The genetic basis of heterosis of an elite rice hybrid was investigated by using an "immortalized F(2)" population produced by randomly permutated intermating of 240 recombinant inbred lines from a cross between the parents of Shanyou 63, the most widely cultivated hybrid in China. Measurements of heterosis for crosses in the immortalized F(2) population were obtained from replicated field tria...

OR the reasons that heterosis has immense value in practical utilization in F agriculture and the evolutionary significance of heterosis in natural populations is important, a number of investigators have worked on this problem and proposed numerous hypotheses for the explanation of this phenomenon. The hypotheses which have been proposed can be classified into two categories: (a) dominance the...

quantitative valuations of observed heterosis for 11 traits of 15 f1 hybrids generated by half diallel crosses of six diverse rice cultivars (domsefid, hashemi and binam, three iranian local cultivars; dorfak, kadous and ir30, three improved cultivars), were made in this study. fifteen f1 hybrids and their parents were evaluated in a randomized complete block design with three replications at t...

salinity is one of the abiotic stresses and exploitation of heterosis could increase the crop yield and extend the stress tolerance, especially in salinity stress. in this research, a set of full diallel design involving 7×7 crosses from cultivars including flat, bam, ghods, roshan, arg, kavir and pishtaz were conducted in a randomized complete block design with three replications under both no...

HE heterozygous carriers of some genetic variants are superior in fitness to Tthe corresponding homozygotes. The causation of this hybrid vigor or heterosis (euheterosis according to DOBZHANSKY 1952) constitutes an important but as yet little understood problem. One possibility is that some gene alleles are “overdominant” with respect to fitness, and thus give heterosis in heterozygous conditio...

Compared with understanding of biological shape and form, knowledge is sparse regarding what regulates growth and body size of a species. For example, the genetic and physiological causes of heterosis (hybrid vigor) have remained elusive for nearly a century. Here, we investigate gene-expression patterns underlying growth heterosis in the Pacific oyster (Crassostrea gigas) in two partially inbr...

Today the concept of heterotic groups and patterns is fundamental to hybrid breeding theory and practice. Our objectives were to (i) review various hypotheses on the causes of heterosis in maize and on the experimental evidence supporting or refuting them, (ii) examine advantages and disadvantages of the concept of heterotic groups and patterns, (iii) describe the status of heterotic patterns i...

A line (E) of turkeys selected long-term (37 generations) for increased egg production was reciprocally crossed with its randombred control population (RBC1) that served as the base population of the E line to study the influence of long-term selection on the development of nonadditive genetic variation for egg production and body weight traits. Heterosis was significant for BW at 8, 16, and 20...

We hybridized 10 chromosome segment substitution lines (CSSLs) each from two CSSL populations and produced 50 F1 hybrids according to North Carolina Design II. We analyzed the genetic effects and heterosis of yield and yield components in the F1 hybrids and parents in four environments via the additive-dominance genetic model. Yield and yield components of the CSSLs were controlled by combined ...

Heterosis plays a decisive role in maize production worldwide, but its genetic basis remains unclear. In this study, we explored heterosis for ear-weight (EW)-related traits using a North Carolina Experiment III design (Design III) population derived from the elite maize hybrid Zhengdan 958. Quantitative trait loci (QTL) analysis was conducted based on phenotypic data collected from five enviro...