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Pragmatic Methods for Perennial Ryegrass (Lolium perenne L.) Breeding
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| 자료유형 | 학위논문 |
|---|---|
| 서명/저자사항 | Pragmatic Methods for Perennial Ryegrass (Lolium perenne L.) Breeding. |
| 개인저자 | Heineck, Garett C. |
| 단체저자명 | University of Minnesota. Applied Plant Sciences. |
| 발행사항 | [S.l.]: University of Minnesota., 2019. |
| 발행사항 | Ann Arbor: ProQuest Dissertations & Theses, 2019. |
| 형태사항 | 194 p. |
| 기본자료 저록 | Dissertations Abstracts International 81-04B. Dissertation Abstract International |
| ISBN | 9781392640418 |
| 학위논문주기 | Thesis (Ph.D.)--University of Minnesota, 2019. |
| 일반주기 |
Source: Dissertations Abstracts International, Volume: 81-04, Section: B.
Advisor: Watkins, Eric |
| 이용제한사항 | This item must not be sold to any third party vendors. |
| 요약 | This dissertation consists of five chapters, each was written as a stand-alone manuscript. The introduction of each chapter serves, in part, as the introductory literature review. Herein is described a brief summary of each chapter's introduction, methods, and results. Chapter 1Crown and stem rust are major diseases of perennial ryegrass (Lolium perenne L.). Plant breeders and pathologists often rate rust severity in the field using the modified Cobb scale, but this method is subjective and labor intensive. A novel, open-source system using ImageJ and R was developed to quantify pustule number and area using digital images collected from spaced plants in the field. The computer-processing pipeline included development of training data for prediction of pixel identity using random forest and noise reduction spatial processing. Raters and the computer scored rust severity on plant images of varying complexity including whole-plant (WP), five-leaf (FL), and single-leaf (SL) image series. Computer accuracy was determined using the SL, while the FL series gave insight into the true value of WP severity. Rater ability was assessed using a panel of nine scientists with varying levels of disease rating experience. Results showed rater perceptions of crown rust severity were very consistent across images, but agreement on severity values for a given image were low. Rater consistency for stem rust severity was low and FL scores were not strongly correlated with WP scores (r=0.36, P=0.03) indicating low rater accuracy. The computer-processing pipeline was able to accurately discriminate, count and quantify crown and stem rust pustules on leaf samples. Correlations between computer and the median rater score for crown rust were excellent (r>0.90, P< 0.001) for all image series. Similar to raters, there was lack of correlation between WP and FL series (r=0.20, NS) indicating this technique is limited to leaf or stem samples for stem rust and not applicable to WP. However, the computer-processing pipeline shows promise in replacing visual rating of WP for crown rust.Chapter 2Perennial ryegrass is an important turf and forage species that often becomes infected with crown rust caused by Puccinia coronata f. sp. lolii. Disease control through Clavicipitaceous endophytes has been proposed as a potential biocontrol. Two field experiments were designed to determine the influence of native Epichloe endophyte infection on natural rust infection across a diverse panel of perennial ryegrass germplasm. Experiment 1 used an isogenic population design in which clonal plants infected (E+) or endophyte free (E-) were nested within 14 perennial ryegrass entries. Experiment 2 consisted of E+ and E- progeny from isogenic parents. Results showed the endophyte had no consistent marginal effect on crown rust severity across or within entries |
| 요약 | Overall, increased competition between spaced plants increased the predicative ability (rs) for both turfgrass and seed production traits. Furthermore, the competitive design takes up less space and often makes measurements and observations much easier for bunch-type grasses. |
| 일반주제명 | Horticulture. |
| 언어 | 영어 |
| 바로가기 | 
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