Genetic models for quantitatively inherited endosperm characters

Abstract

Genetic models are presented for the analysis of quantitatively inherited characters which are expressed in the triploid endosperm of plants. These models are appropriate for various populations derived from crosses between two homozygous parents where, as a consequence, in the reference population the gene frequencies are half at all segregating loci. The first model, which allows for the estimation of genotypic values, including additive, dominance and first order epistatic effects, can be used with data from the two parental lines, two reciprocal F1 populations, the F2 and the four backcross populations using the F1 as one of the parents. The model was not extended to those four other backcrosses involving the FIR populations as one of the parents. A second model is presented for the estimation of genetic variance components, including the variances of first order epistatic effects. A third model is described for the estimation of genetic variance components in nested designs which arise in pedigree breeding programs using self fertilization. Data from appropriate experiments are used to illustrate the use of the models.

Mapping quantitative trait loci underlying triploid endosperm traits

“…Genetic models for endosperm traits Based on the genetic characteristics of endosperm traits, various genetic models have been proposed to partition the genetic effects of endosperm traits (Gale, 1976;Mo, 1987;Bogyo et al, 1988;Foolad and Jones, 1992;Pooni et al, 1992;Zhu and Weir, 1994;Wu et al, 1998). In order for the paper to be self-contained, these models are summarized and described here.…”

“…First, the endosperm is triploid and has a more complicated genetic constitution than the diploid plant. For a locus with two alleles, Q and q, four genotypes, QQQ, QQq, Qqq and qqq, are possible (Mo, 1987;Bogyo et al, 1988), whereas a diploid plant has only three possible genotypes. Second, the occurrence of the fertilized egg is the beginning of a new generation, so that the embryo and endosperm of a plant represent the next generation.…”

“…Therefore, we need quantitative genetic models to describe the expression of most endosperm traits. Quantitative genetic models have been developed for endosperm traits (Gale, 1976;Mo, 1987;Bogyo et al, 1988;Foolad and Jones, 1992;Pooni et al, 1992;Zhu and Weir, 1994;Wu et al, 1998). However, they are not designed for QTL mapping using molecular markers.…”

Mapping epistatic quantitative trait loci underlying endosperm traits using all markers on the entire genome in a random hybridization design

“…However, classical statistical methodologies (Gale, 1976;Mo, 1987;Bogyo et al, 1988;Foolad and Jones, 1992;Pooni et al, 1992;Zhu and Weir, 1994) generally focus on partitioning the phenotypic variance of an endosperm trait into genetic and nongenetic (environmental) components, and limit the analysis of the genetic variation to the collective properties of genes. With the advent of molecular markers, QTL mapping became popular.…”

Genetical control of amylose content in a diallel set of rice crosses

“…Thus the standard diploid models cannot be applied to study its genetical control. Recently, several models (Gale, 1976;Huidong, 1987;Bogyo et at., 1988;Pooni et at., 1992) have been proposed which are specifically devised to study the inheritance of traits like amylose content. We have applied these models to investigate the genetical control of amylose content among ten sets of basic generations and shown that its expression is not only controlled by nuclear genes but also influenced by cytoplasmic effects and their inter-*Correspondence actions (Pooni et at., 1993).…”