Phytophthora root rot caused by Phytophthora capsici (P. capsici) is a serious limitation to pepper production in Southern China, with high temperature and humidity. Mapping PRR resistance genes can provide linked DNA markers for breeding PRR resistant varieties by molecular marker-assisted selection (MAS). Two BC1 populations and an F2 population derived from a cross between P. capsici-resistant accession, Criollo de Morelos 334 (CM334) and P. capsici-susceptible accession, New Mexico Capsicum Accession 10399 (NMCA10399) were used to investigate the genetic characteristics of PRR resistance. PRR resistance to isolate Byl4 (race 3) was controlled by a single dominant gene, PhR10, that was mapped to an interval of 16.39Mb at the end of the long arm of chromosome 10. Integration of bulked segregant analysis (BSA) and Specific Length Amplified Fragment sequencing (SLAF-seq) provided an efficient genetic mapping strategy. Ten polymorphic Simple Sequence Repeat (SSR) markers were found within this region and used to screen the genotypes of 636 BC1 plants, delimiting PhR10 to a 2.57 Mb interval between markers P52-11-21 (1.5 cM away) and P52-11-41 (1.1 cM). A total of 163 genes were annotated within this region and 31 were predicted to be associated with disease resistance. PhR10 is a novel race specific gene for PRR, and this paper describes linked SSR markers suitable for marker-assisted selection of PRR resistant varieties, also laying a foundation for cloning the resistance gene.

A systematic study was conducted on P. pubescens by analyzing thermal characteristics of its rhizome and culm (1.5 m) at different ages, using various analyses such as X-ray diffraction (XRD), differential scanning calorimetry (DSC), and thermogravimetry (TG). For both the rhizome and culm of P. pubescens, the relative crystallinity (Cr) of cellulose increased and then appreciably decreased with increasing age, but the rhizome contained about 10% less Cr than culm. However, the glass transition temperature (Tg) of culm (268.8 to 273.8 °C) was higher than in the rhizome (213.9 to 219.4 °C). The extrapolated initial decomposition temperature (Te) of 1-, 3-, and 5-year-old rhizome were 263.7 °C, 266.1 °C, and 263.9 °C, respectively; the Te of culms of the same age were 289.7 °C, 282.8 °C, and 283.4 °C, respectively. Variance analysis showed no significant differences in the Te of either rhizome or culm of different ages. Taking the chemical characteristics into consideration, it was concluded that the rhizome has a stable composition and good heat resistance.

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