than the susceptible cultivar Seri M82 (Lage et al 2003). Further investigation is required to confirm and characterize QGb8 and determine the type of resistance it confers against S. graminum.…”

“…The pedigree of CWI76364 is: Triticum dicoccum PI 94623/A. tauschii (1027) (Lage et al 2003). This A. tauschii accession was also progenitor of the population where the Gba resistance gene was mapped by Zhu et al (2005).…”