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  • Author or Editor: William K. Harris x
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Despite the popularity of fountain grass (Pennisetum alopecuroides) as a landscape perennial, little research has been conducted on nursery management practices that maximize its overwintering survival and subsequent spring vigor in container production systems. An experiment was conducted to determine the effect of protective covers (a double layer of insulation fabric, a double layer of insulation fabric plus a single sheet of white polyethylene plastic, or no cover), fertilizer application rate (high and low), and substrate moisture content (irrigated when substrate volumetric water content (VWC) fell below 15% and 25%) on the survival rate and vigor of container-grown fountain grass: straight species fountain grass (SFG), ‘Hameln’ fountain grass (HFG), and ‘Little Bunny’ fountain grass (LBFG). Plants were overwintered in a coldframe and were evaluated for survival rate (percent that survived the winter) and vigor (visual rating scale 1 to 5) the following spring. Survival rate and vigor ratings varied among species. However, the highest survival rates (generally 75% or greater) and vigor ratings (generally 3 or greater) were in treatments that used protective covers, though there was not a clear advantage to using white polyethylene in addition to the double layer of insulation fabric. In treatments that used either of the protective covering methods and the high fertilizer application rate, 25% or less of LBFG survived and had vigor ratings of 1.3 or less. In contrast, 75% of LBFG survived when the low fertilizer rate was used in conjunction with either protective covering method. Substrate moisture content only affected the survival rates of SFG and HFG when no protective cover was used, although these survival rates were less than those with covers. These results suggest that protective covers may serve as a tool to minimize winter damage and improve crop quality for the species used in this trial. Because of the varied capacity among these cultivars to tolerate different fertilizer rates and substrate moisture contents, it is recommended that growers use the results of this study as a baseline for conducting site evaluations to determine overwintering techniques that maximize survival and vigor on their facilities.

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Information on genetic relationships and pedigree structure in germplasm collections is vital to breeders in crop improvement programs. In this study, we assessed genetic identity, kinship distance, and parentage–sibship relationships among 37 peach (Prunus persica) accessions and breeding lines using simple sequence repeat (SSR) markers. Pairwise comparisons based on multilocus SSR profiles led to the identification of two synonymous groups including five accessions. Two pairs of parent–offspring and one full sibling relationships were identified using the likelihood method, and Bayesian cluster analysis partitioned the accessions into groups that were partially compatible with the known pedigree, origin, and flesh color. The 37 accessions were grouped into four clusters, which were largely supported by the known pedigree and origin of these accessions. Although the observed mean heterozygosity was 0.219, mean inbreeding coefficient was 0.635, indicating a high degree of inbreeding among the accessions. Eleven of the 15 SSR markers (73.3%) tested were transferable to nine related Prunus species. Results of the study demonstrate that these SSRs could facilitate the assessment of genetic identity and pedigree structure.

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