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...

HAT heterosis is a genetic phenomenon cannot be doubted. And yet, in spite of our awareness of this phenomenon for many years, genetic mechanisms responsible for heterosis have not been demonstrated operationally ( SARKISSIAN 1967). That is, it has not been possible to define heterosis-superior growth of a hybrid-in terms of actual operations o r experimental treatments that may have been appli...

The hybrid between Brassica napus and B. rapa displays obvious heterosis in both growth performance and stress tolerances. A comparative transcriptome analysis for B. napus (A(n)A(n)CC genome), B. rapa (A(r)A(r) genome), and its hybrid F1 (A(n)A(r)C genome) was carried out to reveal the possible molecular mechanisms of heterosis at the gene expression level. A total of 40,320 nonredundant unige...

Yield is an important breeding target. As important yield components, boll number per plant (BNP) shows dynamic character and strong heterosis in Upland cotton. However, the genetic basis underlying the dynamic heterosis is poorly understood. In this study, we conducted dynamic quantitative trait loci (QTL) analysis for BNP and heterosis at multiple developmental stages and environments using t...

In spite of commercial use of heterosis in agriculture, the molecular basis of heterosis is poorly understood. It was observed that maize hybrid Zong3/87-1 exhibited an earlier onset or heterosis in radicle emergence. To get insights into the underlying mechanism of heterosis in radicle emergence, differential proteomic analysis between hybrid and its parental lines was performed. In total, the...

Data were 876 birth records and 727 weaning records of straightbred and F3 crossbred calves produced in the third generation of a five-breed diallel. Among straightbreds at birth, Holstein calves were heaviest and widest at the shoulders and hips. Jersey calves were lightest and narrowest at the hips, and Brahman calves were narrowest at the shoulders. Holstein crosses tended to be larger at bi...