Lygus pratensis (L.) is an important cotton pest in China, especially in the northwest region. Nymphs and adults cause serious quality and yield losses. However, the genetic structure and geographic distribution of L. pratensis is not well known. We analyzed genetic diversity, geographical structure, gene flow, and population dynamics of L. pratensis in northwest China using mitochondrial and n...

Members of genus Neotyphodium are asexual derivatives of sexual Epichloë species and maintain endophytic relationships with many cool-season grasses. Most Neotyphodium species analyzed so far are interspecific hybrids with combined or partial genomes of two or three ancestral species. In this study we characterized Neotyphodium isolates from Cinna arundinacea, a perennial cool-season grass from...

The genetic control of apomixis was studied in numerous segregating progenies originated from intercrossing and selfing of obligate sexual and facultative apomictic parents in Poa pratensis by means of the flow cytometric seed screen. The data support a novel model with five major genes required to control asexual seed formation: the Apospory initiator (Ait) gene, the Apospory preventer (Apv) g...

A single chromosome of the grass species Festuca pratensis has been introgressed into Lolium perenne to produce a diploid monosomic substitution line 2n = 2x = 14. In this line recombination occurs throughout the length of the F. pratensis/L. perenne bivalent. The F. pratensis chromosome and recombinants between it and its L. perenne homeologue can be visualized using genomic in situ hybridizat...

Ungrazed tallgrass prairie plots in the Kansas Flint Hills have been burned annually at 4 different dates since 1928. Time of burning markedly altered the physiognomy and was the crucial factor effecting vegetation change. Late-spring burning, coinciding with emergence of the warm-season perennial grasses, increased grass production and favored Andropogon gerardii and Sorghastrum nutans. Burnin...

For some years the Seed-Testing Laboratories of the Bureau of Plant Industry has been using daily alternating temperatures for the germination of certain seeds. In these alternations the lower temperature is used about 18 hours and the higher temperature about 6 hours of the day. Alternating temperatures are found especially favorable for the germination of the seeds of certain grasses: Johnson...