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Effective Population Size during Grass Germplasm Seed Regeneration
Author(s) -
Johnson R. C.,
Bradley V. L.,
Evans M. A.
Publication year - 2002
Publication title -
crop science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.76
H-Index - 147
eISSN - 1435-0653
pISSN - 0011-183X
DOI - 10.2135/cropsci2002.2860
Subject(s) - biology , lolium perenne , perennial plant , inflorescence , germplasm , population , botany , agronomy , festuca pratensis , poa pratensis , horticulture , poaceae , demography , sociology
Effective population size ( N e ) is the key parameter for predicting genetic drift associated with germplasm regeneration. A major factor reducing N e below the census population size ( N c ) is variation in seed production among plants in a given population. The objectives of this study were to estimate N e / N c associated with variation in seed production in three model wind pollinated, perennial grass species [ Lolium perenne L., Festuca pratensis Huds., and Pseudoroegneria spicata (Pursh) Á. Löve] and to recommend cost effective sampling methodology to maximize N e / N c during seed regeneration. Three accessions of each species were grown at two field locations and variation in seed number among plants and mean seed production per plant used to estimate N e / N c Mean seeds per whole plant, standard deviations, and N e / N c differed among species, and accessions within species ( P < 0.05). For whole plant samples, average N e / N c for each species differed with values of 0.42, 0.51, and 0.63 for L. perenne , F. pratensis , and P. spicata , respectively. However, average N e / N c based on two inflorescences per plant was 0.69, 0.88, and 0.86 for L. perenne , F. pratensis , and P. spicata , respectively, which was higher than that of whole plant samples. This higher N e / N c resulted from the elimination of the variation in inflorescence number per plant, a major source of variation in seed number among plants. The results showed the high potential for genetic drift in small regeneration populations. Increased plant populations and harvesting a constant number of inflorescences per plant are recommended as cost‐effective methods to minimize genetic drift during regeneration of outcrossing grass germplasm.