Plateau regression reveals that eight plants per accession are representative for Jatropha germplasm bank

• Published in: Industrial crops and products 2015-03, Vol.65, p.210-215
• Main Authors: Bhering, Leonardo Lopes, Filho, Janeo Eustaquio de Almeida, Peixoto, Leonardo de Azevedo, Laviola, Bruno Galveas, Gomes, Bruno Ermelindo Lopes
• Format: Article
• Language: English
• Subjects: Biofuels; Biometric; Jatropha curcas; Statistics
• ISSN: 0926-6690; 1872-633X
• DOI: 10.1016/j.indcrop.2014.11.056

•Jatropha curcas is one of the most important plants to product biofuels.•Germoplasm bank is important for maintenance of the variabilility of the physic nut.•Jatropha curcas has high potential to increase production for plant with breeding.•To establish the variability, it is necessary for optimal number of plants to represent each genotype. The aim of this study was to estimate the minimum number of perennial Jatropha trees per accession that gives an accurate assessment of available genetic diversity within an accession. Thus, methodologies based on non-linear regression were tested (with linear-plateau response, quadratic-plateau response, and modified maximum curvature) involving ​​grain yield and one hundred seed weight. The germplasm bank used in the experiment had 160 accessions, and 10 plants represented each accession initially. From this, resampling was performed ranging from 2 to 10 plants per line. After resampling, four million analyzes of variance were done for estimating the coefficient of variation, variance within accessions, genetic variance, phenotypic variance, and heritability. Confidence interval was calculated for each parameter. Once it presented acceptable accuracy, heritability was the parameter used for calculating the minimum number of plants between plots, and it was efficient. The modified maximum curvature method estimated less than one plant per accession, which was inefficient in estimating the number of plants to represent the accession. The methods of regression with linear response estimated between 5 and 6 plants, and quadratic-plateau estimated eight plants per accession as minimum number, being R2 superior to 80%. Therefore, eight is the minimum number of plants to represent an accession of Jatropha for maintenance and expansion of germplasm bank.