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ARS Home » Pacific West Area » Corvallis, Oregon » National Clonal Germplasm Repository » Research » Publications at this Location » Publication #311307

Research Project: Management of Temperate-Adapted Fruit, Nut, and Specialty Crop Genetic Resources and Associated Information

Location: National Clonal Germplasm Repository

Title: Determining optimum in vitro mineral nutrition for diverse pear germplasm using response surface methodology

Author
item REED, BARBARA
item DE NOMA, JEANINE
item WADA, SUGAE - OREGON STATE UNIVERSITY
item Niedz, Randall

Submitted to: Acta Horticulturae
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/21/2015
Publication Date: 3/1/2016
Citation: Reed, B.M., De Noma, J.S., Wada, S., Niedz, R.P. 2016. Determining optimum in vitro mineral nutrition for diverse pear germplasm using response surface methodology. Acta Horticulturae. 1113:79-84.

Interpretive Summary: It is very difficult to optimize mineral nutrition of tissue culture plants because the minerals in the growth medium interact with each other to affect plant growth. The USDA-ARS National Clonal Germplasm Repository, Corvallis, Oregon has about 1700 unique pears in the field and over 200 as tissue cultures, including 18 species and many cultivars. Plant growth response on standard tissue culture medium varies widely due to the wide horticultural diversity of this collection. A group of studies were designed to determine the mineral nutrient requirements for micropropagation of pear shoots from this diverse collection. Initially, five mineral nutrient factors were tested and each factor was varied over a range of concentrations. Five pear genotypes in three species were grown on each treatment combination. Measurements included several important growth responses such as shoot quality, severity of leaf spotting/necrosis, leaf size, shoot number, and shoot length, and each response was analyzed. The mineral factors with the largest growth responses were identified. Additional experiments determined the optimal concentrations of these factors for each individual pear type. Mineral nutrient formulations were identified for each pear that resulted in significantly better growth. This approach was very successful for defining new media for shoot culture of diverse pear germplasm.

Technical Abstract: Complex chemical interactions in media and variation in genotype response make it very difficult to optimize mineral nutrition of in vitro plants. The USDA-ARS National Clonal Germplasm Repository, Corvallis, Oregon has about 2000 unique pear (Pyrus L.) accessions in the field and over 200 as in vitro cultures, including 18 species and many cultivars. Plant growth response on standard tissue culture medium varies widely due to the wide diversity of this collection. A group of studies were designed to determine the mineral nutrient requirements for micropropagation of pear shoots from this diverse collection. Initially, five mineral nutrient factors were created from MS salts – NH4NO3, KNO3, mesos (Ca-Mg-Cl-Mn-SO4-PO4), metals (Zn-Mn-Cu-Co-Mo-B-I), and Fe-EDTA. Each factor was varied over a range of concentrations. Treatment combinations were selected using response surface methodology (RSM). Five pear genotypes in three species (Pyrus communis, P. dimorphophylla and P. ussuriensis) were grown on each treatment combination. Measurements included shoot quality, severity of leaf spotting/necrosis, leaf size, shoot number, and shoot length, and each response was analyzed by ANOVA with results modeled using RSM. Models for each genotype identified the factors with the largest growth responses. Additional experiments testing mesos and nitrogen compounds determined the optimal concentrations of these factors for a wider range of pear species and cultivars. Mineral nutrient formulations were identified that resulted in significantly better growth for all the genotypes tested. This approach was very successful for defining new media for shoot proliferation of diverse pear germplasm.