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United States Department of Agriculture

Agricultural Research Service

Research Project: MANAGEMENT OF TEMPERATE FRUIT NUT AND SPECIALTY CROP GENETIC RESOURCES

Location: National Clonal Germplasm Repository (Corvallis, Oregon)

Title: Improving in vitro mineral nutrition for diverse pear germplasm

Authors
item Reed, Barbara
item Wada, Sugae -
item Denoma, Jeanine
item Niedz, Randall

Submitted to: In Vitro Cellular and Developmental Biology - Plants
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 25, 2013
Publication Date: May 18, 2013
Citation: Reed, B.M., Wada, S., De Noma, J.S., Niedz, R.P. 2013. Improving in vitro mineral nutrition for diverse pear germplasm. In Vitro Cellular and Developmental Biology - Plants. 49(3):343-355. DOI:10.1007/s11627-013-9504-1.

Interpretive Summary: Mineral nutrition of tissue cultured plants is often difficult to optimize due to complex chemical interactions of required nutrients. The USDA-ARS National Clonal Germplasm Repository, Corvallis, Oregon has over 200 shoot cultures of pears, including 18 species and many cultivars. Plant growth response on standard growth medium varies widely due to the wide genetic diversity of this collection. This study was designed as the initial step in determining the optimal mineral nutrient requirements for micropropagation of pear shoot tips. Five mineral nutrient stock solutions from growth medium were chosen for testing: Ammonium nitrate, potassium nitrate, a mix of calcium phosphorous and magnesiom (mesos), micronutrients and iron. Each factor was varied over a range of concentrations. Five pears in three species were grown on each treatment, plant growth responses were measured, and each response analyzed . The factors with the single largest effects on plant response were that increased mesos for improved growth while increased iron decreased growth. Shoot number was affected by ammonium nitrogen and shoot length by mesos . Factors with the largest effects were similar among the genotypes. This approach was very successful for defining the appropriate types and concentrations of mineral nutrients for micropropagation of diverse pears. Initial increases of mesos components greatly improved the quality and growth of a wide range of pear genotypes. Additional tests to determine additional medium modifications are in progress.

Technical Abstract: Mineral nutrition of in vitro plants is often difficult to optimize due to complex chemical interactions of required nutrients. The USDA-ARS National Clonal Germplasm Repository, Corvallis, Oregon has over 200 shoot cultures of pears, including 18 species and many cultivars. Plant growth response on standard growth medium varies widely due to the wide genetic diversity of this collection. This study was designed as the initial step in determining the optimal mineral nutrient requirements for micropropagation of pear shoot tips. Five mineral nutrient factors were defined from MS salts (Murashige and Skoog 1962): NH4NO3, KNO3, mesos (CaCl2'2H20-KH2PO4-MgSO4), micronutrients (B-Cu-Co-I-Mn-Mo-Zn), and Fe-EDTA. Each factor was varied over a range of concentrations. Treatment combinations were selected using response surface methods. Five pears in three species (Pyrus communis ‘Horner 51’, ‘Old Home x Farmingdale 87’ (‘OHxF87’), ‘Winter Nelis’, P. dimorphophylla, and P. ussuriensis ‘Hang Pa Li’), were grown on each treatment combination, responses were measured, and each response analyzed by ANOVA. Analysis identified the factors with the single largest effects on plant response: shoot quality (mesos), leaf spotting/necrosis (mesos), leaf size (mesos), leaf color (mesos, NH4NO3, KNO3) shoot number (NH4NO3, Fe), nodes (NH4NO3, KNO3) and shoot length (mesos, Fe). Factors with the largest effects were similar among the genotypes. This approach was very successful for defining the appropriate types and concentrations of mineral nutrients for micropropagation of diverse pear genotypes. Initial increases of mesos components greatly improved the quality and growth of a wide range of pear genotypes. Additional tests to determine improved medium modifications are in progress.

Last Modified: 4/20/2014
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