Inbreeding Coefficient and Mid-parental Value (MP) Can be Used to Estimate Family-mean of Fruit-weight of Offspring in Crossbreeding Test

• Published in: Horticultural Research (Japan) Vol. 16; no. 3; pp. 259 - 264
• Main Authors: Nagasawa, Masashi, Hara, Kazuko, Shibata, Yuki, Ono, Hayato
• Format: Journal Article
• Language: Japanese
• Published: THE JAPANESE SOCIETY FOR HORTICULTURAL SCIENCE 2017
• Subjects: ANOVA; family-mean; inbreeding coefficient; mid-parental value (MP); multiple-regression
• ISSN: 1347-2658; 1880-3571
• DOI: 10.2503/hrj.16.259

Six offspring in each of 26 families and their parents in Japanese pear were evaluated regarding the fruit weight. Analysis of variance of the offspring, which estimated the between- and within-family variance, and multiple-regression of the mean value in a full-sib family with the mid-parental value (MP) and inbreeding coefficient (F) revealed that the genetic differences among families could be explained mostly by MP and F. Genotypic values of offspring in a family were assumed to be normally distributed around the multiple-regression line with the sum of within-family genetic variance and variance due to the deviation of the family-mean from the multiple-regression line. Based on the parental mean performance of 10 fruits on a single tree for five years, the coefficients of multiple-regression of mean values in a full-sib family on MP and F were 0.6263 ± 0.13 and –0.7343 ± 0.20, respectively, and the proportion of offspring with genotypic values and a fruit weight > 350 g was estimated as 23.6 and 1.3% for 0.104 and 0.3438 F values, respectively, in individuals from a cross with MP = 300 g.